Improvement of in vitro corrosion and cytocompatibility of biodegradable Fe surface modified by Zn ion implantation

Energy Technology Data Exchange (ETDEWEB)

Wang, Henan; Zheng, Yang; Li, Yan, E-mail: liyan@buaa.edu.cn; Jiang, Chengbao

2017-05-01

Highlights: • Fe{sub 2}O{sub 3}/ZnO oxides were formed on the surface of Zn implanted pure Fe samples. • The corrosion rate of the pure Fe in SBF was increased after Zn implantation. • Cytocompatibility of the pure Fe was improved by Zn ion implantation. - Abstract: Pure Fe was surface-modified by Zn ion implantation to improve the biodegradable behavior and cytocompatibility. Surface topography, chemical composition, corrosion resistance and cytocompatibility were investigated. Atomic force microscopy, auger electron spectroscopy and X-ray photoelectron spectroscopy results showed that Zn was implanted into the surface of pure Fe in the depth of 40–60 nm and Fe{sub 2}O{sub 3}/ZnO oxides were formed on the outmost surface. Electrochemical measurements and immersion tests revealed an improved degradable behavior for the Zn-implanted Fe samples. An approximately 12% reduction in the corrosion potential (E{sub corr}) and a 10-fold increase in the corrosion current density (i{sub corr}) were obtained after Zn ion implantation with a moderate incident ion dose, which was attributed to the enhanced pitting corrosion. The surface free energy of pure Fe was decreased by Zn ion implantation. The results of direct cell culture indicated that the short-term (4 h) cytocompatibility of MC3T3-E1 cells was promoted by the implanted Zn on the surface.

Improvement of in vitro corrosion and cytocompatibility of biodegradable Fe surface modified by Zn ion implantation

Science.gov (United States)

Wang, Henan; Zheng, Yang; Li, Yan; Jiang, Chengbao

2017-05-01

Pure Fe was surface-modified by Zn ion implantation to improve the biodegradable behavior and cytocompatibility. Surface topography, chemical composition, corrosion resistance and cytocompatibility were investigated. Atomic force microscopy, auger electron spectroscopy and X-ray photoelectron spectroscopy results showed that Zn was implanted into the surface of pure Fe in the depth of 40-60 nm and Fe2O3/ZnO oxides were formed on the outmost surface. Electrochemical measurements and immersion tests revealed an improved degradable behavior for the Zn-implanted Fe samples. An approximately 12% reduction in the corrosion potential (Ecorr) and a 10-fold increase in the corrosion current density (icorr) were obtained after Zn ion implantation with a moderate incident ion dose, which was attributed to the enhanced pitting corrosion. The surface free energy of pure Fe was decreased by Zn ion implantation. The results of direct cell culture indicated that the short-term (4 h) cytocompatibility of MC3T3-E1 cells was promoted by the implanted Zn on the surface.

Regenerated collagen fibers with grooved surface texture: Physicochemical characterization and cytocompatibility

International Nuclear Information System (INIS)

Wang, Xiang; Wu, Tong; Wang, Wei; Huang, Chen; Jin, Xiangyu

2016-01-01

A novel type of protein fibers, regenerated collagen fibers (RC) from cattle skin, was prepared through wet-spinning. Due to the combined effect of solvent exchange and subsequent drawing process, the fibers were found to have a grooved surface texture. The grooves provided not only ordered topographical cues, but also increased surface area. Protein content of the RC fibers was confirmed by Fourier Transform infrared spectroscopy (FTIR) and ninhydrin color reaction. The fibers could be readily fabricated into nonwovens or other textiles, owning to their comparable physical properties to other commercialized fibers. Cell growth behavior on RC nonwovens suggested both early adhesion and prompt proliferation. The high moisture regain, good processability, along with the excellent cytocompatibility indicated that the RC fibers and nonwovens developed in this study might offer a good candidate for biomedical and healthcare applications. - Highlights: • Wet-spun regenerated collagen fibers having aligned surface grooves • Comparable physiochemical properties to commercialized fibers • Readily processed into nonwovens • Excellent cytocompatibility with prompt cell adhesion and proliferation

Regenerated collagen fibers with grooved surface texture: Physicochemical characterization and cytocompatibility

Energy Technology Data Exchange (ETDEWEB)

Wang, Xiang [Engineering Research Center of Technical Textiles, Ministry of Education, College of Textiles, Donghua University, Shanghai 201620 (China); Wu, Tong [College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620 (China); Wang, Wei [Engineering Research Center of Technical Textiles, Ministry of Education, College of Textiles, Donghua University, Shanghai 201620 (China); Huang, Chen, E-mail: hc@dhu.edu.cn [Engineering Research Center of Technical Textiles, Ministry of Education, College of Textiles, Donghua University, Shanghai 201620 (China); Jin, Xiangyu [Engineering Research Center of Technical Textiles, Ministry of Education, College of Textiles, Donghua University, Shanghai 201620 (China)

2016-01-01

A novel type of protein fibers, regenerated collagen fibers (RC) from cattle skin, was prepared through wet-spinning. Due to the combined effect of solvent exchange and subsequent drawing process, the fibers were found to have a grooved surface texture. The grooves provided not only ordered topographical cues, but also increased surface area. Protein content of the RC fibers was confirmed by Fourier Transform infrared spectroscopy (FTIR) and ninhydrin color reaction. The fibers could be readily fabricated into nonwovens or other textiles, owning to their comparable physical properties to other commercialized fibers. Cell growth behavior on RC nonwovens suggested both early adhesion and prompt proliferation. The high moisture regain, good processability, along with the excellent cytocompatibility indicated that the RC fibers and nonwovens developed in this study might offer a good candidate for biomedical and healthcare applications. - Highlights: • Wet-spun regenerated collagen fibers having aligned surface grooves • Comparable physiochemical properties to commercialized fibers • Readily processed into nonwovens • Excellent cytocompatibility with prompt cell adhesion and proliferation.

Cytocompatibility of amine functionalized carbon nanoparticles grafted on polyethylene

Energy Technology Data Exchange (ETDEWEB)

Žáková, Pavlína, E-mail: pavlina.zakova@vscht.cz [Department of Solid State Engineering, University of Chemistry and Technology, 166 28 Prague 6 (Czech Republic); Slepičková Kasálková, Nikola [Department of Solid State Engineering, University of Chemistry and Technology, 166 28 Prague 6 (Czech Republic); Kolská, Zdeňka [Faculty of Science, J. E. Purkyně University, Ústí nad Labem (Czech Republic); Leitner, Jindřich [Department of Solid State Engineering, University of Chemistry and Technology, 166 28 Prague 6 (Czech Republic); Karpíšková, Jana; Stibor, Ivan [Institute for Nanomaterials, Advanced Technologies and Innovation, Technical University of Liberec (Czech Republic); Slepička, Petr; Švorčík, Václav [Department of Solid State Engineering, University of Chemistry and Technology, 166 28 Prague 6 (Czech Republic)

2016-03-01

Five types of amide–amine Carbon Nano-Particles (CNPs) were prepared by functionalization of CNPs and characterized by several analytical methods. The successful grafting of amines on CNPs was verified by X-ray photoelectron spectroscopy (XPS), organic elemental analysis and electrokinetic analysis. The size and morphology of CNPs were determined from transmission electron microscopy. The surface area and porosity of CNPs were examined by adsorption and desorption isotherms. Differential scanning calorimetry was used to investigate thermal stability of CNPs. The amount of bonded amine depends on its dimensionality arrangement. Surface area and pore volumes of CNPs decrease several times after individual amino-compound grafting. Selected types of functionalized CNPs were grafted onto a plasma activated surface of HDPE. The successful grafting of CNPs on the polymer surface was verified by XPS. Wettability was determined by contact angle measurements. Surface morphology and roughness were studied by atomic force microscopy. A dramatic decrease of contact angle and surface morphology was observed on CNP grafted polymer surface. Cytocompatibility of modified surfaces was studied in vitro, by determination of adhesion, proliferation and viability of vascular smooth muscle cells (VSMCs). Grafting of CNPs onto the polymer surface has a positive effect on the adhesion, proliferation and viability of VSMCs. - Highlights: • Amine functionalized CNPs were successfully grafted on HDPE surface. • Significant change to the positive zeta potential for grafted CNPs was induced. • Grafting of CNPs significantly enhanced cell cytocompatibility and viability. • Homogeneous distribution of cells with correct size was achieved.

Enhanced cytocompatibility of silver-containing biointerface by constructing nitrogen functionalities

Energy Technology Data Exchange (ETDEWEB)

Zhang, Wei, E-mail: weizhang@mail.ipc.ac.cn [Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Liu, Jun [Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Wang, Huaiyu [Department of Physics & Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China); Xu, Ying; Wang, Pingli [Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Ji, Junhui, E-mail: jhji@mail.ipc.ac.cn [Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Chu, Paul K. [Department of Physics & Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China)

2015-09-15

Graphical abstract: Constructing nitrogen functionalities is promising method to enhance cytocompatibility of the biointerface by simultaneous Ag and N{sub 2} plasma modification. - Highlights: • N{sub 2} plasma immersion ion implantation (PIII) treatment generates plenty of nitrogen functionalities on polymer substrate. • N{sub 2} PIII treatment increases surface roughness and hydrophilicity and improves its capability to adsorb protein. • Simultaneous Ag and N{sub 2} plasma modification constructs nitrogen functionalities to enhance cytocompatibility of the biointerface. - Abstract: Silver (Ag) has recently been introduced into polymeric biomedical implants by plasma immersion ion implantation (PIII) to enhance the antibacterial capability. However, Ag ions and nanoparticles can increase the cytotoxicity and inhibit cellular proliferation and the relationship is time- and dose-dependent. In this study, Ag and N{sub 2} PIII is conducted in concert to produce nitrogen functional groups as well as Ag-containing biointerface. In addition to the creation of nitrogen functionalities, the surface roughness and hydrophilicity are improved in favor of protein adsorption. Compared to the biointerface created by Ag PIII only, the nitrogen functionalities generated by N{sub 2} co-PIII do not affect DNA synthesis and the total protein level but evidently enhance cellular adhesion, viability, and proliferation at the biointerface. The modified surface is observed to upregulate the osteogenesis-related marker expression of bone cells in contact. Our findings suggest that dual Ag and N{sub 2} PIII is a desirable technique to enhance both the cytocompatibility and antibacterial capability of medical polymers.

Optimized in vitro procedure for assessing the cytocompatibility of magnesium-based biomaterials.

Science.gov (United States)

Jung, Ole; Smeets, Ralf; Porchetta, Dario; Kopp, Alexander; Ptock, Christoph; Müller, Ute; Heiland, Max; Schwade, Max; Behr, Björn; Kröger, Nadja; Kluwe, Lan; Hanken, Henning; Hartjen, Philip

2015-09-01

Magnesium (Mg) is a promising biomaterial for degradable implant applications that has been extensively studied in vitro and in vivo in recent years. In this study, we developed a procedure that allows an optimized and uniform in vitro assessment of the cytocompatibility of Mg-based materials while respecting the standard protocol DIN EN ISO 10993-5:2009. The mouse fibroblast line L-929 was chosen as the preferred assay cell line and MEM supplemented with 10% FCS, penicillin/streptomycin and 4mM l-glutamine as the favored assay medium. The procedure consists of (1) an indirect assessment of effects of soluble Mg corrosion products in material extracts and (2) a direct assessment of the surface compatibility in terms of cell attachment and cytotoxicity originating from active corrosion processes. The indirect assessment allows the quantification of cell-proliferation (BrdU-assay), viability (XTT-assay) as well as cytotoxicity (LDH-assay) of the mouse fibroblasts incubated with material extracts. Direct assessment visualizes cells attached to the test materials by means of live-dead staining. The colorimetric assays and the visual evaluation complement each other and the combination of both provides an optimized and simple procedure for assessing the cytocompatibility of Mg-based biomaterials in vitro. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Improvement of cytocompatibility of polylactide by filling with marine algae powder

Energy Technology Data Exchange (ETDEWEB)

Wu, Tung-Yi [Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan (China); Yang, Ming-Chien, E-mail: myang@mail.ntust.edu.tw [Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan (China); Hsu, Yi-Chiang [Graduate Institute of Medical Science, College of Health Sciences, Chang Jung Christian University, Tainan 71101, Taiwan (China); Innovative Research Center of Medicine, College of Health Sciences, Chang Jung Christian University, Tainan 71101, Taiwan (China)

2015-05-01

This work evaluated the cytocompatibility, thermal and mechanical properties of composites of polylactide (PLA) and marine algae powder (MAP). To improve the thermal and mechanical properties of PLA–MAP composites, glycidyl methacrylate (GMA) was used as the compatibilizer for the blending of PLA and MAP. The PLA-g-GMA/MAP composites exhibited superior mechanical properties, attributing to higher compatibility between the polymer and MAP, comparing to PLA/MAP composites. The dispersion of MAP in the PLA-g-GMA matrix was highly homogeneous as a result of etherification. The lower melt torque of the PLA-g-GMA/MAP composites also made them more processable than PLA/MAP. To assess the cytocompatibility, normal human foreskin fibroblasts (FBs) were seeded onto each type of the composites. Results of FB proliferation, collagen production, and cytotoxicity assays indicated greater cytocompatibility for the PLA/MAP composites than for the PLA-g-GMA/MAP composites. Furthermore, both PLA/MAP and PLA-g-GMA/MAP composites were more cytocompatible than pure PLA. - Highlights: • PLA was grafted with GMA to form ether bond with marine algae powder (MAP). • Composites of PLA-g-GMA and MAP exhibited cytocompatibility with fibroblasts. • PLA-g-GMA/MAP composites exhibited mechanical properties superior to PLA/MAP. • PLA-g-GMA/MAP composites were more processable than PLA/MAP.

Improvement of cytocompatibility of polylactide by filling with marine algae powder

International Nuclear Information System (INIS)

Wu, Tung-Yi; Yang, Ming-Chien; Hsu, Yi-Chiang

2015-01-01

This work evaluated the cytocompatibility, thermal and mechanical properties of composites of polylactide (PLA) and marine algae powder (MAP). To improve the thermal and mechanical properties of PLA–MAP composites, glycidyl methacrylate (GMA) was used as the compatibilizer for the blending of PLA and MAP. The PLA-g-GMA/MAP composites exhibited superior mechanical properties, attributing to higher compatibility between the polymer and MAP, comparing to PLA/MAP composites. The dispersion of MAP in the PLA-g-GMA matrix was highly homogeneous as a result of etherification. The lower melt torque of the PLA-g-GMA/MAP composites also made them more processable than PLA/MAP. To assess the cytocompatibility, normal human foreskin fibroblasts (FBs) were seeded onto each type of the composites. Results of FB proliferation, collagen production, and cytotoxicity assays indicated greater cytocompatibility for the PLA/MAP composites than for the PLA-g-GMA/MAP composites. Furthermore, both PLA/MAP and PLA-g-GMA/MAP composites were more cytocompatible than pure PLA. - Highlights: • PLA was grafted with GMA to form ether bond with marine algae powder (MAP). • Composites of PLA-g-GMA and MAP exhibited cytocompatibility with fibroblasts. • PLA-g-GMA/MAP composites exhibited mechanical properties superior to PLA/MAP. • PLA-g-GMA/MAP composites were more processable than PLA/MAP

Contrasting ability to take up leucine and thymidine among freshwater bacterial groups: implications for bacterial production measurements

Science.gov (United States)

Pérez, María Teresa; Hörtnagl, Paul; Sommaruga, Ruben

2010-01-01

We examined the ability of different freshwater bacterial groups to take up leucine and thymidine in two lakes. Utilization of both substrates by freshwater bacteria was examined at the community level by looking at bulk incorporation rates and at the single-cell level by combining fluorescent in situ hybridization and signal amplification by catalysed reporter deposition with microautoradiography. Our results showed that leucine was taken up by 70–80% of Bacteria-positive cells, whereas only 15–43% of Bacteria-positive cells were able to take up thymidine. When a saturating substrate concentration in combination with a short incubation was used, 80–90% of Betaproteobacteria and 67–79% of Actinobacteria were positive for leucine uptake, whereas thymidine was taken up by bacterial group. Bacterial abundance was a good predictor of the relative contribution of bacterial groups to leucine uptake, whereas when thymidine was used Actinobacteria represented the large majority (> 80%) of the cells taking up this substrate. Increasing the substrate concentration to 100 nM did not affect the percentage of R-BT cells taking up leucine (> 90% even at low concentrations), but moderately increased the fraction of thymidine-positive R-BT cells to a maximum of 35% of the hybridized cells. Our results show that even at very high concentrations, thymidine is not taken up by all, otherwise active, bacterial cells. PMID:19725866

Cytocompatibility and early inflammatory response of human endothelial cells in direct culture with Mg-Zn-Sr alloys

Science.gov (United States)

Cipriano, Aaron F.; Sallee, Amy; Tayoba, Myla; Cortez Alcaraz, Mayra C.; Lin, Alan; Guan, Ren-Guo; Zhao, Zhan-Yong; Liu, Huinan

2018-01-01

Crystalline Mg-Zinc (Zn)-Strontium (Sr) ternary alloys consist of elements naturally present in the human body and provide attractive mechanical and biodegradable properties for a variety of biomedical applications. The first objective of this study was to investigate the degradation and cytocompatibility of four Mg-4Zn-xSr alloys (x = 0.15, 0.5, 1.0, 1.5 wt%; designated as ZSr41A, B, C, and D respectively) in the direct culture with human umbilical vein endothelial cells (HUVEC) in vitro. The second objective was to investigate, for the first time, the early-stage inflammatory response in cultured HUVECs as indicated by the induction of vascular cellular adhesion molecule-1 (VCAM-1). The results showed that the 24-h in vitro degradation of the ZSr41 alloys containing a β-phase with a Zn/Sr at% ratio ~1.5 was significantly faster than the ZSr41 alloys with Zn/Sr at% ~1. Additionally, the adhesion density of HUVECs in the direct culture but not in direct contact with the ZSr41 alloys for up to 24 h was not adversely affected by the degradation of the alloys. Importantly, neither culture media supplemented with up to 27.6 mM Mg2+ ions nor media intentionally adjusted up to alkaline pH 9 induced any detectable adverse effects on HUVEC responses. In contrast, the significantly higher, yet non-cytotoxic, Zn2+ ion concentration from the degradation of ZSr41D alloy was likely the cause for the initially higher VCAM-1 expression on cultured HUVECs. Lastly, analysis of the HUVEC-ZSr41 interface showed near-complete absence of cell adhesion directly on the sample surface, most likely caused by either a high local alkalinity, change in surface topography, and/or surface composition. The direct culture method used in this study was proposed as a valuable tool for studying the design aspects of Zn-containing Mg-based biomaterials in vitro, in order to engineer solutions to address current shortcomings of Mg alloys for vascular device applications. PMID:27746360

Physicochemical properties and in vitro cytocompatibility of modified titanium surfaces prepared via micro-arc oxidation with different calcium concentrations

International Nuclear Information System (INIS)

Wu, Sui-Dan; Zhang, Hui; Dong, Xu-Dong; Ning, Cheng-Yun; Fok, Alex S.L.; Wang, Yan

2015-01-01

Highlights: • MAO coating improves the surface characteristics and cytocompatibility of titanium. • Composition of MAO coating varies with the electrolyte concentration. • MAO coating properties can be optimized by adjusting the electrolyte concentration. • Higher CA concentration contributes to more favorable MAO coating cytocompatibility. - Abstract: Objective: To explore the effect of calcium concentration in the electrolyte solution on the physicochemical properties and biocompatibility of coatings formed by micro-arc oxidation (MAO) on titanium surfaces. Methods: The surfaces of pure titanium plates were modified by MAO in an electrolytic solution containing calcium acetate (CA; C 4 H 6 CaO 4 ) at concentrations of 0.05, 0.1, 0.2, or 0.3 M and β-glycerophosphate disodium salt pentahydrate (β-GP; C 3 H 7 Na 2 O 6 P·5H 2 O) at a fixed concentration of 0.02 M. Surface topography, elemental characteristics, phase composition, and roughness were investigated by scanning electron microscopy, energy-dispersive X-ray analysis, X-ray diffraction, and a surface roughness tester, respectively. To assess the cytocompatibility and osteoinductivity of the surfaces, MC3T3-E1 preosteoblasts were cultured on the surfaces in vitro, and cell morphology, adhesion, proliferation, and differentiation were observed. Results: The porous MAO coating was composed primarily of TiO 2 rutile and anatase. The amount of TiO 2 rutile, the Ca/P ratio, and the surface roughness of the MAO coating increased with increasing CA concentration in the electrolyte solution. Ca 3 (PO 4 ) 2 , CaCO 3 , and CaTiO 3 were formed on MAO-treated surfaces prepared with CA concentrations of 0.2 and 0.3 M. Cell proliferation and differentiation increased with increasing CA concentration, with MC3T3-E1 cells exhibiting favorable morphologies for bone–implant integration. Conclusions: MAO coating improves the surface characteristics and cytocompatibility of titanium for osseointegration. Higher CA

Cytocompatibility of Siloxane-Containing Vaterite/Poly(l-lactic acid) Composite Coatings on Metallic Magnesium.

Science.gov (United States)

Yamada, Shinya; Maeda, Hirotaka; Obata, Akiko; Lohbauer, Ulrich; Yamamoto, Akiko; Kasuga, Toshihiro

2013-12-12

Poly(l-lactic acid)-based films which include 60 wt % of vaterite (V) or siloxane-containing vaterite (SiV) were coated on a pure magnesium substrate, denoted by PLLA/V or PLLA/SiV, respectively, to suppress early corrosion and improve its cytocompatibility. Both coating films adhered to the Mg substrate with 2.3-2.8 MPa of tensile bonding strength. Soaking test for 7 days in α-modified minimum essential medium revealed that the morphological instability of the PLLA/V film caused a higher amount of Mg 2+ ion to be released from the coating sample. On the other hand, in the case of the coating with the PLLA/SiV film, no morphological change even after the soaking test was observed, owing to the suppression of the degradation rate. In cell culture tests, the proliferation of mouse osteoblast-like cell (MC3T3-E1) was significantly enhanced by both coatings, in comparison with the uncoated magnesium substrate. The cell morphology revealed that a few less-spread cells were observed on the PLLA/V film, while more elongated cells were done on the PLLA/SiV film. The cells on the PLLA/SiV film exhibited an extremely higher alkaline phosphatase activity after 21 days of incubation than that on the PLLA/V one. The PLLA/SiV film suppressed the early corrosion and enhanced cytocompatibility on metallic magnesium.

Cytocompatibility of Siloxane-Containing Vaterite/Poly(l-lactic acid Composite Coatings on Metallic Magnesium

Directory of Open Access Journals (Sweden)

Shinya Yamada

2013-12-01

Full Text Available Poly(l-lactic acid-based films which include 60 wt % of vaterite (V or siloxane-containing vaterite (SiV were coated on a pure magnesium substrate, denoted by PLLA/V or PLLA/SiV, respectively, to suppress early corrosion and improve its cytocompatibility. Both coating films adhered to the Mg substrate with 2.3–2.8 MPa of tensile bonding strength. Soaking test for 7 days in α-modified minimum essential medium revealed that the morphological instability of the PLLA/V film caused a higher amount of Mg2+ ion to be released from the coating sample. On the other hand, in the case of the coating with the PLLA/SiV film, no morphological change even after the soaking test was observed, owing to the suppression of the degradation rate. In cell culture tests, the proliferation of mouse osteoblast-like cell (MC3T3-E1 was significantly enhanced by both coatings, in comparison with the uncoated magnesium substrate. The cell morphology revealed that a few less-spread cells were observed on the PLLA/V film, while more elongated cells were done on the PLLA/SiV film. The cells on the PLLA/SiV film exhibited an extremely higher alkaline phosphatase activity after 21 days of incubation than that on the PLLA/V one. The PLLA/SiV film suppressed the early corrosion and enhanced cytocompatibility on metallic magnesium.

Dendritic cells take up and present antigens from viable and apoptotic polymorphonuclear leukocytes.

Directory of Open Access Journals (Sweden)

Carlos Alfaro

Full Text Available Dendritic cells (DC are endowed with the ability to cross-present antigens from other cell types to cognate T cells. DC are poised to meet polymorphonuclear leukocytes (PMNs as a result of being co-attracted by interleukin-8 (IL-8, for instance as produced by tumor cells or infected tissue. Human monocyte-derived and mouse bone marrow-derived DC can readily internalize viable or UV-irradiated PMNs. Such internalization was abrogated at 4°C and partly inhibited by anti-CD18 mAb. In mice, DC which had internalized PMNs containing electroporated ovalbumin (OVA protein, were able to cross-present the antigen to CD8 (OT-1 and CD4 (OT-2 TCR-transgenic T cells. Moreover, in humans, tumor cell debris is internalized by PMNs and the tumor-cell material can be subsequently taken up from the immunomagnetically re-isolated PMNs by DC. Importantly, if human neutrophils had endocytosed bacteria, they were able to trigger the maturation program of the DC. Moreover, when mouse PMNs with E. coli in their interior are co-injected in the foot pad with DC, many DC loaded with fluorescent material from the PMNs reach draining lymph nodes. Using CT26 (H-2(d mouse tumor cells, it was observed that if tumor cells are intracellularly loaded with OVA protein and UV-irradiated, they become phagocytic prey of H-2(d PMNs. If such PMNs, that cannot present antigens to OT-1 T cells, are immunomagnetically re-isolated and phagocytosed by H-2(b DC, such DC productively cross-present OVA antigen determinants to OT-1 T cells. Cross-presentation to adoptively transferred OT-1 lymphocytes at draining lymph nodes also take place when OVA-loaded PMNs (H-2(d are coinjected in the footpad of mice with autologous DC (H-2(b. In summary, our results indicate that antigens phagocytosed by short-lived PMNs can be in turn internalized and productively cross-presented by DC.

Improved Mechanical Compatibility and Cytocompatibility of Ta/Ti Double-Layered Composite Coating

Science.gov (United States)

Ding, Ding; Xie, Youtao; Li, Kai; Huang, Liping; Zheng, Xuebin

2017-08-01

In order to improve the mechanical compatibility and cytocompatibility of titanium implants, a composite coating with double layers composed of tantalum and titanium was designed and prepared using plasma spraying technology. In the composite coating, the upper tantalum layer provides a good biocompatibility, and the sublayer of titanium with a porous structure ensures the low elastic modulus. Results show that the fabricated composite coating exhibits a relatively low elastic modulus of 26.7 GPa, which is close to the elastic modulus of human cortical bone. In vitro cytocompatibility evaluation of the composite coating shows that the human bone marrow stromal cells exhibit enhanced adhesion and spreading performance on the double-layered composite coating in comparison with the single-layered titanium coating. In order to eliminate the misgivings of chemical stability of the composite coating in clinical application, electrochemical corrosion of the coating was examined. The results obtained revealed a very weak galvanic corrosion between the tantalum and titanium in the composite coating, which would ensure the safety of the coating in vivo.

Properties and osteoblast cytocompatibility of self-curing acrylic cements modified by glass fillers.

Science.gov (United States)

Lopes, P; Garcia, M P; Fernandes, M H; Fernandes, M H V

2013-11-01

Materials filled with a silicate glass (MSi) and a borate glass (MB) were developed and compared in terms of their in vitro behavior. The effect of filler composition and concentration (0, 30, 40 and 50 wt%) on the curing parameters, residual monomer, water uptake, weight loss, bioactivity, mechanical properties (bending and compression) and osteoblast cytocompatibility was evaluated. The addition of bioactive glass filler significantly improved the cements curing parameters and the mechanical properties. The most relevant results were obtained for the lower filler concentration (30 t%) a maximum flexural strength of 40.4 Pa for MB3 and a maximum compressive strength of 95.7 MPa for MSi3. In vitro bioactivity in acellular media was enhanced by the higher glass contents in the cements. Regarding the biological assessment, the incorporation of the silicate glass significantly improved osteoblast cytocompatibility, whereas the presence of the borate glass resulted in a poor cell response. Nevertheless it was shown that the surviving cells on the MB surface were in a more differentiated stage compared to those growing over non-filled poly(methyl methacrylate). Results suggest that the developed formulations offer a high range of properties that might be interesting for their use as self-curing cements.

In vitro haematic proteins adsorption and cytocompatibility study on acrylic copolymer to realise coatings for drug-eluting stents

International Nuclear Information System (INIS)

Gagliardi, Mariacristina

2012-01-01

In the present paper, a preliminary in vitro analysis of biocompatibility of newly-synthesised acrylic copolymers is reported. In particular, with the aim to obtain coatings for drug-eluting stents, blood protein absorption and cytocompatibility were studied. For protein absorption tests, bovine serum albumin and bovine plasma fibrinogen were considered. Cytocompatibility was tested using C2C12 cell line as model, analysing the behaviour of polymeric matrices and of drug-eluting systems, obtained loading polymeric matrices with paclitaxel, an anti-mitotic drug, in order to evaluate the efficacy of a pharmacological treatment locally administered from these materials. Results showed that the amount of albumin absorbed was greater than the amount of fibrinogen (comprised in the range of 70%–85% and 10%–22% respectively) and it is a good behaviour in terms of haemocompatibility. Cell culture tests showed good adhesion properties and a relative poor proliferation. In addition, a strong effect related to drug elution and a correlation with the macromolecular composition were detected. In this preliminary analysis, tested materials showed good characteristics and can be considered possible candidates to obtain coatings for drug-eluting stents. Highlights: ► Preliminary evaluation of haemo- and cytocompatibility of newly-synthesised acrylic copolymers ► Materials adsorb higher amounts of albumin and with a faster rate than fibrinogen. ► Protein adsorption depended on the macromolecular composition and surface properties. ► Cell viability on pure samples and efficacy of paclitaxel release were verified in C2C12 cultures.

In vitro haematic proteins adsorption and cytocompatibility study on acrylic copolymer to realise coatings for drug-eluting stents

Energy Technology Data Exchange (ETDEWEB)

Gagliardi, Mariacristina, E-mail: mariacristina.gagliardi@iit.it

2012-12-01

In the present paper, a preliminary in vitro analysis of biocompatibility of newly-synthesised acrylic copolymers is reported. In particular, with the aim to obtain coatings for drug-eluting stents, blood protein absorption and cytocompatibility were studied. For protein absorption tests, bovine serum albumin and bovine plasma fibrinogen were considered. Cytocompatibility was tested using C2C12 cell line as model, analysing the behaviour of polymeric matrices and of drug-eluting systems, obtained loading polymeric matrices with paclitaxel, an anti-mitotic drug, in order to evaluate the efficacy of a pharmacological treatment locally administered from these materials. Results showed that the amount of albumin absorbed was greater than the amount of fibrinogen (comprised in the range of 70%-85% and 10%-22% respectively) and it is a good behaviour in terms of haemocompatibility. Cell culture tests showed good adhesion properties and a relative poor proliferation. In addition, a strong effect related to drug elution and a correlation with the macromolecular composition were detected. In this preliminary analysis, tested materials showed good characteristics and can be considered possible candidates to obtain coatings for drug-eluting stents. Highlights: Black-Right-Pointing-Pointer Preliminary evaluation of haemo- and cytocompatibility of newly-synthesised acrylic copolymers Black-Right-Pointing-Pointer Materials adsorb higher amounts of albumin and with a faster rate than fibrinogen. Black-Right-Pointing-Pointer Protein adsorption depended on the macromolecular composition and surface properties. Black-Right-Pointing-Pointer Cell viability on pure samples and efficacy of paclitaxel release were verified in C2C12 cultures.

Physicochemical properties and in vitro cytocompatibility of modified titanium surfaces prepared via micro-arc oxidation with different calcium concentrations

Energy Technology Data Exchange (ETDEWEB)

Wu, Sui-Dan; Zhang, Hui [Guanghua School of Stomatology, Hospital of Stomatology, Guangdong Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou 510055 (China); Dong, Xu-Dong [Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, BC V6T 1Z3 (Canada); Ning, Cheng-Yun [College of Material Science and Engineering, South China University of Technology, Guangzhou 510641 (China); Fok, Alex S.L. [Minnesota Dental Research Center of Biomaterials and Biomechanics, School of Dentistry, University of Minnesota, Minneapolis, MN 55414 (United States); Wang, Yan, E-mail: wyan65@163.com [Guanghua School of Stomatology, Hospital of Stomatology, Guangdong Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou 510055 (China)

2015-02-28

Highlights: • MAO coating improves the surface characteristics and cytocompatibility of titanium. • Composition of MAO coating varies with the electrolyte concentration. • MAO coating properties can be optimized by adjusting the electrolyte concentration. • Higher CA concentration contributes to more favorable MAO coating cytocompatibility. - Abstract: Objective: To explore the effect of calcium concentration in the electrolyte solution on the physicochemical properties and biocompatibility of coatings formed by micro-arc oxidation (MAO) on titanium surfaces. Methods: The surfaces of pure titanium plates were modified by MAO in an electrolytic solution containing calcium acetate (CA; C{sub 4}H{sub 6}CaO{sub 4}) at concentrations of 0.05, 0.1, 0.2, or 0.3 M and β-glycerophosphate disodium salt pentahydrate (β-GP; C{sub 3}H{sub 7}Na{sub 2}O{sub 6}P·5H{sub 2}O) at a fixed concentration of 0.02 M. Surface topography, elemental characteristics, phase composition, and roughness were investigated by scanning electron microscopy, energy-dispersive X-ray analysis, X-ray diffraction, and a surface roughness tester, respectively. To assess the cytocompatibility and osteoinductivity of the surfaces, MC3T3-E1 preosteoblasts were cultured on the surfaces in vitro, and cell morphology, adhesion, proliferation, and differentiation were observed. Results: The porous MAO coating was composed primarily of TiO{sub 2} rutile and anatase. The amount of TiO{sub 2} rutile, the Ca/P ratio, and the surface roughness of the MAO coating increased with increasing CA concentration in the electrolyte solution. Ca{sub 3}(PO{sub 4}){sub 2}, CaCO{sub 3}, and CaTiO{sub 3} were formed on MAO-treated surfaces prepared with CA concentrations of 0.2 and 0.3 M. Cell proliferation and differentiation increased with increasing CA concentration, with MC3T3-E1 cells exhibiting favorable morphologies for bone–implant integration. Conclusions: MAO coating improves the surface characteristics and

Cytocompatibility of a silk fibroin tubular scaffold

International Nuclear Information System (INIS)

Wang, Jiannan; Wei, Yali; Yi, Honggen; Liu, Zhiwu; Sun, Dan; Zhao, Huanrong

2014-01-01

Regenerated silk fibroin (SF) materials are increasingly used for tissue engineering applications. In order to explore the feasibility of a novel biomimetic silk fibroin tubular scaffold (SFTS) crosslinked by poly(ethylene glycol) diglycidyl ether (PEG-DE), biocompatibility with cells was evaluated. The novel biomimetic design of the SFTS consisted of three distinct layers: a regenerated SF intima, a silk braided media and a regenerated SF adventitia. The SFTS exhibited even silk fibroin penetration throughout the braid, forming a porous layered tube with superior mechanical, permeable and cell adhesion properties that are beneficial to vascular regeneration. Cytotoxicity and cell compatibility were tested on L929 cells and human umbilical vein endothelial cells (EA.hy926). DNA content analysis, scanning electron and confocal microscopies and MTT assay showed no inhibitory effects on DNA replication. Cell morphology, viability and proliferation were good for L929 cells, and satisfactory for EA.hy926 cells. Furthermore, the suture retention strength of the SFTS was about 23 N and the Young's modulus was 0.2–0.3 MPa. Collectively, these data demonstrate that PEG-DE crosslinked SFTS possesses the appropriate cytocompatibility and mechanical properties for use as vascular scaffolds as an alternative to vascular autografts. - Highlights: • A PEG-DE cross-linked small caliber porous silk fibroin tubular scaffold (SFTS) • PEG-DE cross-linked SF film had no inhibitory effect on DNA replication of cells. • Cells cultured on the SFTS showed good morphology, cell viability and proliferative activity. • SFTS would be beneficial to endothelialization. • SFTS had good suture retention strength and flexibility

Anticorrosive effects and in vitro cytocompatibility of calcium silicate/zinc-doped hydroxyapatite composite coatings on titanium

Energy Technology Data Exchange (ETDEWEB)

Huang, Yong, E-mail: xfpang@aliyun.com [College of Lab Medicine, Hebei North University, Zhangjiakou 075000 (China); Institute of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 610054 (China); Zhang, Honglei [College of Chemistry Environmental Science, Hebei University, Baoding 071000 (China); Qiao, Haixia; Nian, Xiaofeng [College of Lab Medicine, Hebei North University, Zhangjiakou 075000 (China); Zhang, Xuejiao, E-mail: 527238610@qq.com [College of Lab Medicine, Hebei North University, Zhangjiakou 075000 (China); Wang, Wendong; Zhang, Xiaoyun; Chang, Xiaotong [College of Lab Medicine, Hebei North University, Zhangjiakou 075000 (China); Han, Shuguang [Institute of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 610054 (China); Pang, Xiaofeng [Institute of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 610054 (China); International Centre for Materials Physics, Chinese Academy of Science, Shenyang 110015 (China)

2015-12-01

Highlights: • We developed a ZnHA/CS-coated Ti implant by using an ED method. • The obtained ZnHA/CS coatings presented a net-like micro-porous. • The ZnHA/CS coating possessed an excellent corrosion protection ability. • The composite coated CP-Ti possesses favourable cytocompatibility. - Abstract: This work elucidated the corrosion resistance and cytocompatibility of electroplated Zn- and Si-containing bioactive calcium silicate/zinc-doped hydroxyapatite (ZnHA/CS) ceramic coatings on commercially pure titanium (CP-Ti). The formation of ZnHA/CS coating was investigated through Fourier transform infrared spectroscopy, X-ray diffraction (XRD), scanning electron microscopy, energy dispersive X-ray and inductively coupled plasma analyses. The XRD image showed that the reaction layer was mainly composed of HA and CaSiO{sub 3}. The fabricated ZnHA/CS coatings presented a porous structure and appropriate thickness for possible applications in orthopaedic surgery. Potentiodynamic polarization tests showed that ZnHA/CS coatings exhibited higher corrosion resistance than CP-Ti. Dissolution tests on the coating also revealed that Si{sup 4+} and Zn{sup 2+} were leached at low levels. Moreover, MC3T3-E1 cells cultured on ZnHA/CS featured improved cell morphology, adhesion, spreading, proliferation and expression of alkaline phosphatase than those cultured on HA. The high cytocompatibility of ZnHA/CS could be mainly attributed to the combination of micro-porous surface effects and ion release (Zn{sup 2+} and Si{sup 4+}). All these results indicate that ZnHA/CS composite-coated CP-Ti may be a potential material for orthopaedic applications.

Nanocomposites of high-density polyethylene with amorphous calcium phosphate: in vitro biomineralization and cytocompatibility of human mesenchymal stem cells

International Nuclear Information System (INIS)

Hild, Nora; Fuhrer, Roland; Mohn, Dirk; Bubenhofer, Stephanie B; Grass, Robert N; Luechinger, Norman A; Stark, Wendelin J; Feldman, Kirill; Dora, Claudio

2012-01-01

Polyethylene is widely used as a component of implants in medicine. Composites made of high-density polyethylene (HDPE) containing different amounts of amorphous calcium phosphate nanoparticles were investigated concerning their in vitro biomedical performance. The nanoparticles were produced by flame spray synthesis and extruded with HDPE, the latter complying with Food and Drug Administration regulations. Mechanical properties such as Young's modulus and contact angle as well as in vitro biomineralization of the nanocomposites hot-pressed into thin films were evaluated. The deposition of a hydroxyapatite layer occurred upon immersion in simulated body fluid. Additionally, a cell culture study with human mesenchymal stem cells for six weeks allowed a primary assessment of the cytocompatibility. Viability assays (alamarBlue and lactate dehydrogenase detection) proved the absence of cytotoxic effects of the scaffolds. Microscopic images after hematoxylin and eosin staining confirmed typical growth and morphology. A preliminary experiment analyzed the alkaline phosphatase activity after two weeks. These findings motivate further investigations on bioactive HDPE in bone tissue engineering. (paper)

Nanocomposites of high-density polyethylene with amorphous calcium phosphate: in vitro biomineralization and cytocompatibility of human mesenchymal stem cells.

Science.gov (United States)

Hild, Nora; Fuhrer, Roland; Mohn, Dirk; Bubenhofer, Stephanie B; Grass, Robert N; Luechinger, Norman A; Feldman, Kirill; Dora, Claudio; Stark, Wendelin J

2012-10-01

Polyethylene is widely used as a component of implants in medicine. Composites made of high-density polyethylene (HDPE) containing different amounts of amorphous calcium phosphate nanoparticles were investigated concerning their in vitro biomedical performance. The nanoparticles were produced by flame spray synthesis and extruded with HDPE, the latter complying with Food and Drug Administration regulations. Mechanical properties such as Young's modulus and contact angle as well as in vitro biomineralization of the nanocomposites hot-pressed into thin films were evaluated. The deposition of a hydroxyapatite layer occurred upon immersion in simulated body fluid. Additionally, a cell culture study with human mesenchymal stem cells for six weeks allowed a primary assessment of the cytocompatibility. Viability assays (alamarBlue and lactate dehydrogenase detection) proved the absence of cytotoxic effects of the scaffolds. Microscopic images after hematoxylin and eosin staining confirmed typical growth and morphology. A preliminary experiment analyzed the alkaline phosphatase activity after two weeks. These findings motivate further investigations on bioactive HDPE in bone tissue engineering.

Long-term antibacterial characteristics and cytocompatibility of titania nanotubes loaded with Au nanoparticles without photocatalytic effects

Energy Technology Data Exchange (ETDEWEB)

Wang, Guomin [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China); Feng, Hongqing, E-mail: fenghongqing@binn.cas.cn [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China); Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, National Center for Nanoscience and Technology (NCNST), Beijing 100083 (China); Jin, Weihong; Gao, Ang; Peng, Xiang; Li, Wan; Wu, Hao [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China); Li, Zhou [Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, National Center for Nanoscience and Technology (NCNST), Beijing 100083 (China); Chu, Paul K., E-mail: paul.chu@cityu.edu.hk [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China)

2017-08-31

Highlights: • Au@TiO{sub 2}-NT shows long-term antibacterial effects without photocatalytical effects. • An ROS-free antibacterial process is confirmed. • Au@TiO{sub 2}-NT shows good compatibility with osteoblasts and does not induce ROS production. - Abstract: Au nanoparticles (NPs) can endow titania nanotubes (Au@TiO{sub 2}-NT) with light-independent antibacterial properties which bode well for in vivo application because of the dark environment inside tissues. In this work, the long-term antibacterial bactericidal properties and cytocompatibility of Au@TiO{sub 2}-NT without photocatalytic effects are studied in details. The materials exhibit antibacterial effects against Staphylococcus aureus according to antibacterial tests carried out for a total time of 21 days, which are normally long enough for early stage tissue healing after surgery. In addition, adhesion and proliferation of MC3T3-E1 osteoblasts on Au@TiO{sub 2}-NT reveal cytocompatibility comparable to that of TiO{sub 2}-NT. No reactive oxygen species (ROS) are detected from either the bacteria or MC3T3-E1 cells cultured on the Au@TiO{sub 2}-NT surface. The absence of ROS, long-term antibacterial properties, and cytocompatibility make Au@TiO{sub 2}-NT promising biomaterials in orthopedic devices and implants.

Mechanical, degradation and cytocompatibility properties of magnesium coated phosphate glass fibre reinforced polycaprolactone composites.

Science.gov (United States)

Liu, Xiaoling; Hasan, Muhammad S; Grant, David M; Harper, Lee T; Parsons, Andrew J; Palmer, Graham; Rudd, Chris D; Ahmed, Ifty

2014-11-01

Retention of mechanical properties of phosphate glass fibre reinforced degradable polyesters such as polycaprolactone and polylactic acid in aqueous media has been shown to be strongly influenced by the integrity of the fibre/polymer interface. A previous study utilising 'single fibre' fragmentation tests found that coating with magnesium improved the fibre and matrix interfacial shear strength. Therefore, the aim of this study was to investigate the effects of a magnesium coating on the manufacture and characterisation of a random chopped fibre reinforced polycaprolactone composite. Short chopped strand non-woven phosphate glass fibre mats were sputter coated with degradable magnesium to manufacture phosphate glass fibre/polycaprolactone composites. The degradation behaviour (water uptake, mass loss and pH change of the media) of these polycaprolactone composites as well as of pure polycaprolactone was investigated in phosphate buffered saline. The Mg coated fibre reinforced composites revealed less water uptake and mass loss during degradation compared to the non-coated composites. The cations released were also explored and a lower ion release profile for all three cations investigated (namely Na(+), Mg(2+) and Ca(2+)) was seen for the Mg coated composite samples. An increase of 17% in tensile strength and 47% in tensile modulus was obtained for the Mg coated composite samples. Both flexural and tensile properties were investigated and a higher retention of mechanical properties was obtained for the Mg coated fibre reinforced composite samples up to 10 days immersion in PBS. Cytocompatibility study showed both composite samples (coated and non-coated) had good cytocompatibility with human osteosarcoma cell line. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

In Vitro Corrosion and Cytocompatibility of ZK60 Magnesium Alloy Coated with Hydroxyapatite by a Simple Chemical Conversion Process for Orthopedic Applications

Science.gov (United States)

Wang, Bing; Huang, Ping; Ou, Caiwen; Li, Kaikai; Yan, Biao; Lu, Wei

2013-01-01

Magnesium and its alloys—a new class of degradable metallic biomaterials—are being increasingly investigated as a promising alternative for medical implant and device applications due to their advantageous mechanical and biological properties. However, the high corrosion rate in physiological environments prevents the clinical application of Mg-based materials. Therefore, the objective of this study was to develop a hydroxyapatite (HA) coating on ZK60 magnesium alloy substrates to mediate the rapid degradation of Mg while improving its cytocompatibility for orthopedic applications. A simple chemical conversion process was applied to prepare HA coating on ZK60 magnesium alloy. Surface morphology, elemental compositions, and crystal structures were characterized using scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction, respectively. The corrosion properties of samples were investigated by immersion test and electrochemical test. Murine fibroblast L-929 cells were harvested and cultured with coated and non-coated ZK60 samples to determine cytocompatibility. The degradation results suggested that the HA coatings decreased the degradation of ZK60 alloy. No significant deterioration in compression strength was observed for all the uncoated and coated samples after 2 and 4 weeks’ immersion in simulated body fluid (SBF). Cytotoxicity test indicated that the coatings, especially HA coating, improved cytocompatibility of ZK60 alloy for L929 cells. PMID:24300096

Influence of biodegradable polymer coatings on corrosion, cytocompatibility and cell functionality of Mg-2.0Zn-0.98Mn magnesium alloy.

Science.gov (United States)

Witecka, Agnieszka; Yamamoto, Akiko; Idaszek, Joanna; Chlanda, Adrian; Święszkowski, Wojciech

2016-08-01

Four kinds of biodegradable polymers were employed to prepare bioresorbable coatings on Mg-2.0Zn-0.98Mn (ZM21) alloy to understand the relationship between polymer characteristics, protective effects on substrate corrosion, cytocompatibility and cell functionality. Poly-l-lactide (PLLA), poly(3-hydroxybutyrate) (PHB), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) or poly(lactic-co-glycolic) acid (PLGA) was spin-coated on ZM21, obtaining a smooth, non-porous coating less than 0.5μm in thickness. Polymer coating characterization, a degradation study, and biocompatibility evaluations were performed. After 4 w of immersion into cell culture medium, degradation of PLGA and PLLA coatings were confirmed by ATR-FTIR observation. The coatings of PLLA, PHB and PHBV, which have lower water permeability and slower degradation than PLGA, provide better suppression of initial ZM21 degradation and faster promotion of human osteosarcoma cell growth and differentiation. Copyright © 2016 Elsevier B.V. All rights reserved.

Pyrolytic carbon coating for cytocompatibility of titanium oxide nanoparticles: a promising candidate for medical applications

International Nuclear Information System (INIS)

Behzadi, Shahed; Simchi, Abdolreza; Imani, Mohammad; Yousefi, Mohammad; Galinetto, Pietro; Amiri, Houshang; Stroeve, Pieter; Mahmoudi, Morteza

2012-01-01

Nanoparticles for biomedical use must be cytocompatible with the biological environment that they are exposed to. Current research has focused on the surface functionalization of nanoparticles by using proteins, polymers, thiols and other organic compounds. Here we show that inorganic nanoparticles such as titanium oxide can be coated by pyrolytic carbon (PyC) and that the coating has cytocompatible properties. Pyrolization and condensation of methane formed a thin layer of pyrolytic carbon on the titanium oxide core. The formation of the PyC shell retards coalescence and sintering of the ceramic phase. Our MTT assay shows that the PyC-coated particles are cytocompatible at employed doses. (paper)

Antimicrobial Properties and Cytocompatibility of PLGA/Ag Nanocomposites

Directory of Open Access Journals (Sweden)

Mariangela Scavone

2016-01-01

Full Text Available The purpose of this study was to investigate the antimicrobial properties of multifunctional nanocomposites based on poly(dl-Lactide-co-Glycolide (PLGA and increasing concentration of silver (Ag nanoparticles and their effects on cell viability for biomedical applications. PLGA nanocomposite films, produced by solvent casting with 1 wt%, 3 wt% and 7 wt% of Ag nanoparticles were investigated and surface properties were characterized by atomic force microscopy and contact angle measurements. Antibacterial tests were performed using an Escherichia coli RB and Staphylococcus aureus 8325-4 strains. The cell viability and morphology were performed with a murine fibroblast cell line (L929 and a human osteosarcoma cell line (SAOS-2 by cell viability assay and electron microscopy observations. Matrix protein secretion and deposition were also quantified by enzyme-linked immunosorbent assay (ELISA. The results suggest that the PLGA film morphology can be modified introducing a small percentage of silver nanoparticles, which induce the onset of porous round-like microstructures and also affect the wettability. The PLGA/Ag films having silver nanoparticles of more than 3 wt% showed antibacterial effects against E. coli and S. aureus. Furthermore, silver-containing PLGA films displayed also a good cytocompatibility when assayed with L929 and SAOS-2 cells; indicating the PLGA/3Ag nanocomposite film as a promising candidate for tissue engineering applications.

Cytocompatible and water stable ultrafine protein fibers for tissue engineering

Science.gov (United States)

Jiang, Qiuran

This dissertation proposal focuses on the development of cytocompatible and water stable protein ultrafine fibers for tissue engineering. The protein-based ultrafine fibers have the potential to be used for biomedicine, due to their biocompatibility, biodegradability, similarity to natural extracellular matrix (ECM) in physical structure and chemical composition, and superior adsorption properties due to their high surface to volume ratio. However, the current technologies to produce the protein-based ultrafine fibers for biomedical applications still have several problems. For instance, the current electrospinning and phase separation technologies generate scaffolds composed of densely compacted ultrafine fibers, and cells can spread just on the surface of the fiber bulk, and hardly penetrate into the inner sections of scaffolds. Thus, these scaffolds can merely emulate the ECM as a two dimensional basement membrane, but are difficult to mimic the three dimensional ECM stroma. Moreover, the protein-based ultrafine fibers do not possess sufficient water stability and strength for biomedical applications, and need modifications such as crosslinking. However, current crosslinking methods are either high in toxicity or low in crosslinking efficiency. To solve the problems mentioned above, zein, collagen, and gelatin were selected as the raw materials to represent plant proteins, animal proteins, and denatured proteins in this dissertation. A benign solvent system was developed specifically for the fabrication of collagen ultrafine fibers. In addition, the gelatin scaffolds with a loose fibrous structure, high cell-accessibility and cell viability were produced by a novel ultralow concentration phase separation method aiming to simulate the structure of three dimensional (3D) ECM stroma. Non-toxic crosslinking methods using citric acid as the crosslinker were also developed for electrospun or phase separated scaffolds from these three proteins, and proved to be

Preparation, mechanical properties and in vitro cytocompatibility of multi-walled carbon nanotubes/poly(etheretherketone) nanocomposites.

Science.gov (United States)

Cao, Jianfei; Lu, Yue; Chen, Hechun; Zhang, Lifang; Xiong, Chengdong

2018-03-01

Desired bone repair material must have excellent biocompatibility and high bioactivity. Moreover, mechanical properties of biomaterial should be equivalent to those of human bones. For developing an alternative biocomposite for load-bearing orthopedic application, combination of bioactive fillers with polymer matrix is a feasible approach. In this study, a series of multi-walled carbon nanotubes (MWCNTs)/poly(etheretherketone) (PEEK) bioactive nanocomposites were prepared by a novel coprecipitation-compounding and injection-molding process. Scanning electron microscope (SEM) images revealed that MWCNTs were adsorbed on the surface of PEEK particles during the coprecipitation-compounding process and dispersed homogeneously in the nanocomposite because the conjugated PEEK polymers stabilized MWCNTs by forming strong π-π stack interactions. The mechanical testing revealed that mechanical performance of PEEK was significantly improved by adding MWCNTs (2-8 wt%) and the experimental values obtained were close to or higher than that of human cortical bone. In addition, incorporation of MWCNTs into PEEK matrix also enhanced the roughness and hydrophilicity of the nanocomposite surface. In vitro cytocompatibility tests demonstrated that the MWCNTs/PEEK nanocomposite was in favor of cell adhesion and proliferation of MC3T3-E1 osteoblast cells, exhibiting excellent cytocompatibility and biocompatibility. Thus, this MWCNTs/PEEK nanocomposite may be used as a promising bone repair material in orthopedic implants application.

Cytocompatibility of direct water synthesized cadmium selenide quantum dots in colo-205 cells

Energy Technology Data Exchange (ETDEWEB)

Rodriguez-Torres, Marcos R. [Universidad Metropolitana, Nanomaterials Science Laboratory, School of Science and Technology (United States); Velez, Christian; Zayas, Beatriz [Universidad Metropolitana, ChemTox Laboratory, School of Environmental Affairs (United States); Rivera, Osvaldo [Universidad Metropolitana, Nanomaterials Science Laboratory, School of Science and Technology (United States); Arslan, Zikri [Jackson State University, Department of Chemistry (United States); Gonzalez-Vega, Maxine N. [Universidad Metropolitana, Nanomaterials Science Laboratory, School of Science and Technology (United States); Diaz-Diestra, Daysi; Beltran-Huarac, Juan; Morell, Gerardo [University of Puerto Rico, Molecular Science Research Center (United States); Primera-Pedrozo, Oliva M., E-mail: oprimera1@suagm.edu [Universidad Metropolitana, Nanomaterials Science Laboratory, School of Science and Technology (United States)

2015-06-15

Cadmium selenide quantum dots (CdSe QDs), inorganic semiconducting nanocrystals, are alluring increased attraction due to their highly refined chemistry, availability, and super tunable optical properties suitable for many applications in different research areas, such as photovoltaics, light-emitting devices, environmental sciences, and nanomedicine. Specifically, they are being widely used in bio-imaging in contrast to organic dyes due to their high brightness and improved photo-stability, and their ability to tune their absorption and emission spectra upon changing the crystal size. The production of CdSe QDs is mostly assisted by trioctylphosphine oxide compound, which acts as solvent or solubilizing agent and renders the QDs soluble in organic compounds (such as toluene, chloroform, and hexane) that are highly toxic. To circumvent the toxicity-related factor in CdSe QDs, we report the synthesis of CdSe QDs capped with thioglycolic acid (TGA) in an aqueous medium, and their biocompatibility in colo-205 cancer cells. In this study, the [Cd{sup 2+}]/[TGA] ratio was adjusted to 11:1 and the Se concentration (10 and 15 mM) was monitored in order to evaluate its influence on the optical properties and cytocompatibility. QDs resulted to be quite stable in water (after purification) and RPMI cell medium and no precipitation was observed for long contact times, making them appealing for in vitro experiments. The spectroscopy analysis, advanced electron microscopy, and X-ray diffractometry studies indicate that the final products were successfully formed exhibiting an improved optical response. Colo-205 cells being exposed to different concentrations of TGA-capped CdSe QDs for 12, 24, and 48 h with doses ranging from 0.5 to 2.0 mM show high tolerance reaching cell viabilities as high as 93 %. No evidence of cellular apoptotic pathways was observed as pointed out by our Annexin V assays at higher concentrations. Moreover, confocal microscopy analysis conducted to

Influence of modified polyester on the material properties of collagen-based biocomposites and in vitro evaluation of cytocompatibility

Energy Technology Data Exchange (ETDEWEB)

Wu, Chin-San, E-mail: t50008@cc.kyu.edu.tw

2015-03-01

The cytocompatibility of composite materials collagen (Col)/poly(hydroxyalkanoate) (PHA) and collagen/maleic anhydride-grafted PHA (PHA-g-MA) was investigated in this study. Col was homogeneously dispersed in the PHA-g-MA matrix as a result of condensation reactions. Mechanical characterisation indicated that the improved adhesion between Col and PHA-g-MA enhanced the tensile strength of the composite compared with that of PHA/Col. PHA-g-MA/Col composites were also more water-resistant than PHA/Col composites. Collagen and cell proliferation analysis indicated that PHA and PHA-g-MA and their composites were biocompatible with respect to FB proliferation. Cell-cycle and apoptosis assays by FBs on the PHA series composite samples were not affected by DNA content related to damage, i.e. rapid apoptosis/necrosis was not observed, demonstrating the potential of PHA/Col or PHA-g-MA/Col membranes for biomedical material applications. - Highlights: • Composites were prepared using polyester and collagen to explore their cytocompatibility. • The mechanical properties of the composite were significantly enhanced by the use of grafted polyester and collagen. • The polyester and collagen composites facilitated excellent cell viability and collagen production. • The cell cycle was not affected by DNA content related to damage, and it did not lead to rapid apoptosis or necrosis of the cells by the composite.

Influence of modified polyester on the material properties of collagen-based biocomposites and in vitro evaluation of cytocompatibility

International Nuclear Information System (INIS)

Wu, Chin-San

2015-01-01

The cytocompatibility of composite materials collagen (Col)/poly(hydroxyalkanoate) (PHA) and collagen/maleic anhydride-grafted PHA (PHA-g-MA) was investigated in this study. Col was homogeneously dispersed in the PHA-g-MA matrix as a result of condensation reactions. Mechanical characterisation indicated that the improved adhesion between Col and PHA-g-MA enhanced the tensile strength of the composite compared with that of PHA/Col. PHA-g-MA/Col composites were also more water-resistant than PHA/Col composites. Collagen and cell proliferation analysis indicated that PHA and PHA-g-MA and their composites were biocompatible with respect to FB proliferation. Cell-cycle and apoptosis assays by FBs on the PHA series composite samples were not affected by DNA content related to damage, i.e. rapid apoptosis/necrosis was not observed, demonstrating the potential of PHA/Col or PHA-g-MA/Col membranes for biomedical material applications. - Highlights: • Composites were prepared using polyester and collagen to explore their cytocompatibility. • The mechanical properties of the composite were significantly enhanced by the use of grafted polyester and collagen. • The polyester and collagen composites facilitated excellent cell viability and collagen production. • The cell cycle was not affected by DNA content related to damage, and it did not lead to rapid apoptosis or necrosis of the cells by the composite

Development of various composition multicomponent chitosan/fish collagen/glycerin 3D porous scaffolds: Effect on morphology, mechanical strength, biostability and cytocompatibility.

Science.gov (United States)

Ullah, Saleem; Zainol, Ismail; Chowdhury, Shiplu Roy; Fauzi, M B

2018-05-01

The various composition multicomponent chitosan/fish collagen/glycerin 3D porous scaffolds were developed and investigated the effect of various composition chitosan/fish collagen/glycerin on scaffolds morphology, mechanical strength, biostability and cytocompatibility. The scaffolds were fabricated via freeze-drying technique. The effects of various compositions consisting in 3D scaffolds were investigated via FT-IR analysis, porosity, swelling and mechanical tests, and effect on the morphology of scaffolds investigated microscopically. The biostability and cytocompatibility tests were used to explore the ability of scaffolds to use for tissue engineering application. The average pore sizes of scaffolds were in range of 100.73±27.62-116.01±52.06, porosity 71.72±3.46-91.17±2.42%, tensile modulus in dry environment 1.47±0.08-0.17±0.03MPa, tensile modulus in wet environment 0.32±0.03-0.14±0.04MPa and biodegradation rate (at day 30) 60.38±0.70-83.48±0.28%. In vitro culture of human fibroblasts and keratinocytes showed that the various composition multicomponent 3D scaffolds were good cytocompatibility however, the scaffolds contained high amount of fish collagen excellently facilitated cell proliferation and adhesion. It was found that the high amount fish collagen and glycerin scaffolds have high porosity, enough mechanical strength and biostability, and excellent cytocompatibility. Copyright © 2018 Elsevier B.V. All rights reserved.

Development of a Cytocompatible Scaffold from Pig Immature Testicular Tissue Allowing Human Sertoli Cell Attachment, Proliferation and Functionality

Directory of Open Access Journals (Sweden)

Maxime Vermeulen

2018-01-01

Full Text Available Cryopreservation of immature testicular tissue before chemo/radiotherapy is the only option to preserve fertility of cancer-affected prepubertal boys. To avoid reintroduction of malignant cells, development of a transplantable scaffold by decellularization of pig immature testicular tissue (ITT able to support decontaminated testicular cells could be an option for fertility restoration in these patients. We, therefore, compared decellularization protocols to produce a cytocompatible scaffold. Fragments of ITT from 15 piglets were decellularized using three protocols: sodium dodecyl sulfate (SDS-Triton (ST, Triton-SDS-Triton (TST and trypsin 0.05%/ethylenediaminetetraacetic acid (EDTA 0.02%-Triton (TET with varying detergent concentrations. All protocols were able to lower DNA levels. Collagen retention was demonstrated in all groups except ST 1%, and a significant decrease in glycosaminoglycans was observed in the TST 1% and TET 1% groups. When Sertoli cells (SCs were cultured with decellularized tissue, no signs of cytotoxicity were detected. A higher SC proliferation rate and greater stem cell factor secretion were observed than with SCs cultured without scaffold. ST 0.01% and TET 3% conditions offered the best compromise in terms of DNA elimination and extracellular matrix (ECM preservation, while ensuring good attachment, proliferation and functionality of human SCs. This study demonstrates the potential of using decellularized pig ITT for human testicular tissue engineering purposes.

PDMS-SiO{sub 2}-TiO{sub 2}-CaO hybrid materials – Cytocompatibility and nanoscale surface features

Energy Technology Data Exchange (ETDEWEB)

Almeida, J. Carlos [CICECO - Aveiro Institute of Materials, Department of Materials and Ceramic Engineering, University of Aveiro, 3810-193 Aveiro (Portugal); Wacha, András [Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar Tudósok körútja 2, Budapest 1117 (Hungary); Gomes, Pedro S.; Fernandes, M. Helena R. [Laboratory for Bone Metabolism and Regeneration, Faculdade de Medicina Dentária, Universidade do Porto (Portugal); Fernandes, M. Helena Vaz [CICECO - Aveiro Institute of Materials, Department of Materials and Ceramic Engineering, University of Aveiro, 3810-193 Aveiro (Portugal); Salvado, Isabel M. Miranda, E-mail: isabelmsalvado@ua.pt [CICECO - Aveiro Institute of Materials, Department of Materials and Ceramic Engineering, University of Aveiro, 3810-193 Aveiro (Portugal)

2016-07-01

Two PDMS-SiO{sub 2}-TiO{sub 2}-CaO porous hybrid materials were prepared using the same base composition, precursors, and solvents, but following two different sol-gel procedures, based on the authors' previous works where for the first time, in this hybrid system, calcium acetate was used as calcium source. The two different procedures resulted in monolithic materials with different structures, microstructures, and surface wettability. Even though both are highly hydrophobic (contact angles of 127.2° and 150.6°), and present different filling regimes due to different surface topographies, they have demonstrated to be cytocompatible when tested with human osteoblastic cells, against the accepted idea that high-hydrophobic surfaces are not suitable to cell adhesion and proliferation. At the nanoscale, the existence of hydrophilic silica domains containing calcium, where water molecules are physisorbed, is assumed to support this capability, as discussed. - Highlights: • Two hybrid materials were prepared following two different sol-gel procedures. • Both are highly hydrophobic but demonstrated to be cytocompatible. • Different filling regimes were observed.

Nanostructured calcium phosphate coatings on magnesium alloys: characterization and cytocompatibility with mesenchymal stem cells.

Science.gov (United States)

Iskandar, Maria Emil; Aslani, Arash; Tian, Qiaomu; Liu, Huinan

2015-05-01

This article reports the deposition and characterization of nanostructured calcium phosphate (nCaP) on magnesium-yttrium alloy substrates and their cytocompatibility with bone marrow derived mesenchymal stem cells (BMSCs). The nCaP coatings were deposited on magnesium and magnesium-yttrium alloy substrates using proprietary transonic particle acceleration process for the dual purposes of modulating substrate degradation and BMSC adhesion. Surface morphology and feature size were analyzed using scanning electron microscopy and quantitative image analysis tools. Surface elemental compositions and phases were analyzed using energy dispersive X-ray spectroscopy and X-ray diffraction, respectively. The deposited nCaP coatings showed a homogeneous particulate surface with the dominant feature size of 200-500 nm in the long axis and 100-300 nm in the short axis, and a Ca/P atomic ratio of 1.5-1.6. Hydroxyapatite was the major phase identified in the nCaP coatings. The modulatory effects of nCaP coatings on the sample degradation and BMSC behaviors were dependent on the substrate composition and surface conditions. The direct culture of BMSCs in vitro indicated that multiple factors, including surface composition and topography, and the degradation-induced changes in media composition, influenced cell adhesion directly on the sample surface, and indirect adhesion surrounding the sample in the same culture. The alkaline pH, the indicator of Mg degradation, played a role in BMSC adhesion and morphology, but not the sole factor. Additional studies are necessary to elucidate BMSC responses to each contributing factor.

The in vitro biomineralization and cytocompatibility of polydopamine coated carbon nanotubes

International Nuclear Information System (INIS)

Yan Penghua; Wang Jinqing; Wang Lin; Liu Bin; Lei Ziqiang; Yang Shengrong

2011-01-01

In this work, polydopamine coated carbon nanotubes were firstly prepared by a simple and feasible route. Then, for comparison, the in vitro bioactivity and cytocompatibility of the carbon nanotubes and the polydopamine coated carbon nanotubes were assessed by immersion study in simulated body fluids and 3-(4,5-dimethyldiazol-2-yl)-2,5-diphenyl tetrazolium bromide test using osteoblast cells (MC3T3-E1), respectively. As a result, it has been demonstrated that the introduction of polydopamine coating can greatly enhance the bioactivity and promote cell proliferation of the carbon nanotubes. The improvement of bioactive behavior is attributed to the good combination of catecholamines structure of the polydopamine and the structural advantages of carbon nanotubes as a framework material. It is anticipated that the polydopamine coated carbon nanotubes would find potential applications in bone tissue engineering and other biomedical areas.

The in vitro biomineralization and cytocompatibility of polydopamine coated carbon nanotubes

Energy Technology Data Exchange (ETDEWEB)

Yan Penghua [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, 18 Tianshui Middle Road, Lanzhou 730000 (China); Key Laboratory of Polymer Materials of Gansu Province, College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070 (China); Wang Jinqing, E-mail: jqwang@licp.cas.cn [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, 18 Tianshui Middle Road, Lanzhou 730000 (China); Wang Lin; Liu Bin [School of Stomatology, Lanzhou University, Lanzhou 730000 (China); Lei Ziqiang [Key Laboratory of Polymer Materials of Gansu Province, College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070 (China); Yang Shengrong, E-mail: sryang@lzb.ac.cn [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, 18 Tianshui Middle Road, Lanzhou 730000 (China); Key Laboratory of Polymer Materials of Gansu Province, College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070 (China)

2011-03-15

In this work, polydopamine coated carbon nanotubes were firstly prepared by a simple and feasible route. Then, for comparison, the in vitro bioactivity and cytocompatibility of the carbon nanotubes and the polydopamine coated carbon nanotubes were assessed by immersion study in simulated body fluids and 3-(4,5-dimethyldiazol-2-yl)-2,5-diphenyl tetrazolium bromide test using osteoblast cells (MC3T3-E1), respectively. As a result, it has been demonstrated that the introduction of polydopamine coating can greatly enhance the bioactivity and promote cell proliferation of the carbon nanotubes. The improvement of bioactive behavior is attributed to the good combination of catecholamines structure of the polydopamine and the structural advantages of carbon nanotubes as a framework material. It is anticipated that the polydopamine coated carbon nanotubes would find potential applications in bone tissue engineering and other biomedical areas.

Enhancement of Polymer Cytocompatibility by Nanostructuring of Polymer Surface

Czech Academy of Sciences Publication Activity Database

Slepička, P.; Kasálková-Slepičková, N.; Bačáková, Lucie; Kolská, Z.; Švorčík, V.

2012-01-01

Roč. 2012, č. 2012 (2012), ID527403 ISSN 1687-4110 R&D Projects: GA ČR(CZ) GBP108/12/G108 Institutional support: RVO:67985823 Keywords : polymer cytocompatibility * polymer surface * nanotechnology Subject RIV: EI - Biotechnology ; Bionics Impact factor: 1.547, year: 2012

Blood-Vessel Mimicking Structures by Stereolithographic Fabrication of Small Porous Tubes Using Cytocompatible Polyacrylate Elastomers, Biofunctionalization and Endothelialization

Directory of Open Access Journals (Sweden)

Birgit Huber

2016-04-01

Full Text Available Blood vessel reconstruction is still an elusive goal for the development of in vitro models as well as artificial vascular grafts. In this study, we used a novel photo-curable cytocompatible polyacrylate material (PA for freeform generation of synthetic vessels. We applied stereolithography for the fabrication of arbitrary 3D tubular structures with total dimensions in the centimeter range, 300 µm wall thickness, inner diameters of 1 to 2 mm and defined pores with a constant diameter of approximately 100 µm or 200 µm. We established a rinsing protocol to remove remaining cytotoxic substances from the photo-cured PA and applied thio-modified heparin and RGDC-peptides to functionalize the PA surface for enhanced endothelial cell adhesion. A rotating seeding procedure was introduced to ensure homogenous endothelial monolayer formation at the inner luminal tube wall. We showed that endothelial cells stayed viable and adherent and aligned along the medium flow under fluid-flow conditions comparable to native capillaries. The combined technology approach comprising of freeform additive manufacturing (AM, biomimetic design, cytocompatible materials which are applicable to AM, and biofunctionalization of AM constructs has been introduced as BioRap® technology by the authors.

Guanidine hydrochloride embedded polyurethanes as antimicrobial and absorptive wound dressing membranes with promising cytocompatibility

Energy Technology Data Exchange (ETDEWEB)

Sahraro, Maryam; Yeganeh, Hamid, E-mail: h.yeganeh@ippi.ac.ir; Sorayya, Marziyeh

2016-02-01

Preparation and assessments of novel absorptive wound dressing materials with efficient antimicrobial activity as well as very good cytocompatibility were described in this work. An amine terminated poly(hexamethylene guanidine hydrochloride) was prepared and used as curing agent of different epoxy-terminated polyurethane prepolymers. The structures of prepared materials were elucidated by evaluation of their {sup 1}H NMR and FTIR spectra. The recorded tensile strength of membranes confirmed the excellent dimensional stability of the film type dressings even at fully hydrated conditions. Therefore, these dressings could protect the wound bed from external forces during the healing period. The structurally optimized dressing membranes could preserve the desired moist environment over the wounded area, as a result of their balanced equilibrium, water absorption and water vapor transmission rate. Therefore, a very good condition for stimulation of self-healing of wound bed was attained. Also, owing to the presence of guanidine hydrochloride moieties embedded into the structure of dressings, efficient antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans were detected. In vitro cytotoxicity assay of the prepared dressings revealed cytocompatibility of these materials against fibroblast cells. Therefore, they could support cell growth and proliferation at the wounded area. - Highlights: • New polyurethane wound dressings with guanidine hydrochloride based antimicrobials • Maintaining moist and warm wound environment for accelerating healing • Proper tensile strength of dressings even at fully hydrated state • Excellent biocompatibility index due to proper selection of starting materials.

Cytocompatibility, cytotoxicity and genotoxicity analysis of dental implants

Science.gov (United States)

Reigosa, M.; Labarta, V.; Molinari, G.; Bernales, D.

2007-11-01

Several types of materials are frequently used for dental prostheses in dental medicine. Different treatments with titanium are the most used. The aim of the present study was to analyze by means of cytotoxicity and cytocompatibility techniques the capacity of dental implants to integrate to the bone tissue. Cultures of UMR 106 cell line derived from an osteosarcoma were used for bioassays mainly because they show many of the properties of osteoblasts. Dental implant samples provided by B&W company were compared with others of recognized trademarks. The first ones contain ASTM titanium (8348 GR2) with acid printing. Cytotoxicity was analyzed by means of lysosome activity, using the neutral red technique and alkaline phosphatase enzyme activity. Cell variability was determined by means of the acridine ethidium-orange bromide technique. One-way ANOVA and Bonferroni and Duncan post-ANOVA tests were used for the statistical analysis. The assays did not show significant differences among the dental implants analyzed. Our findings show that the dental prostheses studied present high biocompatibility, quantified by the bioassays performed. The techniques employed revealed that they can be a useful tool for the analysis of other materials for dental medicine use.

Cytocompatibility, cytotoxicity and genotoxicity analysis of dental implants

International Nuclear Information System (INIS)

M, Reigosa; V, Labarta; G, Molinari; D, Bernales

2007-01-01

Several types of materials are frequently used for dental prostheses in dental medicine. Different treatments with titanium are the most used. The aim of the present study was to analyze by means of cytotoxicity and cytocompatibility techniques the capacity of dental implants to integrate to the bone tissue. Cultures of UMR 106 cell line derived from an osteosarcoma were used for bioassays mainly because they show many of the properties of osteoblasts. Dental implant samples provided by B and W company were compared with others of recognized trademarks. The first ones contain ASTM titanium (8348 GR2) with acid printing. Cytotoxicity was analyzed by means of lysosome activity, using the neutral red technique and alkaline phosphatase enzyme activity. Cell variability was determined by means of the acridine ethidium-orange bromide technique. One-way ANOVA and Bonferroni and Duncan post-ANOVA tests were used for the statistical analysis. The assays did not show significant differences among the dental implants analyzed. Our findings show that the dental prostheses studied present high biocompatibility, quantified by the bioassays performed. The techniques employed revealed that they can be a useful tool for the analysis of other materials for dental medicine use

Effects of DCPD cement chemistry on degradation properties and cytocompatibility: comparison of MCPM/β-TCP and MCPM/HA formulations

International Nuclear Information System (INIS)

Alge, Daniel L; Goebel, W Scott; Chu, Tien-Min Gabriel

2013-01-01

Dicalcium phosphate dihydrate (DCPD) cements are attractive biomaterials for bone repair, and a number of different DCPD cement formulations have been proposed in the literature. In this study, we have specifically compared monocalcium phosphate monohydrate (MCPM)/hydroxyapatite (HA) and MCPM/β-tricalcium phosphate (β-TCP) formulations to test the hypothesis that DCPD cement chemistry affects the degradation properties and cytocompatibility of the cement. Using simple in vitro models we found that MCPM/β-TCP formulations degraded primarily by DCPD dissolution, which was associated with a slight pH drop and relatively low mass loss. Cytocompatibility testing of cement conditioned culture media revealed no significant change in cell viability relative to the negative control for all of the MCPM/β-TCP formulations. In contrast, the MCPM/HA formulations were prone to undergo rapid conversion of DCPD to HA, resulting in a sharp pH drop and extensive mass loss. A stoichiometric excess of HA in the cement was found to accelerate the conversion process, and significant cytotoxicity was observed for the MCPM/HA formulations containing excess HA. Collectively, these results show that, although the product of the setting reaction is the same, DCPD cements produced with MCPM/HA and MCPM/β-TCP formulations differ significantly in their degradation properties and cytocompatibility. These differences may have important implications for the selection of a DCPD cement formulation for clinical application. (paper)

Hydroxyapatite coatings with oriented nanoplate and nanorod arrays: Fabrication, morphology, cytocompatibility and osteogenic differentiation

Energy Technology Data Exchange (ETDEWEB)

Chen, Wei [The Education Ministry Key Lab of Resource Chemistry and Shanghai Key Laboratory of Rare Earth Functional Materials, Shanghai Normal University, Shanghai 200234 (China); Tian, Bo [Shanghai Key Laboratory of Orthopedic Implant, Department of Orthopedic Surgery, Shanghai Ninth People' s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011 (China); Lei, Yong; Ke, Qin-Fei [The Education Ministry Key Lab of Resource Chemistry and Shanghai Key Laboratory of Rare Earth Functional Materials, Shanghai Normal University, Shanghai 200234 (China); Zhu, Zhen-An, E-mail: zhuzhenan2006@126.com [Shanghai Key Laboratory of Orthopedic Implant, Department of Orthopedic Surgery, Shanghai Ninth People' s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011 (China); Guo, Ya-Ping, E-mail: ypguo@shnu.edu.cn [The Education Ministry Key Lab of Resource Chemistry and Shanghai Key Laboratory of Rare Earth Functional Materials, Shanghai Normal University, Shanghai 200234 (China)

2016-10-01

Hydroxyapatite (HA) crystals exhibit rod-like shape with c-axis orientation and plate-like shape with a(b)-axis orientation in vertebrate bones and tooth enamel surfaces, respectively. Herein, we report the synthesis of HA coatings with the oriented nanorod arrays (RHACs) and HA coatings with oriented nanoplate arrays (PHACs) by using bioglass coatings as sacrificial templates. After soaking in simulated body fluid (SBF) at 120 °C, the bioglass coatings are hydrothermally converted into the HA coatings via a dissolution-precipitation reaction. If the Ca/P ratios in SBF are 2.50 and 1.25, the HA crystals on the coatings are oriented nanorod arrays and oriented nanoplate arrays, respectively. Moreover, the bioglass coatings are treated with SBF at 37 °C, plate-like HA coatings with a low crystallinity (SHACs) are prepared. As compared with the Ti6Al4V and SHACs, the human bone marrow stromal cells (hBMSCs) on the RHACs and PHACs have better cell adhesion, spreading, proliferation and osteogenic differentiation because of their moderately hydrophilic surfaces and similar chemical composition, morphology and crystal orientation to human hard tissues. Notably, the morphologies of HA crystals have no obvious effects on cytocompatibility and osteogenic differentiation. Hence, the HA coatings with oriented nanoplate arrays or oriented nanorod arrays have a great potential for orthopedic applications. - Highlights: • We prepare hydroxyapatite coatings with oriented nanoplate and nanorod arrays. • Hydroxyapatite coatings are in situ converted from bioglass coatings. • Hydroxyapatite coatings have good cytocompatibility and osteogenic differentiation. • Oriented hydroxyapatite coatings are used for orthopedic implants.

Hydroxyapatite coatings with oriented nanoplate and nanorod arrays: Fabrication, morphology, cytocompatibility and osteogenic differentiation

International Nuclear Information System (INIS)

Chen, Wei; Tian, Bo; Lei, Yong; Ke, Qin-Fei; Zhu, Zhen-An; Guo, Ya-Ping

2016-01-01

Hydroxyapatite (HA) crystals exhibit rod-like shape with c-axis orientation and plate-like shape with a(b)-axis orientation in vertebrate bones and tooth enamel surfaces, respectively. Herein, we report the synthesis of HA coatings with the oriented nanorod arrays (RHACs) and HA coatings with oriented nanoplate arrays (PHACs) by using bioglass coatings as sacrificial templates. After soaking in simulated body fluid (SBF) at 120 °C, the bioglass coatings are hydrothermally converted into the HA coatings via a dissolution-precipitation reaction. If the Ca/P ratios in SBF are 2.50 and 1.25, the HA crystals on the coatings are oriented nanorod arrays and oriented nanoplate arrays, respectively. Moreover, the bioglass coatings are treated with SBF at 37 °C, plate-like HA coatings with a low crystallinity (SHACs) are prepared. As compared with the Ti6Al4V and SHACs, the human bone marrow stromal cells (hBMSCs) on the RHACs and PHACs have better cell adhesion, spreading, proliferation and osteogenic differentiation because of their moderately hydrophilic surfaces and similar chemical composition, morphology and crystal orientation to human hard tissues. Notably, the morphologies of HA crystals have no obvious effects on cytocompatibility and osteogenic differentiation. Hence, the HA coatings with oriented nanoplate arrays or oriented nanorod arrays have a great potential for orthopedic applications. - Highlights: • We prepare hydroxyapatite coatings with oriented nanoplate and nanorod arrays. • Hydroxyapatite coatings are in situ converted from bioglass coatings. • Hydroxyapatite coatings have good cytocompatibility and osteogenic differentiation. • Oriented hydroxyapatite coatings are used for orthopedic implants.

Sea water take-up facility for cooling reactor auxiliary

International Nuclear Information System (INIS)

Numata, Noriko; Mizutani, Akira; Hirako, Shizuka; Uchiyama, Yuichi; Oda, Atsushi.

1997-01-01

The present invention provides an improvement of a cooling sea water take-up facility for cooling auxiliary equipments of nuclear power plant. Namely, an existent sea water take-up facility for cooling reactor auxiliary equipments has at least two circulation water systems and three independent sea water systems for cooling reactor auxiliary equipments. In this case, a communication water channel is disposed, which connects the three independent sea water systems for cooling reactor auxiliary equipments mutually by an opening/closing operation of a flow channel partitioning device. With such a constitution, even when any combination of two systems among the three circulation water systems is in inspection at the same time, one system for cooling the reactor auxiliary equipments can be kept operated, and one system is kept in a stand-by state by the communication water channel upon periodical inspection of water take-up facility for cooling the auxiliary equipments. As a result, the sea water take-up facility for cooling auxiliary equipments of the present invention have operation efficiency higher than that of a conventional case while keeping the function and safety at the same level as in the conventional case. (I.S.)

Take-up device for incore instruments for nuclear power plant

International Nuclear Information System (INIS)

Watanabe, Shigeru.

1978-01-01

Purpose: To obtain a take-up device being capable of loading through the control rod inlet and operating with ease on a control rod exchange platform by detacheably mounting a reel-containing cask to a truck carrying a spool driving motor. Constitution: A take-up device is located while running a truck along guide rails from control rod inlet. A cask door is opened on a control rod exchange platform and a compression coupling tube is connected to the lower end of an instrument. Thereafter, a spool is rotated by a driving motor and a detection tube is taken up and wound into a spool through a take-up port. (Yoshino, Y.)

High strength, biodegradable and cytocompatible alpha tricalcium phosphate-iron composites for temporal reduction of bone fractures.

Science.gov (United States)

Montufar, E B; Casas-Luna, M; Horynová, M; Tkachenko, S; Fohlerová, Z; Diaz-de-la-Torre, S; Dvořák, K; Čelko, L; Kaiser, J

2018-04-01

In this work alpha tricalcium phosphate (α-TCP)/iron (Fe) composites were developed as a new family of biodegradable, load-bearing and cytocompatible materials. The composites with composition from pure ceramic to pure metallic samples were consolidated by pulsed electric current assisted sintering to minimise processing time and temperature while improving their mechanical performance. The mechanical strength of the composites was increased and controlled with the Fe content, passing from brittle to ductile failure. In particular, the addition of 25 vol% of Fe produced a ceramic matrix composite with elastic modulus much closer to cortical bone than that of titanium or biodegradable magnesium alloys and specific compressive strength above that of stainless steel, chromium-cobalt alloys and pure titanium, currently used in clinic for internal fracture fixation. All the composites studied exhibited higher degradation rate than their individual components, presenting values around 200 μm/year, but also their compressive strength did not show a significant reduction in the period required for bone fracture consolidation. Composites showed preferential degradation of α-TCP areas rather than β-TCP areas, suggesting that α-TCP can produce composites with higher degradation rate. The composites were cytocompatible both in indirect and direct contact with bone cells. Osteoblast-like cells attached and spread on the surface of the composites, presenting proliferation rate similar to cells on tissue culture-grade polystyrene and they showed alkaline phosphatase activity. Therefore, this new family of composites is a potential alternative to produce implants for temporal reduction of bone fractures. Biodegradable alpha-tricalcium phosphate/iron (α-TCP/Fe) composites are promising candidates for the fabrication of temporal osteosynthesis devices. Similar to biodegradable metals, these composites can avoid implant removal after bone fracture healing, particularly in

Health insurance take-up by the near-elderly.

Science.gov (United States)

Buchmueller, Thomas C; Ohri, Sabina

2006-12-01

To examine the effect of price on the demand for health insurance by early retirees between the ages of 55 and 64. Administrative health plan enrollment data from a medium-sized U.S. employer. The analysis takes advantage of a natural experiment created by the firm's health insurance contribution policy. The amount the firm contributes toward retiree health insurance coverage depends on when a person retired and her years of service at that date. As a result of this policy, there is considerable variation in out-of-pocket premiums faced by individuals in the data. This variation is independent of the nonprice attributes of the health insurance plans offered and is plausibly exogenous to individual characteristics that are likely to affect the demand for insurance. A probit model is used to estimate the decision to take-up employer-sponsored health insurance by early retirees between the ages of 55 and 64. Demand for insurance is measured as a function of out-of-pocket premiums and a set of individual characteristics. We find that price has a small but statistically significant effect on the decision to take up coverage. Estimated price elasticities range from -0.10 to -0.16, depending on the sample. The implied elasticities are comparable with results found in previous studies using very different data. Our estimates indicate that policy proposals for a Medicare buy-in or a nongroup tax credit will have a modest impact on take-up rates of near-elderly retirees.

Ginkgo biloba: a natural reducing agent for the synthesis of cytocompatible graphene

Directory of Open Access Journals (Sweden)

Gurunathan S

2014-01-01

Full Text Available Sangiliyandi Gurunathan, Jae Woong Han, Jung Hyun Park, Vasuki Eppakayala, Jin-Hoi Kim Department of Animal Biotechnology, Konkuk University, Seoul, South Korea Background: Graphene is a novel two-dimensional planar nanocomposite material consisting of rings of carbon atoms with a hexagonal lattice structure. Graphene exhibits unique physical, chemical, mechanical, electrical, elasticity, and cytocompatible properties that lead to many potential biomedical applications. Nevertheless, the water-insoluble property of graphene restricts its application in various aspects of biomedical fields. Therefore, the objective of this work was to find a novel biological approach for an efficient method to synthesize water-soluble and cytocompatible graphene using Ginkgo biloba extract (GbE as a reducing and stabilizing agent. In addition, we investigated the biocompatibility effects of graphene in MDA-MB-231 human breast cancer cells. Materials and methods: Synthesized graphene oxide (GO and GbE-reduced GO (Gb-rGO were characterized using various sequences of techniques: ultraviolet-visible (UV-vis spectroscopy, Fourier-transform infrared spectroscopy (FTIR, dynamic light scattering (DLS, scanning electron microscopy (SEM, atomic force microscopy (AFM, and Raman spectroscopy. Biocompatibility of GO and Gb-rGO was assessed in human breast cancer cells using a series of assays, including cell viability, apoptosis, and alkaline phosphatase (ALP activity. Results: The successful synthesis of graphene was confirmed by UV-vis spectroscopy and FTIR. DLS analysis was performed to determine the average size of GO and Gb-rGO. X-ray diffraction studies confirmed the crystalline nature of graphene. SEM was used to investigate the surface morphologies of GO and Gb-rGO. AFM was employed to investigate the morphologies of prepared graphene and the height profile of GO and Gb-rGO. The formation of defects in Gb-rGO was confirmed by Raman spectroscopy. The biocompatibility

In vitro corrosion properties and cytocompatibility of Fe-Ga alloys as potential biodegradable metallic materials

Energy Technology Data Exchange (ETDEWEB)

Wang, Henan; Zheng, Yang; Liu, Jinghua; Jiang, Chengbao; Li, Yan, E-mail: liyan@buaa.edu.cn

2017-02-01

The in vitro biodegradable properties and cytocompatibility of Fe-Ga alloys including Fe{sub 81}Ga{sub 19}, (Fe{sub 81}Ga{sub 19}){sub 98}B{sub 2} and (Fe{sub 81}Ga{sub 19}){sub 99.5}(TaC){sub 0.5}, and pure Fe were investigated for biomedical applications. The microstructure of the alloys was characterized using X-ray diffraction spectroscopy and optical microscopy. The results showed that A2 and D0{sub 3} phases were detected for the three types of Fe-Ga alloys, and additional Fe{sub 2}B and TaC phases were found in the (Fe{sub 81}Ga{sub 19}){sub 98}B{sub 2} and (Fe{sub 81}Ga{sub 19}){sub 99.5}(TaC){sub 0.5} alloys, respectively. The corrosion rates of the Fe-Ga alloys were higher than that of pure Fe, as demonstrated by both potentiodynamic polarization measurements and immersion tests in simulated body fluid. The alloying element Ga lowered the corrosion potential of the Fe matrix and made it more susceptible to corrosion. Severe pitting corrosion developed on the surface of the Fe{sub 81}Ga{sub 19} alloy after the addition of ternary B or TaC due to the multi-phase microstructures. The MC3T3-E1 cells exhibited good adhesion and proliferation behavior on the surfaces of the Fe-Ga alloys after culture for 4 h and 24 h. - Highlights: • Fe-Ga alloys showed a higher degradation rate than pure Fe. • Fe-Ga alloys exhibited good cytocompatibility for the MC3T3-E1 cells. • The MC3T3-E1 cells were tolerable to the corrosion products of Fe-Ga alloys.

Reasons encouraging adolescents to take up smoking

NARCIS (Netherlands)

Orosova, Olga; Geckova, Andrea Madarasova; Bacikova-Sleskova, Maria; van Dijk, Jitse P.

2008-01-01

Aim: To understand adolescents' smoking behavior by analyzing retrospective self-ratings of the reasons encouraging them to take up smoking. Method: Participating in the study were 883 students (373 boys) of elementary and secondary schools in Kosice, Slovak Republic (74.9% of adolescents in the

Antibacterial properties and cytocompatibility of tantalum oxide coatings with different silver content

International Nuclear Information System (INIS)

Huang, Heng-Li; Chang, Yin-Yu; Chen, Hung-Jui; Chou, Yu-Kai; Lai, Chih-Ho; Chen, Michael Y. C.

2014-01-01

Tantalum (Ta) oxides and their coatings have been proved to increase their applications in the biomedical fields by improving osseointegration and wear resistance. In this study, Ta oxide coatings containing different proportions of Ag are deposited on SS304 materials. A twin-gun magnetron sputtering system is used to deposit the tantalum oxide-Ag coating. In this study, Staphylococcus aureus, which exhibits physiological commensalism on the human skin, nares, and mucosal and oral areas, is chosen as the model for in vitro antibacterial analyses via a fluorescence staining method using Syto9. The cytocompatibility and adhesive morphology of human skin fibroblast cells (CCD-966SK) on the coatings are also determined by using the microculture tetrazolium assay. This study shows that Ta 2 O 5 and Ta 2 O 5 -Ag coatings with 12.5 at. % of Ag exhibit improved antibacterial effects against S. aureus and have good skin fibroblast cell cellular biocompatibility

Antibacterial properties and cytocompatibility of tantalum oxide coatings with different silver content

Energy Technology Data Exchange (ETDEWEB)

Huang, Heng-Li [School of Dentistry, China Medical University, Taichung 404, Taiwan (China); Chang, Yin-Yu, E-mail: yinyu@mail2000.com.tw; Chen, Hung-Jui; Chou, Yu-Kai [Department of Mechanical and Computer-Aided Engineering, National Formosa University, Yunlin 632, Taiwan (China); Lai, Chih-Ho [School of Medicine, China Medical University, Taichung 404, Taiwan (China); Chen, Michael Y. C. [Division of Oral and Maxillofacial Surgery, China Medical University Hospital, Taichung 404, Taiwan (China)

2014-03-15

Tantalum (Ta) oxides and their coatings have been proved to increase their applications in the biomedical fields by improving osseointegration and wear resistance. In this study, Ta oxide coatings containing different proportions of Ag are deposited on SS304 materials. A twin-gun magnetron sputtering system is used to deposit the tantalum oxide-Ag coating. In this study, Staphylococcus aureus, which exhibits physiological commensalism on the human skin, nares, and mucosal and oral areas, is chosen as the model for in vitro antibacterial analyses via a fluorescence staining method using Syto9. The cytocompatibility and adhesive morphology of human skin fibroblast cells (CCD-966SK) on the coatings are also determined by using the microculture tetrazolium assay. This study shows that Ta{sub 2}O{sub 5} and Ta{sub 2}O{sub 5}-Ag coatings with 12.5 at. % of Ag exhibit improved antibacterial effects against S. aureus and have good skin fibroblast cell cellular biocompatibility.

Incorporation of zinc oxide nanoparticles into chitosan-collagen 3D porous scaffolds: Effect on morphology, mechanical properties and cytocompatibility of 3D porous scaffolds.

Science.gov (United States)

Ullah, Saleem; Zainol, Ismail; Idrus, Ruszymah Hj

2017-11-01

The zinc oxide nanoparticles (particles size chitosan-collagen 3D porous scaffolds and investigated the effect of zinc oxide nanoparticles incorporation on microstructure, mechanical properties, biodegradation and cytocompatibility of 3D porous scaffolds. The 0.5%, 1.0%, 2.0% and 4.0% zinc oxide nanoparticles chitosan-collagen 3D porous scaffolds were fabricated via freeze-drying technique. The zinc oxide nanoparticles incorporation effects consisting in chitosan-collagen 3D porous scaffolds were investigated by mechanical and swelling tests, and effect on the morphology of scaffolds examined microscopically. The biodegradation and cytocompatibility tests were used to investigate the effects of zinc oxide nanoparticles incorporation on the ability of scaffolds to use for tissue engineering application. The mean pore size and swelling ratio of scaffolds were decreased upon incorporation of zinc oxide nanoparticles however, the porosity, tensile modulus and biodegradation rate were increased upon incorporation of zinc oxide nanoparticles. In vitro culture of human fibroblasts and keratinocytes showed that the zinc oxide nanoparticles facilitated cell adhesion, proliferation and infiltration of chitosan-collagen 3D porous scaffolds. It was found that the zinc oxide nanoparticles incorporation enhanced porosity, tensile modulus and cytocompatibility of chitosan-collagen 3D porous scaffolds. Copyright © 2017 Elsevier B.V. All rights reserved.

Nanoscale size effect in in situ titanium based composites with cell viability and cytocompatibility studies

Energy Technology Data Exchange (ETDEWEB)

Miklaszewski, Andrzej, E-mail: andrzej.miklaszewski@put.poznan.pl [Institute of Materials Science and Engineering, Poznan University of Technology, Jana Pawla II 24, 61-138 Poznan (Poland); Jurczyk, Mieczysława U. [Division Mother' s and Child' s Health, Poznan University of Medical Sciences, Polna 33, 60-535 Poznan (Poland); Kaczmarek, Mariusz [Department of Immunology, Chair of Clinical Immunology, Poznan University of Medical Sciences, Rokietnicka 5D, 60-806 Poznan (Poland); Paszel-Jaworska, Anna; Romaniuk, Aleksandra; Lipińska, Natalia [Department of Clinical Chemistry and Molecular Diagnostics, Poznan University of Medical Sciences, Przybyszewskiego 49, 60-355 Poznan (Poland); Żurawski, Jakub [Department of Immunobiochemistry, Chair of Biology and Environmental Sciences, Poznan University of Medical Sciences, Rokietnicka 8, 60-806 Poznan (Poland); Urbaniak, Paulina [Department of Cell Biology, Poznan University of Medical Sciences, Rokietnicka 5D, 60-806 Poznan (Poland); Jurczyk, Mieczyslaw [Institute of Materials Science and Engineering, Poznan University of Technology, Jana Pawla II 24, 61-138 Poznan (Poland)

2017-04-01

Novel in situ Metal Matrix Nanocomposite (MMNC) materials based on titanium and boron, revealed their new properties in the nanoscale range. In situ nanocomposites, obtained through mechanical alloying and traditional powder metallurgy compaction and sintering, show obvious differences to their microstructural analogue. A unique microstructure connected with good mechanical properties reliant on the processing conditions favour the nanoscale range of results of the Ti-TiB in situ MMNC example. The data summarised in this work, support and extend the knowledge boundaries of the nanoscale size effect that influence not only the mechanical properties but also the studies on the cell viability and cytocompatibility. Prepared in the same bulk, in situ MMNC, based on titanium and boron, could be considered as a possible candidate for dental implants and other medical applications. The observed relations and research conclusions are transferable to the in situ MMNC material group. Aside from all the discussed relations, the increasing share of these composites in the ever-growing material markets, heavily depends on the attractiveness and a possible wider application of these composites as well as their operational simplicity presented in this work. - Highlights: • Nano and microscale size precursor influence the final composite microstructure and properties. • Obtained from the nanoscale precursor sinters, characterise with a uniform and highly dispersed microstructure • Mechanical properties favoured Nano scale size precursor • Boron addition could be significantly reduced for moderate properties range. • A possible candidate for dental implants and other medical applications.

A study of degradation resistance and cytocompatibility of super-hydrophobic coating on magnesium.

Science.gov (United States)

Zhang, Yufen; Feyerabend, Frank; Tang, Shawei; Hu, Jin; Lu, Xiaopeng; Blawert, Carsten; Lin, Tiegui

2017-09-01

Calcium stearate based super-hydrophobic coating was deposited on plasma electrolytic oxidation (PEO) pre-treated magnesium substrate. The pre-treated magnesium and super-hydrophobic coating covered sample were characterized by scanning electron microscopy, X-ray diffraction and electrochemical corrosion measurements. The cytocompatibility and degradation resistance of magnesium, pre-treated magnesium and super-hydrophobic coating were analysed in terms of cell adhesion and osteoblast differentiation. The results indicate that the calcium stearate top coating shows super-hydrophobicity and that the surface is composed of micro/nanostructure. The super-hydrophobic coating covered sample shows higher barrier properties compared with the PEO pre-treated magnesium and bare magnesium. Human osteoblast proliferation, but not differentiation is enhanced by the PEO coating. Contrary, the super-hydrophobic coating reduces proliferation, but enhances differentiation of osteoblast, observable by the formation of hydroxyapatite. The combination of corrosion protection and cell reaction indicates that this system could be interesting for biomedical applications. Copyright © 2017 Elsevier B.V. All rights reserved.

Vibration analysis on automatic take-up device of belt conveyor

Science.gov (United States)

Qin, Tailong; Wei, Jin

2008-10-01

Through introducing application condition of belt conveyor in the modern mining industry, the paper proposed, in the dynamic course of its starting, braking or loading, it would produce moving tension and elastic wave. And analyzed the factors cause the automatic take-up device of belt conveyor vibrating: the take-up device's structure and the elastic wave. Finally the paper proposed the measure to reduce vibration and carried on the modeling and simulation on the tension buffer device.

Cytocompatible cellulose hydrogels containing trace lignin

International Nuclear Information System (INIS)

Nakasone, Kazuki; Kobayashi, Takaomi

2016-01-01

Sugarcane bagasse was used as a cellulose resource to prepare transparent and flexible cellulose hydrogel films. On the purification process from bagasse to cellulose, the effect of lignin residues in the cellulose was examined for the properties and cytocompatibility of the resultant hydrogel films. The cellulose was dissolved in lithium chloride/N,N-dimethylacetamide solution and converted to hydrogel films by phase inversion. In the purification process, sodium hydroxide (NaOH) treatment time was changed from 1 to 12 h. This resulted in cellulose hydrogel films having small amounts of lignin from 1.62 to 0.68%. The remaining lignin greatly affected hydrogel properties. Water content of the hydrogel films was increased from 1153 to 1525% with a decrease of lignin content. Moreover, lower lignin content caused weakening of tensile strength from 0.80 to 0.43 N/mm"2 and elongation from 45.2 to 26.5%. Also, similar tendency was observed in viscoelastic behavior of the cellulose hydrogel films. Evidence was shown that the lignin residue was effective for the high strength of the hydrogel films. In addition, scanning probe microscopy in the morphological observation was suggested that the trace lignin in the cellulose hydrogel affected the cellulose fiber aggregation in the hydrogel network. The trace of lignin in the hydrogels also influenced fibroblast cell culture on the hydrogel films. The hydrogel film containing 1.68% lignin showed better fibroblast compatibility as compared to cell culture polystyrene dish used as reference. - Highlights: • Cellulose hydrogel films with trace lignin were obtained from sugarcane bagasse. • Lignin content was found to be in the range of 1.62 − 0.68% by UV–Vis spectroscopy. • Higher lignin content strengthened mechanical properties of the hydrogel films. • Trace lignin affected the hydrogel morphology such as roughness and porosity. • High cell proliferation was observed in the hydrogel containing 1.68% lignin.

Cytocompatible cellulose hydrogels containing trace lignin

Energy Technology Data Exchange (ETDEWEB)

Nakasone, Kazuki; Kobayashi, Takaomi, E-mail: takaomi@nagaoakut.ac.jp

2016-07-01

Sugarcane bagasse was used as a cellulose resource to prepare transparent and flexible cellulose hydrogel films. On the purification process from bagasse to cellulose, the effect of lignin residues in the cellulose was examined for the properties and cytocompatibility of the resultant hydrogel films. The cellulose was dissolved in lithium chloride/N,N-dimethylacetamide solution and converted to hydrogel films by phase inversion. In the purification process, sodium hydroxide (NaOH) treatment time was changed from 1 to 12 h. This resulted in cellulose hydrogel films having small amounts of lignin from 1.62 to 0.68%. The remaining lignin greatly affected hydrogel properties. Water content of the hydrogel films was increased from 1153 to 1525% with a decrease of lignin content. Moreover, lower lignin content caused weakening of tensile strength from 0.80 to 0.43 N/mm{sup 2} and elongation from 45.2 to 26.5%. Also, similar tendency was observed in viscoelastic behavior of the cellulose hydrogel films. Evidence was shown that the lignin residue was effective for the high strength of the hydrogel films. In addition, scanning probe microscopy in the morphological observation was suggested that the trace lignin in the cellulose hydrogel affected the cellulose fiber aggregation in the hydrogel network. The trace of lignin in the hydrogels also influenced fibroblast cell culture on the hydrogel films. The hydrogel film containing 1.68% lignin showed better fibroblast compatibility as compared to cell culture polystyrene dish used as reference. - Highlights: • Cellulose hydrogel films with trace lignin were obtained from sugarcane bagasse. • Lignin content was found to be in the range of 1.62 − 0.68% by UV–Vis spectroscopy. • Higher lignin content strengthened mechanical properties of the hydrogel films. • Trace lignin affected the hydrogel morphology such as roughness and porosity. • High cell proliferation was observed in the hydrogel containing 1.68% lignin.

Device to take up slack in monorail cables

Energy Technology Data Exchange (ETDEWEB)

Szymanski, J

1978-08-01

This paper discusses the necessity to take up the slack of a monorail cable in an HBNPC mine in order to ensure good adhesion between the metal cable and the pulley. A new device has been tested with satisfactory results.

In vitro cytocompatibility evaluation of chitosan/graphene oxide 3D scaffold composites designed for bone tissue engineering.

Science.gov (United States)

Dinescu, Sorina; Ionita, Mariana; Pandele, Andreea Madalina; Galateanu, Bianca; Iovu, Horia; Ardelean, Aurel; Costache, Marieta; Hermenean, Anca

2014-01-01

Extensively studied nowadays, graphene oxide (GO) has a benefic effect on cell proliferation and differentiation, thus holding promise for bone tissue engineering (BTE) approaches. The aim of this study was not only to design a chitosan 3D scaffold improved with GO for optimal BTE, but also to analyze its physicochemical properties and to evaluate its cytocompatibility and ability to support cell metabolic activity and proliferation. Overall results show that the addition of GO in the scaffold's composition improved mechanical properties and pore formation and enhanced the bioactivity of the scaffold material for tissue engineering. The new developed CHT/GO 3 wt% scaffold could be a potential candidate for further in vitro and in vivo osteogenesis studies and BTE approaches.

Fabrication of thermoplastic ductile films of chitin butyrate/poly(ɛ-caprolactone) blends and their cytocompatibility.

Science.gov (United States)

Hashiwaki, Hiroki; Teramoto, Yoshikuni; Nishio, Yoshiyuki

2014-12-19

We fabricate thermoplastic films of chitin burtyrate (ChB)/poly(ɛ-caprolactone) (PCL) blends with different degree of miscibility (miscible (M), partially miscible (PM), and immiscible (IM)), and examined the feasibility as a cell scaffold system through evaluating mechanical properties and cytocompatibility. We found a remediation of the brittleness and an increase in ductility of ChB by blending PCL for the M and PM blends. The blend films were subjected to alkaline hydrolysis (2-M NaOH/37°C/48 h) with expectation of the improvement of the surface hydrophilicity and cell accessibility. ATR-FTIR spectroscopy of the alkaline-treated PM and IM films revealed that PCL component and ester side-chains of acyl chitin were selectively removed from the surface domain. L929 fibroblast cells well adhered and proliferated on these films. Therefore, the materials possess a great potential for the utilization as a thermoplastic cell scaffold in tissue engineering by adequate selection of the degree of miscibility and post treatment. Copyright © 2014 Elsevier Ltd. All rights reserved.

Cytocompatibility of chitosan and collagen-chitosan scaffolds for tissue engineering

Directory of Open Access Journals (Sweden)

Ligia L. Fernandes

2011-01-01

Full Text Available In this work, chitosan and collagen-chitosan porous scaffolds were produced by the freeze drying method and characterized as potential skin substitutes. Their beneficial effects on soft tissues justify the choice of both collagen and chitosan. Samples were characterized using scanning electron microscope, Fourier Transform InfraRed Spectroscopy (FTIR and thermogravimetry (TG. The in vitro cytocompatibility of chitosan and collagen-chitosan scaffolds was evaluated with three different assays. Phenol and titanium powder were used as positive and negative controls, respectively. Scanning electron microscopy revealed the highly interconnected porous structure of the scaffolds. The addition of collagen to chitosan increased both pore diameter and porosity of the scaffolds. Results of FTIR and TG analysis indicate that the two polymers interact yielding a miscible blend with intermediate thermal degradation properties. The reduction of XTT ((2,3-bis[2-methyloxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide and the uptake of Neutral Red (NR were not affected by the blend or by the chitosan scaffold extracts, but the blend and the titanium powder presented greater incorporation of Crystal Violet (CV than phenol and chitosan alone. In conclusion, collagen-chitosan scaffolds produced by freeze-drying methods were cytocompatible and presented mixed properties of each component with intermediate thermal degradation properties.

Electrospun Zein/Gelatin Scaffold-Enhanced Cell Attachment and Growth of Human Periodontal Ligament Stem Cells

Directory of Open Access Journals (Sweden)

Fanqiao Yang

2017-10-01

Full Text Available Periodontitis is a widespread dental disease affecting 10 to 15% of worldwide adult population, yet the current treatments are far from satisfactory. The human periodontal ligament stem cell is a promising potential seed cell population type in cell-based therapy and tissue regeneration, which require appropriate scaffold to provide a mimic extracellular matrix. Zein, a native protein derived from corn, has an excellent biodegradability, and therefore becomes a hotspot on research and application in the field of biomaterials. However, the high hydrophobicity of zein is unfavorable for cell adhesion and thus greatly limits its use. In this study, we fabricate co-electrospun zein/gelatin fiber scaffolds in order to take full advantages of the two natural materials and electrospun fiber structure. Zein and gelatin in four groups of different mass ratios (100:00, 100:20, 100:34, 100:50, and dissolved the mixtures in 1,1,1,3,3,3-hexafluoro-2-propanol, then produced membranes by electrospinning. The results showed that the scaffolds were smooth and homogeneous, as shown in scanning electron micrographs. The diameter of hybrid fibers was increased from 69 ± 22 nm to 950 ± 356 nm, with the proportion of gelatin increase. The cell affinity of zein/gelatin nanofibers was evaluated by using human periodontal ligament stem cells. The data showed that hydrophilicity and cytocompatibility of zein nanofibers were improved by blended gelatin. Taken together, our results indicated that the zein/gelatin co-electrospun fibers had sufficient mechanical properties, satisfied cytocompatibility, and can be utilized as biological scaffolds in the field of tissue regeneration.

UPS Project for GSM base stations with a fuel cell (PEM fuel cell back-up system) - Final report; Projekt USV fuer GSM-Basisstationen mit BZ (PEM fuel cell back-up system) - Abschlussbericht

Energy Technology Data Exchange (ETDEWEB)

Trachte, U.

2007-07-01

The University of applied sciences HTA Lucerne designed a prototype of an uninterruptible power supply (UPS) with Fuel Cell technology instead of lead-acid batteries and put it into operation. The delayed start-up of the Fuel Cell was bridged with ultra capacitor technology. In a first project stage the system was designed, assembled and tested in laboratory. In a second stage the installation was connected to a real base station of a telecommunication antenna and put to field tests for one year. The field test included monthly simulations of power failure with antenna load of about 2.4 kW as well as tests with external load up to 8.5 kW to establish the characteristic diagram. Hydrogen was provided by two 50 l pressure tanks. The full quantity of hydrogen secured a stand-alone operation of the Fuel Cell system for about 6 hours under antenna load. The results of the 101 grid-failure simulations demonstrate a very reliable start-up behaviour of the Fuel Cell System. Also during a real power failure due to a thunderstorm the installation provided the demanded power without any problem. The total duration of operation of the Fuel Cell during the field tests was 39 hours. No degradation could be noticed. The project takes place in collaboration with the industrial partners APC Industrial Systems, as a producer and market leader of UPS-Systems, and Swisscom Mobile AG, as a user of UPS-systems in telecommunications. Following the good results and in order to get more experience in long-term operation of the Fuel Cell system the tests will go on for two more years. (author)

Modulation, functionality, and cytocompatibility of three-dimensional printing materials made from chitosan-based polysaccharide composites.

Science.gov (United States)

Wu, Chin-San

2016-12-01

The mechanical properties, cytocompatibility, and fabrication of three-dimensional (3D) printing strips of composite materials containing polylactide (PLA) and chitosan (CS) were evaluated. Maleic anhydride-grafted polylactide (PLA-g-MA) and CS were used to enhance the desired characteristics of these composites. The PLA-g-MA/CS materials exhibited better mechanical properties than the PLA/CS composites; this effect was attributed to a greater compatibility between the grafted polyester and CS. The water resistance of the PLA-g-MA/CS composites was greater than that of the PLA/CS composites; cytocompatibility evaluation with human foreskin fibroblasts (FBs) indicated that both materials were nontoxic. Moreover, CS enhanced the antibacterial activity properties of PLA-g-MA and PLA/CS composites. Copyright © 2016 Elsevier B.V. All rights reserved.

Double-hydrophobic elastin-like polypeptides with added functional motifs: Self-assembly and cytocompatibility.

Science.gov (United States)

Le, Duc H T; Tsutsui, Yoko; Sugawara-Narutaki, Ayae; Yukawa, Hiroshi; Baba, Yoshinobu; Ohtsuki, Chikara

2017-09-01

We have recently developed a novel double-hydrophobic elastin-like triblock polypeptide called GPG, designed after the uneven distribution of two different hydrophobic domains found in elastin, an extracellular matrix protein providing elasticity and resilience to tissues. Upon temperature trigger, GPG undergoes a sequential self-assembling process to form flexible beaded nanofibers with high homogeneity and excellent dispersibility in water. Given that GPG might be a potential elastin-mimetic material, we sought to explore the biological activities of this block polypeptide. Besides GPG, several functionalized derivatives were also constructed by fusing functional motifs such as KAAK or KAAKGRGDS at the C-terminal of GPG. Although the added motifs affected the kinetics of fiber formation and β-sheet contents, all three GPGs assembled into beaded nanofibers at the physiological temperature. The resulting GPG nanofibers preserved their beaded structures in cell culture medium; therefore, they were coated on polystyrene substrates to study their cytocompatibility toward mouse embryonic fibroblasts, NIH-3T3. Among the three polypeptides, GPG having the cell-binding motif GRGDS derived from fibronectin showed excellent cell adhesion and cell proliferation properties compared to other conventional materials, suggesting its promising applications as extracellular matrices for mammalian cells. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 2475-2484, 2017. © 2017 Wiley Periodicals, Inc.

Circular braiding take-up speed generation using inverse kinematics

NARCIS (Netherlands)

van Ravenhorst, J.H.; Akkerman, Remko

2014-01-01

Circular overbraiding of composite preforms on complex mandrels currently lacks automatic generation of machine control data. To solve this limitation, an inverse kinematics-based procedure was designed and implemented for circular braiding machines with optional guide rings, resulting in a take-up

Pyrolytic carbon coating for cytocompatibility of titanium oxide nanoparticles: a promising candidate for medical applications.

NARCIS (Netherlands)

Behzadi, S.; Imani, M.; Yousefi, M.; Galinetto, P.; Simchi, A.; Amiri, H.; Stroeve, P.; Mahmoudi, M.

2012-01-01

Nanoparticles for biomedical use must be cytocompatible with the biological environment that they are exposed to. Current research has focused on the surface functionalization of nanoparticles by using proteins, polymers, thiols and other organic compounds. Here we show that inorganic nanoparticles

Low-Cost Behavioral Nudges Increase Medicaid Take-Up Among Eligible Residents Of Oregon.

Science.gov (United States)

Wright, Bill J; Garcia-Alexander, Ginny; Weller, Margarette A; Baicker, Katherine

2017-05-01

Efforts to reduce the ranks of the uninsured hinge on take-up of available programs and subsidies, but take-up of even free insurance is often less than complete. The evidence of the effectiveness of policies aiming to increase take-up is limited. We used a randomized controlled design to evaluate the impact of improved communication and behaviorally informed "nudges" designed to increase Medicaid take-up among eligible populations. Fielding randomized interventions in two different study populations in Oregon, we found that even very low-cost interventions substantially increased enrollment. Effects were larger in a population whose members had already expressed interest in obtaining coverage, but the effects were more persistent in low-income populations whose members were already enrolled in other state assistance programs but had not expressed interest in health insurance. The effects were similar across different demographic groups. Our results suggest that improving the design of enrollment processes and using low-cost mass-outreach efforts have the potential to substantially increase insurance coverage of vulnerable populations. Project HOPE—The People-to-People Health Foundation, Inc.

Modelling oral up-take of hydrophobic and super-hydrophobic chemicals in fish.

Science.gov (United States)

Larisch, Wolfgang; Goss, Kai-Uwe

2018-01-24

We have extended a recently published toxicokinetic model for fish (TK-fish) towards the oral up-take of contaminants. Validation with hydrophobic chemicals revealed that diffusive transport through aqueous boundary layers in the gastro-intestinal tract and in the blood is the limiting process. This process can only be modelled correctly if facilitated transport by albumin or bile micelles through these boundary layers is accounted for. In a case study we have investigated the up-take of a super hydrophobic chemical, Dechlorane Plus. Our results suggest that there is no indication of a hydrophobicity or size cut-off in the bioconcentration of this chemical. Based on an extremely high, but mechanistically sound facilitation factor we received model results in good agreement with experimental values from the literature. The results also indicate that established experimental procedures for BCF determination cannot cover the very slow up-take and clearance kinetics that are to be expected for such a chemical.

Phase assemblage study and cytocompatibility property of heat treated potassium magnesium phosphate-silicate ceramics.

Science.gov (United States)

Kumar, Ravi; Kalmodia, Sushma; Nath, Shekhar; Singh, Dileep; Basu, Bikramjit

2009-08-01

This article reports the study on a new generation bioactive ceramic, based on MgKPO(4) (Magnesium Potassium Phosphate, abbreviated as MKP) for biomedical applications. A series of heat treatment experiments on the slip cast silica (SiO(2)) containing MKP ceramics were carried out at 900, 1,000 and 1,100 degrees C for 4 h in air. The density of the slip cast ceramic increases to 2.5 gm/cm(3) upon heat treatment at 900 degrees C. However, no significant change in density is measured upon heat treatment to higher temperature of 1,000 and 1,100 degrees C. On the basis of XRD results, the presence of K(2)MgSi(5)O(12) and dehydrated MgKPO(4) were confirmed and complementary information has also been obtained using FT-IR and Raman spectroscopy. In order to confirm the in vitro cytocompatibility property, the cell culture tests were carried out on selected samples and the results reveal good cell adhesion and spreading of L929 mouse fibroblast cells. MTT assay analysis with L929 cells confirmed non-cytotoxic behavior of MKP containing ceramics and the results are comparable with sintered HAp ceramics. It is expected that the newly developed MKP based materials could be a good substitute for hydroxyapatite (HAp or HA) based bioceramics.

Hemocompatibility and cytocompatibility of pristine and plasma-treated silver-zeolite-chitosan composites

Science.gov (United States)

Taaca, Kathrina Lois M.; Vasquez, Magdaleno R.

2018-02-01

Silver-exchanged zeolite-chitosan (AgZ-Ch) composites with varying AgZ content were prepared by solvent casting and modified under argon (Ar) plasma excited by a 13.56 MHz radio frequency (RF) power source. Silver (Ag) was successfully incorporated in a natural zeolite host without losing its antibacterial activity against Escherichia coli and Staphylococcus aureus. The AgZ particles were incorporated into a chitosan matrix without making significant changes in the matrix structure. The composites also exhibited antibacterial sensitivity due to the inclusion of AgZ. Plasma treatment enhanced the surface wettability of polar and nonpolar test liquids of the composites. The average increase in total surface free energy after treatment was around 49% with the polar component having a significant change. Cytocompatibility tests showed at least 87% cell viability for pristine and plasma-treated composites comparable with supplemented RPMI as positive control. Hemocompatibility tests revealed that pristine composites does not promote hemolysis and the blood clotting ability is less than 10 min. Coupled with antibacterial property, the fabricated composites have promising biomedical applications.

Cytocompatibility and antibacterial properties of zirconia coatings with different silver contents on titanium

International Nuclear Information System (INIS)

Huang, Heng-Li; Chang, Yin-Yu; Chen, Ya-Chi; Lai, Chih-Ho; Chen, Michael Y.C.

2013-01-01

This study used a twin-gun magnetron sputtering system to deposit ZrO 2 -silver (Ag) coatings on biograde pure-titanium implant materials, and the Ag content in the deposited coatings was controlled by the magnetron power. The films were then annealed using rapid thermal annealing at 350 °C for 2 min to induce the nucleation and growth of nanoparticles on the film surface. Staphylococcus aureus (S. aureus) and Actinobacillus actinomycetemcomitans (A. actinomycetemcomitans) were used for in vitro antibacterial analyses. The cytocompatibility, mRNA expression, and adhesive morphology of human gingival fibroblast (HGF) cells on the coatings were also determined. The obtained results suggest that ZrO 2 -Ag composite coatings containing less than 10.6 at.% Ag show hydrophobicity, good viability and proliferation of HGF cells, and antibacterial effects on S. aureus and A. actinomycetemcomitans. Moreover, the antibacterial performance of ZrO 2 -Ag coatings is superior to that pure-titanium whilst maintaining biological compatibility. - Highlights: • The annealed ZrO 2 -Ag coatings showed a tetragonal-and-monoclinic structure. • Nanoparticles were well distributed in the annealed ZrO 2 -Ag composite coatings. • The ZrO 2 -Ag coated Ti showed hydrophobic feature. • The ZrO 2 -Ag showed good antibacterial performance. • The ZrO 2 -Ag showed good human gingival fibroblast cell viability

3D Printing of Cytocompatible Water-Based Light-Cured Polyurethane with Hyaluronic Acid for Cartilage Tissue Engineering Applications

Directory of Open Access Journals (Sweden)

Ming-You Shie

2017-02-01

Full Text Available Diseases in articular cartilages have affected millions of people globally. Although the biochemical and cellular composition of articular cartilages is relatively simple, there is a limitation in the self-repair ability of the cartilage. Therefore, developing strategies for cartilage repair is very important. Here, we report on a new liquid resin preparation process of water-based polyurethane based photosensitive materials with hyaluronic acid with application of the materials for 3D printed customized cartilage scaffolds. The scaffold has high cytocompatibility and is one that closely mimics the mechanical properties of articular cartilages. It is suitable for culturing human Wharton’s jelly mesenchymal stem cells (hWJMSCs and the cells in this case showed an excellent chondrogenic differentiation capacity. We consider that the 3D printing hybrid scaffolds may have potential in customized tissue engineering and also facilitate the development of cartilage tissue engineering.

3D Printing of Cytocompatible Water-Based Light-Cured Polyurethane with Hyaluronic Acid for Cartilage Tissue Engineering Applications

Science.gov (United States)

Shie, Ming-You; Chang, Wen-Ching; Wei, Li-Ju; Huang, Yu-Hsin; Chen, Chien-Han; Shih, Cheng-Ting; Chen, Yi-Wen; Shen, Yu-Fang

2017-01-01

Diseases in articular cartilages have affected millions of people globally. Although the biochemical and cellular composition of articular cartilages is relatively simple, there is a limitation in the self-repair ability of the cartilage. Therefore, developing strategies for cartilage repair is very important. Here, we report on a new liquid resin preparation process of water-based polyurethane based photosensitive materials with hyaluronic acid with application of the materials for 3D printed customized cartilage scaffolds. The scaffold has high cytocompatibility and is one that closely mimics the mechanical properties of articular cartilages. It is suitable for culturing human Wharton’s jelly mesenchymal stem cells (hWJMSCs) and the cells in this case showed an excellent chondrogenic differentiation capacity. We consider that the 3D printing hybrid scaffolds may have potential in customized tissue engineering and also facilitate the development of cartilage tissue engineering. PMID:28772498

Corrosion resistance and cytocompatibility of biodegradable surgical magnesium alloy coated with hydrogenated amorphous silicon.

Science.gov (United States)

Xin, Yunchang; Jiang, Jiang; Huo, Kaifu; Tang, Guoyi; Tian, Xiubo; Chu, Paul K

2009-06-01

The fast degradation rates in the physiological environment constitute the main limitation for the applications of surgical magnesium alloys as biodegradable hard-tissue implants. In this work, a stable and dense hydrogenated amorphous silicon coating (a-Si:H) with desirable bioactivity is deposited on AZ91 magnesium alloy using magnetron sputtering deposition. Raman spectroscopy and Fourier transform infrared spectroscopy reveal that the coating is mainly composed of hydrogenated amorphous silicon. The hardness of the coated alloy is enhanced significantly and the coating is quite hydrophilic as well. Potentiodynamic polarization results show that the corrosion resistance of the coated alloy is enhanced dramatically. In addition, the deterioration process of the coating in simulated body fluids is systematically investigated by open circuit potential evolution and electrochemical impedance spectroscopy. The cytocompatibility of the coated Mg is evaluated for the first time using hFOB1.19 cells and favorable biocompatibility is observed. 2008 Wiley Periodicals, Inc.

New Estimates of Offer and Take-Up of Employer-Sponsored Insurance.

Science.gov (United States)

Abramowitz, Joelle; O'Hara, Brett

2017-10-01

This analysis uses new questions in the Current Population Survey Annual Social and Economic Supplement to examine rates of offer and take-up of employer-sponsored health insurance over early 2014 and early 2015, as well as reasons reported for why individuals did not enroll. We find increases in offer and eligible rates of 0.5 and 0.9 percentage points, respectively, and a decrease in the take-up rate of 1.5 percentage points, while the coverage rate remained stable. We further find an increase in the proportion of workers covered by another plan and decreases in the proportions eligible for coverage but having a preexisting condition, employed as contract or temporary employees not allowed in the plan, and who have not yet worked for an employer long enough.

How does the surface treatment change the cytocompatibility of implants made by selective laser melting?

Science.gov (United States)

Matouskova, Lucie; Ackermann, Michal; Horakova, Jana; Capek, Lukas; Henys, Petr; Safka, Jiri

2018-04-01

The study investigates the potential for producing medical components via Selective Laser Melting technology (SLM). The material tested consisted of the biocompatible titanium alloy Ti6Al4V. The research involved the testing of laboratory specimens produced using SLM technology both in vitro and for surface roughness. The aim of the research was to clarify whether SLM technology affects the cytocompatibility of implants and, thus, whether SLM implants provide suitable candidates for medical use following zero or minimum post-fabrication treatment. Areas covered: The specimens were tested with an osteoblast cell line and, subsequently, two post-treatment processes were compared: non-treated (as-fabricated) and glass-blasted. Interactions with MG-63 cells were evaluated by means of metabolic MTT assay and microscope techniques (scanning electron microscopy, fluorescence microscopy). Surface roughness was observed on both the non-treated and glass-blasted SLM specimens. Expert Commentary: The research concluded that the glass-blasting of SLM Ti6Al4V significantly reduces surface roughness. The arithmetic mean roughness Ra was calculated at 3.4 µm for the glass-blasted and 13.3 µm for the non-treated surfaces. However, the results of in vitro testing revealed that the non-treated surface was better suited to cell growth.

Glyoxal Crosslinking of Cell-Seeded Chitosan/Collagen Hydrogels for Bone Regeneration

Science.gov (United States)

Wang, Limin; Stegemann, Jan P.

2011-01-01

Chitosan and collagen are natural biomaterials that have been used extensively in tissue engineering, both separately and as composite materials. Most methods to fabricate chitosan/collagen composites use freeze drying and chemical crosslinking to create stable porous scaffolds, which subsequently can be seeded with cells. In this study, we directly embedded human bone marrow stem cells (hBMSC) in chitosan/collagen materials by initiating gelation using β-glycerophosphate at physiological temperature and pH. We further examined the use of glyoxal, a dialdehyde with relatively low toxicity, to crosslink these materials and characterized the resulting changes in matrix and cell properties. The cytocompatibility of glyoxal and the crosslinked gels were investigated in terms of hBMSC metabolic activity, viability, proliferation, and osteogenic differentiation. These studies revealed that glyoxal was cytocompatible at concentrations below about 1 mM for periods of exposure up to 15 h, though the degree of cell spreading and proliferation were dependent on matrix composition. Glyoxal-crosslinked matrices were stiffer and compacted less than uncrosslinked controls. It was further demonstrated that hBMSC can attach and proliferate in 3D matrices composed of 50/50 chitosan/collagen, and that these materials supported osteogenic differentiation in response to stimulation. Such glyoxal-crosslinked chitosan/collagen composite materials may find utility as cell delivery vehicles for enhancing the repair of bone defects. PMID:21345389

Cable control and take-up mechanisms and x-ray scanning apparatus incorporating such mechanisms

International Nuclear Information System (INIS)

Braden, A.B.; Lekan, J.J.; Taylor, S.K.; Richey, J.B.

1977-01-01

In this patent, an invention for cable control and take-up mechanisms for elongated, flexible cables is described. Such cables are used in X-ray scanner apparatus to provide power, electronic signals and fluids. A detailed design and description is given of the cable harness, control and take-up mechanism that would be used in conjunction with an X-ray scanner. As a result of this invention, the cables are prevented from becoming prematurely worn or entangled in the X-ray apparatus during the rotational and translational movements necessary in tomographic examinations. This invention is also applicable to other types of apparatus and environments where a number of different positions is required and where it is necessary to control the take-up of elongated, flexible, cable-like members. (U.K.)

Cytocompatibility and early osseointegration of nanoTiO{sub 2}-modified Ti-24 Nb-4 Zr-7.9 Sn surfaces

Energy Technology Data Exchange (ETDEWEB)

Liu, X.H. [Department of Prosthodontics, China Medical University School of Stomatology, Shenyang (China); Wu, L., E-mail: wulin13@163.com [Department of Prosthodontics, China Medical University School of Stomatology, Shenyang (China); Ai, H.J. [Department of Prosthodontics, China Medical University School of Stomatology, Shenyang (China); Han, Y. [State Key laboratory for Mechanical Behaviour of Materials, Xi' an Jiaotong University, Xi' an (China); Hu, Y. [Department of Prosthodontics, China Medical University School of Stomatology, Shenyang (China)

2015-03-01

This study aimed to evaluate the cytocompatibility and early osseointegration of Ti-24 Nb-4 Zr-7.9 Sn (Ti-2448) surfaces that were modified with a nanoscale TiO{sub 2} coating. The coating was fabricated using a hydrothermal synthesis method to generate nanoTiO{sub 2}/Ti-2448. The surface characteristics of the samples were evaluated using scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and X-ray diffraction (XRD). The cytotoxicity of the fabricated nanoTiO{sub 2}/Ti-2448 was determined using MTT assays. The proliferation and alkaline phosphatase (ALP) activity of MC3T3-E1 osteoblasts cultured on nanoTiO{sub 2}/Ti-2448 were compared with those cultured on Ti-2448. Disk-shaped implants were placed in Wistar rats. The histological sections were stained with haematoxylin and eosin (HE), and the histocompatibility was analysed at 4 and 12 weeks post-implantation. Cylindrical implants were embedded in Japanese white rabbits, and the histological sections were stained with HE and anti-TGF-β1 to evaluate the histocompatibility and early osseointegration at 4, 12 and 26 weeks post-implantation. NanoTiO{sub 2}/Ti-2448 exhibited a rougher surface than did Ti-2448. NanoTiO{sub 2}/Ti-2448 was determined to be non-cytotoxic. More osteoblasts and higher ALP activity were observed for nanoTiO{sub 2}/Ti-2448 than Ti-2448 (p < 0.05). Few inflammatory cells were detected around nanoTiO{sub 2}/Ti-2448, and the expression of TGF-β1 on nanoTiO{sub 2}/Ti-2448 peaked at earlier time than that on Ti-2448. The results indicate that the cytocompatibility and early osseointegration were enhanced by the nanoTiO{sub 2} coating. - Highlights: • The cytocompatibility of nanoTiO2/Ti-2448 is first reported in our work. • The early osseointegration of nanoTiO2/Ti-2448 is first reported in our work. • We evaluate the biocompatibility of nanoTiO2/Ti-2448 by in-vitro and in-vivo tests.

Cross-linkable graphene oxide embedded nanocomposite hydrogel with enhanced mechanics and cytocompatibility for tissue engineering.

Science.gov (United States)

Liu, Xifeng; Miller, A Lee; Waletzki, Brian E; Lu, Lichun

2018-05-01

Graphene oxide (GO) is an attractive material that can be utilized to enhance the modulus and conductivities of substrates and hydrogels. To covalently cross-link graphene oxide sheets into hydrogels, abundant cross-linkable double bonds were introduced to synthesize the graphene-oxide-tris-acrylate sheet (GO-TrisA). Polyacrylamide (PAM) nanocomposite hydrogels were then fabricated with inherent covalently and permanently cross-linked GO-TrisA sheets. Results showed that the covalently cross-linked GO-TrisA/PAM nanocomposite hydrogel had enhanced mechanical strength, thermo stability compared with GO/PAM hydrogel maintained mainly by hydrogen bonding between PAM chains and GO sheets. In vitro cell study showed that the covalently cross-linked rGO-TrisA/PAM nanocomposite hydrogel had excellent cytocompatibility after in situ reduction. These results suggest that rGO-TrisA/PAM nanocomposite hydrogel holds great potential for tissue engineering applications. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1247-1257, 2018. © 2018 Wiley Periodicals, Inc.

Galvanic cells: setting up the Daniell cell.

OpenAIRE

Milla González, Miguel

2008-01-01

With the reagents (0.05M copper nitrate solution, 0.05M zinc nitrate solution) and material (glassware, potentiometer, electric wire) availabe in the laboratory, the user must set up the Daniell cell. Different configurations can be possible if the half cells are filled with either electrolyte solution. The cell connections to the measuring device can also be changed. In all instances, an explanation of the set up cell is obtained as well as of the measured potential difference.

Synthesis, characterization, and cytocompatibility of potential cockle shell aragonite nanocrystals for osteoporosis therapy and hormonal delivery

Directory of Open Access Journals (Sweden)

Jaji AZ

2017-01-01

at pH 7.5, enabling sustained slow release of PTH 1-34 for 168 h (1 week. A 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide cytocompatibility assay in Human Foetal Osteoblast Cell Line hFOB 1.19 showed that ANC can safely support osteoblast proliferation up to 48 h whereas PTH-ANC can safely support the proliferation at 72 h and beyond due to the sustained slow release of PTH 1-34. It was concluded that due to its biogenic nature, ANC is a cytocompatible antiosteoporotic agent. It doubles as a nanocarrier for the enhancement of efficacy and safety of the bone anabolic PTH 1-34. ANC is expected to reduce the cost, dosage, and dose frequency associated with the use of PTH 1-34 management of primary and secondary forms of osteoporosis. Keywords: bone, FESEM, FT-IR, MTT viability, PTH 1-34, sustained release, TEM, XRD, zeta potential

Effect of crosslinking functionality on microstructure, mechanical properties, and in vitro cytocompatibility of cellulose nanocrystals reinforced poly (vinyl alcohol)/sodium alginate hybrid scaffolds.

Science.gov (United States)

Kumar, Anuj; Lee, Yujin; Kim, Doyeon; Rao, Kummara Madhusudana; Kim, Jisoo; Park, Soyoung; Haider, Adnan; Lee, Do Hyun; Han, Sung Soo

2017-02-01

Cellulose nanocrystals reinforced poly (vinyl alcohol)/sodium alginate hybrid scaffolds were fabricated by using freeze casting and freeze drying method. In this study, the effect of crosslinking agents such as calcium chloride, orthophosphoric acid, and borax on morphological, structural, thermal, mechanical, and cytocompatibility (cell adhesion and proliferation) properties was investigated. The results showed that the change in type of crosslinking agent significantly changed the properties of the hybrid scaffolds. Based on this study, borax-crosslinked hybrid scaffold showed good fibrous porous structure with high porosity (95.2%), highest water uptake capacity, good thermal stability, mechanical stability (storage modulus), and in vitro cell adhesion and proliferation with fibroblast (NIH3T3) cells. This primarily research study explores the way for further use of this crosslinking agent to design and fabricate scaffolds for tissue engineering applications. Copyright © 2016 Elsevier B.V. All rights reserved.

Electrospun composite nanofiber membrane of poly(l-lactide) and surface grafted chitin whiskers: Fabrication, mechanical properties and cytocompatibility.

Science.gov (United States)

Liu, Hua; Liu, Wenjun; Luo, Binghong; Wen, Wei; Liu, Mingxian; Wang, Xiaoying; Zhou, Changren

2016-08-20

To improve both the mechanical properties and cytocompatibility of poly(l-lactide) (PLLA), rod-like chitin whiskers (CHWs) were prepared, and subsequently surface modified with l-lactide to obtain grafted CHWs (g-CHWs). Then, CHWs and g-CHWs were further introduced into PLLA matrix to fabricate CHWs/PLLA and g-CHWs/PLLA nanofiber membranes by electrospinning technique. Morphologies and properties of the CHWs and g-CHWs were characterized. The surface-grafted PLLA chains played an important role in improving interfacial interaction between the whiskers and PLLA matrix. The g-CHWs dispersed more uniformly in matrix than CHWs, and the as-prepared g-CHWs/PLLA nanofiber membrane showed relative smooth and uniform fiber. As a result, the tensile strength and modulus of the g-CHWs/PLLA nanofiber membrane were obviously superior to those of the pure PLLA and CHWs/PLLA nanofiber membranes. Cells culture results indicated that g-CHWs/PLLA nanofiber membrane is more effectively in promoting MC3T3-E1 cells adhesion, spreading and proliferation than pure PLLA and CHWs/PLLA nanofiber membrane. Copyright © 2016 Elsevier Ltd. All rights reserved.

In Situ Forming, Cytocompatible, and Self-Recoverable Tough Hydrogels Based on Dual Ionic and Click Cross-Linked Alginate.

Science.gov (United States)

Ghanian, Mohammad Hossein; Mirzadeh, Hamid; Baharvand, Hossein

2018-05-14

A dual cross-linking strategy was developed to answer the urgent need for fatigue-resistant, cytocompatible, and in situ forming tough hydrogels. Clickable, yet calcium-binding derivatives of alginate were synthesized by partial substitution of its carboxyl functionalities with furan, which could come into Diels-Alder click reaction with maleimide end groups of a four arm poly(ethylene glycol) cross-linker. Tuning the cooperative viscoelastic action of transient ionic and permanent click cross-links within the single network of alginate provided a soft tough hydrogel with a set of interesting features: (i) immediate self-recovery under cyclic loading, (ii) highly efficient and autonomous self-healing upon fracture, (iii) in situ forming ability for molding and minimally invasive injection, (iv) capability for viable cell encapsulation, and (v) reactivity for on-demand biomolecule conjugation. The facile strategy is applicable to a wide range of natural and synthetic polymers by introducing the calcium binding and click reacting functional groups and can broaden the use of tough hydrogels in load-bearing, cell-laden applications such as soft tissue engineering and bioactuators.

School and local authority characteristics associated with take-up of free school meals in Scottish secondary schools, 2014.

Science.gov (United States)

Chambers, Stephanie; Dundas, Ruth; Torsney, Ben

2016-01-02

School meals are an important state-delivered mechanism for improving children's diets. Scottish local authorities have a statutory duty to provide free school meals (FSM) to families meeting means-testing criteria. Inevitably take-up of FSM does not reach 100%. Explanations put forward to explain this include social stigma, as well as a more general dissatisfaction amongst pupils about lack of modern facilities and meal quality, and a preference to eat where friends are eating. This study investigated characteristics associated with take-up across Scottish secondary schools in 2013-2014 using multilevel modelling techniques. Results suggest that stigma, food quality and the ability to eat with friends are associated with greater take-up. Levels of school modernisation appeared less important, as did differences between more urban or rural areas. Future studies should focus on additional school-level variables to identify characteristics associated with take-up, with the aim of reducing the number of registered pupils not taking-up FSM.

Regular pattern formation on surface of aromatic polymers and its cytocompatibility

Energy Technology Data Exchange (ETDEWEB)

Michaljaničová, I. [Department of Solid State Engineering, University of Chemistry and Technology Prague, 166 28 Prague (Czech Republic); Slepička, P., E-mail: petr.slepicka@vscht.cz [Department of Solid State Engineering, University of Chemistry and Technology Prague, 166 28 Prague (Czech Republic); Rimpelová, S. [Department of Biochemistry and Microbiology, University of Chemistry and Technology Prague, Technicka 5, Prague 6, 166 28 (Czech Republic); Slepičková Kasálková, N.; Švorčík, V. [Department of Solid State Engineering, University of Chemistry and Technology Prague, 166 28 Prague (Czech Republic)

2016-05-01

Highlights: • The nanopatterning technique of PES, PEI and PEEK with KrF laser was described. • Both nanodots and ripples on aromatic polymers were successfully constructed. • Dimensions of nanostructures can be precisely controlled. • Surface parameters dependent on angle of laser beam incidence were characterized. • U-2 OS cell adaptation and growth on nanopatterned surface was described. - Abstract: In this work, we describe ripple and dot nanopatterning of three different aromatic polymer substrates by KrF excimer laser treatment. The conditions for regular structures were established by laser fluence and number of pulses. Subsequently, the influence of the angle of incidence of a laser beam was investigated. We have chosen polyethersulfone (PES), polyetherimide (PEI) and polyetheretherketone (PEEK) as substrates for modification since they are thermally, chemically and mechanically resistant aromatic polymers with high absorption coefficients at excimer laser wavelength. As a tool of wettability investigation, we used contact angle measurement and for determination of the absorption edge, UV–vis spectroscopy was used. Material surface chemistry was analyzed using FTIR and the changes caused by modification were gained as differential spectra by subtraction of the spectra of non-modified material. Surface morphology was investigated by atomic force microscopy, also the roughness and surface area of modified samples were studied. The scans showed the formation of regular periodic structures, ripples and dots, after treatment by 8 and 16 mJ cm{sup −2} and 6000 pulses. Further, initial in vitro cytocompatibility tests were performed using U-2 OS cell line growing on PES samples subjected to scanning electron microscopy analysis. The structure formation mapping contributes strongly to development of new applications using nanostructured polymers, e.g. in tissue engineering or in combination with metallization in selected electronics and metamaterials

Niobium-Doped Hydroxyapatite Bioceramics: Synthesis, Characterization and In Vitro Cytocompatibility

Directory of Open Access Journals (Sweden)

Nádia S. V. Capanema

2015-07-01

Full Text Available Doping calcium phosphates with ionic species can play an important role in biological responses promoting alkaline phosphatase activity, and, therefore inducing the generation of new bone. Thus, in this study, the synthesis of niobium-doped hydroxyapatite (Nb-HA nanosize particles obtained by the precipitation process in aqueous media followed by thermal treatment is presented. The bioceramics were extensively characterized by X-ray diffraction, wavelength dispersive X-ray fluorescence spectrometry, Fourier transform infrared spectroscopy, scanning electron microscopy/energy dispersive X-ray spectroscopy analysis, transmission electron microscopy, atomic force microscopy and thermal analysis regarding their chemical composition, structure and morphology. The results showed that the precipitate dried at 110 °C was composed of amorphous calcium phosphate and HA, with polidisperse particles ranging from micro to nano dimensions. After the thermal treatment at 900 °C, the bioceramic system evolved predominantly to HA crystalline phase, with evident features of particle sintering and reduction of surface area. Moreover, the addition of 10 mol% of niobium salt precursor during the synthesis indicated the complete incorporation of the Nb(V species in the HA crystals with detectable changes in the original lattice parameters. Furthermore, the incorporation of Nb ions caused a significant refinement on the average particle size of HA. Finally, the preliminary cytocompatibility response of the biomaterials was accessed by human osteoblast cell culture using MTT and resazurin assays, which demonstrated no cytotoxicity of the Nb-alloyed hydroxyapatite. Thus, these findings seem promising for developing innovative Nb-doped calcium phosphates as artificial biomaterials for potential use in bone replacements and repair.

Toughening of Thermoresponsive Arrested Networks of Elastin-Like Polypeptides To Engineer Cytocompatible Tissue Scaffolds.

Science.gov (United States)

Glassman, Matthew J; Avery, Reginald K; Khademhosseini, Ali; Olsen, Bradley D

2016-02-08

Formulation of tissue engineering or regenerative scaffolds from simple bioactive polymers with tunable structure and mechanics is crucial for the regeneration of complex tissues, and hydrogels from recombinant proteins, such as elastin-like polypeptides (ELPs), are promising platforms to support these applications. The arrested phase separation of ELPs has been shown to yield remarkably stiff, biocontinuous, nanostructured networks, but these gels are limited in applications by their relatively brittle nature. Here, a gel-forming ELP is chain-extended by telechelic oxidative coupling, forming extensible, tough hydrogels. Small angle scattering indicates that the chain-extended polypeptides form a fractal network of nanoscale aggregates over a broad concentration range, accessing moduli ranging from 5 kPa to over 1 MPa over a concentration range of 5-30 wt %. These networks exhibited excellent erosion resistance and allowed for the diffusion and release of encapsulated particles consistent with a bicontinuous, porous structure with a broad distribution of pore sizes. Biofunctionalized, toughened networks were found to maintain the viability of human mesenchymal stem cells (hMSCs) in 2D, demonstrating signs of osteogenesis even in cell media without osteogenic molecules. Furthermore, chondrocytes could be readily mixed into these gels via thermoresponsive assembly and remained viable in extended culture. These studies demonstrate the ability to engineer ELP-based arrested physical networks on the molecular level to form reinforced, cytocompatible hydrogel matrices, supporting the promise of these new materials as candidates for the engineering and regeneration of stiff tissues.

[Factors conditioning taking up sport activity by disabled people].

Science.gov (United States)

Plinta, Ryszard; Sobiecka, Joanna

2002-01-01

The aim of the study was to answer the following questions: What factors determine that disabled people take up systematic sport activity or should make such a decision? What reasons are able to eliminate the handicapped from process of regular going in for sport? Three groups of men participated. The group of disabled sportsmen included 39 subjects, the group of non-active disabled people 36 subjects and the group of able-bodied students 45 subjects. All the involved people answered the questions of the questionnaire, which concerned factors associated with sport activity of the handicapped and their socio-demographic characteristics, among other things. The opportunity of improvement of the health status is the main advantage of the sport for disabled people (53%). The chance of self-testing and sport competition was pointed out by 47% of subjects. The most common reason for taking up sport activity was sport passion (over 50%). The others were: possibility of creating new contacts with people, improvement of the physical condition, chance of self-testing and passing free time (23%). The lack of free time was the factor eliminating from sport activity in the second group (28%). The other problem was the shortage of appropriate clubs, equipment, infrastructure etc. (almost 25%). Students concluded that sport for disabled people aims to improve the mental condition mainly (42%). Quite similar percentage of the group (38%) didn't see any reason that was able to exclude the handicapped from goingin for sport. (1) Not only does active going in for sport improve the physical condition of the handicapped but strengthen them psychically as well. (2) The lack of sport activity in disabled people is to a high degree a result of low number of sport clubs, organisations, buildings as well as presence of architectural barriers.

Effects of halloysite nanotubes on physical properties and cytocompatibility of alginate composite hydrogels.

Science.gov (United States)

Huang, Biao; Liu, Mingxian; Long, Zheru; Shen, Yan; Zhou, Changren

2017-01-01

Sodium alginate (SA)/halloysite nanotubes (HNTs) composite hydrogels were successfully prepared by solution blending and cross-linking with calcium ions. HNTs can improve the physical properties and cytocompatibility of composite hydrogels. The static and shear viscosity of SA/HNTs solution increase by the addition of HNTs. FTIR suggests the presence of hydrogen bond interactions between HNTs and SA. The crystal structure of HNTs is retained in the composites as showed by the X-ray diffraction result. A porous structure with pore size of 100-250μm is found in the hydrogels, which can provide a space for cell growth and migration. The compressive mechanical properties of composite hydrogels significantly increase compared to the pure SA hydrogel. The SA/HNTs composite hydrogels with 80% HNTs loading exhibit the compressive stress at 80% strain of 2.99MPa, while the stress at 80% strain of pure SA hydrogel is only 0.8MPa. The dynamic storage modulus of composite hydrogels also markedly increases with HNTs concentration. The differential scanning calorimetry endothermic peak area and swelling ratios in NaCl solution of the composite hydrogels decrease by the addition of HNTs. Preosteoblast (MC3T3-E1) culture results reveal that the SA/HNTs composites especially at relatively low HNTs loading show a significant increase in cells adhesion and proliferation compared to the pure SA hydrogel. All the results demonstrate that the SA/HNTs composite hydrogels show a promising application in bone tissue engineering. Copyright © 2016 Elsevier B.V. All rights reserved.

Effects of halloysite nanotubes on physical properties and cytocompatibility of alginate composite hydrogels

Energy Technology Data Exchange (ETDEWEB)

Huang, Biao; Liu, Mingxian, E-mail: liumx@jnu.edu.cn; Long, Zheru; Shen, Yan; Zhou, Changren, E-mail: tcrz9@jnu.edu.cn

2017-01-01

Sodium alginate (SA)/halloysite nanotubes (HNTs) composite hydrogels were successfully prepared by solution blending and cross-linking with calcium ions. HNTs can improve the physical properties and cytocompatibility of composite hydrogels. The static and shear viscosity of SA/HNTs solution increase by the addition of HNTs. FTIR suggests the presence of hydrogen bond interactions between HNTs and SA. The crystal structure of HNTs is retained in the composites as showed by the X-ray diffraction result. A porous structure with pore size of 100–250 μm is found in the hydrogels, which can provide a space for cell growth and migration. The compressive mechanical properties of composite hydrogels significantly increase compared to the pure SA hydrogel. The SA/HNTs composite hydrogels with 80% HNTs loading exhibit the compressive stress at 80% strain of 2.99 MPa, while the stress at 80% strain of pure SA hydrogel is only 0.8 MPa. The dynamic storage modulus of composite hydrogels also markedly increases with HNTs concentration. The differential scanning calorimetry endothermic peak area and swelling ratios in NaCl solution of the composite hydrogels decrease by the addition of HNTs. Preosteoblast (MC3T3-E1) culture results reveal that the SA/HNTs composites especially at relatively low HNTs loading show a significant increase in cells adhesion and proliferation compared to the pure SA hydrogel. All the results demonstrate that the SA/HNTs composite hydrogels show a promising application in bone tissue engineering. - Highlights: • Alginate/HNTs composite hydrogels were fabricated using Ca{sup 2+} cross-linking method. • The hydrogen bond interactions between HNTs and alginate are confirmed. • HNTs can significantly enhance the mechanical properties of alginate hydrogel. • HNTs can improve the cell attachment and proliferation of alginate.

Effects of halloysite nanotubes on physical properties and cytocompatibility of alginate composite hydrogels

International Nuclear Information System (INIS)

Huang, Biao; Liu, Mingxian; Long, Zheru; Shen, Yan; Zhou, Changren

2017-01-01

Sodium alginate (SA)/halloysite nanotubes (HNTs) composite hydrogels were successfully prepared by solution blending and cross-linking with calcium ions. HNTs can improve the physical properties and cytocompatibility of composite hydrogels. The static and shear viscosity of SA/HNTs solution increase by the addition of HNTs. FTIR suggests the presence of hydrogen bond interactions between HNTs and SA. The crystal structure of HNTs is retained in the composites as showed by the X-ray diffraction result. A porous structure with pore size of 100–250 μm is found in the hydrogels, which can provide a space for cell growth and migration. The compressive mechanical properties of composite hydrogels significantly increase compared to the pure SA hydrogel. The SA/HNTs composite hydrogels with 80% HNTs loading exhibit the compressive stress at 80% strain of 2.99 MPa, while the stress at 80% strain of pure SA hydrogel is only 0.8 MPa. The dynamic storage modulus of composite hydrogels also markedly increases with HNTs concentration. The differential scanning calorimetry endothermic peak area and swelling ratios in NaCl solution of the composite hydrogels decrease by the addition of HNTs. Preosteoblast (MC3T3-E1) culture results reveal that the SA/HNTs composites especially at relatively low HNTs loading show a significant increase in cells adhesion and proliferation compared to the pure SA hydrogel. All the results demonstrate that the SA/HNTs composite hydrogels show a promising application in bone tissue engineering. - Highlights: • Alginate/HNTs composite hydrogels were fabricated using Ca 2+ cross-linking method. • The hydrogen bond interactions between HNTs and alginate are confirmed. • HNTs can significantly enhance the mechanical properties of alginate hydrogel. • HNTs can improve the cell attachment and proliferation of alginate.

Exploring grade 3 teachers' resistance to `take up' progressive mathematics teaching roles

Science.gov (United States)

Westaway, Lise; Graven, Mellony

2018-03-01

This article addresses the question: Why teachers of mathematics have yet to `take up' progressive roles? Drawing on the philosophy of critical realism and its methodological equivalent, social realism, we analyse interview and observation data of four grade 3 teachers, with the view to identifying the mechanisms conditioning the expression of teachers' identities. In so doing, we show how post-apartheid changes in systemic roles of teachers create contradictory tensions for teachers as these bring their own mathematical learning and teaching experiences into contradiction with the new post-apartheid roles they are mandated to enact. We examine how this contradiction, together with beliefs about mathematics, pedagogy and learners, is expressed in the teaching of grade 3 mathematics. We maintain that the complementarity between teachers' beliefs and old systemic roles provides an explanation for why teachers of grade 3 mathematics have yet to `take-up' progressive roles. The implications point to the need for teacher development that creates enablers that lead to changes in classroom practices that align with policy-designated, progressive roles in teaching mathematics.

In vitro and in vivo corrosion, cytocompatibility and mechanical properties of biodegradable Mg-Y-Ca-Zr alloys as implant materials.

Science.gov (United States)

Chou, Da-Tren; Hong, Daeho; Saha, Partha; Ferrero, Jordan; Lee, Boeun; Tan, Zongqing; Dong, Zhongyun; Kumta, Prashant N

2013-11-01

This study introduces a class of biodegradable Mg-Y-Ca-Zr alloys novel to biological applications and presents evaluations for orthopedic and craniofacial implant applications. Mg-Y-Ca-Zr alloys were processed using conventional melting and casting techniques. The effects of increasing Y content from 1 to 4 wt.% as well as the effects of T4 solution treatment were assessed. Basic material phase characterization was conducted using X-ray diffraction, optical microscopy and scanning electron microscopy. Compressive and tensile tests allowed for the comparison of mechanical properties of the as-cast and T4-treated Mg-Y-Ca-Zr alloys to pure Mg and as-drawn AZ31. Potentiodynamic polarization tests and mass loss immersion tests were used to evaluate the corrosion behavior of the alloys. In vitro cytocompatibility tests on MC3T3-E1 pre-osteoblast cells were also conducted. Finally, alloy pellets were implanted into murine subcutaneous tissue to observe in vivo corrosion as well as local host response through H&E staining. SEM/EDS analysis showed that secondary phase intermetallics rich in yttrium were observed along the grain boundaries, with the T4 solution treatment diffusing the secondary phases into the matrix while increasing the grain size. The alloys demonstrated marked improvement in mechanical properties over pure Mg. Increasing the Y content contributed to improved corrosion resistance, while solution-treated alloys resulted in lower strength and compressive strain compared to as-cast alloys. The Mg-Y-Ca-Zr alloys demonstrated excellent in vitro cytocompatibility and normal in vivo host response. The mechanical, corrosion and biological evaluations performed in this study demonstrated that Mg-Y-Ca-Zr alloys, especially with the 4 wt.% Y content, would perform well as orthopedic and craniofacial implant biomaterials. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Preparation, physical-chemical characterisation and cytocompatibility of calcium carbonate cements.

Science.gov (United States)

Combes, C; Miao, Baoji; Bareille, Reine; Rey, Christian

2006-03-01

The feasibility of calcium carbonate cements involving the recrystallisation of metastable calcium carbonate varieties has been demonstrated. Calcium carbonate cement compositions presented in this paper can be prepared straightforwardly by simply mixing water (liquid phase) with two calcium carbonate phases (solid phase) which can be easily obtained by precipitation. An original cement composition was obtained by mixing amorphous calcium carbonate and vaterite with an aqueous medium. The cement set and hardened within 2h at 37 degrees C in an atmosphere saturated with water and the final composition of the cement consisted mostly of aragonite. The hardened cement was microporous and showed poor mechanical properties. Cytotoxicity tests revealed excellent cytocompatibility of calcium carbonate cement compositions. Calcium carbonates with a higher solubility than the apatite formed for most of the marketed calcium phosphate cements might be of interest to increase biomedical cement resorption rates and to favour its replacement by bone tissue.

Chemically crosslinked nanogels of PEGylated poly ethyleneimine (L-histidine substituted) synthesized via metal ion coordinated self-assembly for delivery of methotrexate: Cytocompatibility, cellular delivery and antitumor activity in resistant cells

Energy Technology Data Exchange (ETDEWEB)

Abolmaali, Samira Sadat, E-mail: s.abolmaali@gmail.com [Pharmaceutical Nanotechnology Department, Shiraz University of Medical Sciences, Shiraz 71345 (Iran, Islamic Republic of); Tamaddon, Ali Mohammad, E-mail: amtamadon@gmail.com [Center for Nanotechnology in Drug Delivery, Shiraz University of Medical Sciences, Shiraz 71345 (Iran, Islamic Republic of); Mohammadi, Samaneh, E-mail: samaneh.mohammadi1986@gmail.com [Center for Nanotechnology in Drug Delivery, Shiraz University of Medical Sciences, Shiraz 71345 (Iran, Islamic Republic of); Amoozgar, Zohreh, E-mail: zohreh_amoozgar@dfci.harvard.edu [Department of Cancer Immunology and Aids, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA 02115 (United States); Dinarvand, Rasoul, E-mail: dinarvand@tums.ac.ir [Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran 14174 (Iran, Islamic Republic of)

2016-05-01

Self-assembled nanogels were engineered by forming Zn{sup 2+}-coordinated micellar templates of PEGylated poly ethyleneimine (PEG-g-PEI), chemical crosslinking and subsequent removal of the metal ion. Creation of stable micellar templates is a crucial step for preparing the nanogels. To this aim, imidazole moieties were introduced to the polymer by Fmoc-L-histidine using carbodiimide chemistry. It was hypothesized the nanogels loaded with methotrexate (MTX), a chemotherapeutic agent, circumvent impaired carrier activity in HepG2 cells (MTX-resistant hepatocellular carcinoma). So, the nanogels were post-loaded with MTX and characterized by {sup 1}H-NMR, FTIR, dynamic light scattering-zeta potential, atomic force microscopy, and drug release experiments. Cellular uptake and the antitumor activity of MTX-loaded nanogels were investigated by flow cytometry and MTT assay. Discrete, spherical and uniform nanogels, with sizes about 77–83 nm and a relatively high drug loading (54 ± 4% w/w), showed a low polydispersity and neutral surface charges. The MTX-loaded nanogels, unlike empty nanogels, lowered viability of HepG2 cells; the nanogels demonstrated cell-cycle arrest and apoptosis comparably higher than MTX as free drug that was shown to be through i) cellular uptake of the nanogels by clathrin-mediated transport and ii) endosomolytic activity of the nanogels in HepG2 cells. These findings indicate the potential antitumor application of this preparation, which has to be investigated in-vivo. - Highlights: • Nanogel synthesis through chemical crosslinking of the transition metal ion coordinated polymer self-assembly • An enhanced cytocompatibility if compared to unmodified polymer • A noticeable endocytic cellular internalization and endosomolytic activity • A specific antitumor cytotoxicity, cell cycle arrest and apoptosis in resistant tumor cells.

40 CFR 141.563 - What follow-up action is my system required to take based on continuous turbidity monitoring?

Science.gov (United States)

2010-07-01

... required to take based on continuous turbidity monitoring? 141.563 Section 141.563 Protection of... Individual Filter Turbidity Requirements § 141.563 What follow-up action is my system required to take based on continuous turbidity monitoring? Follow-up action is required according to the following tables...

Composite bone cements loaded with a bioactive and ferrimagnetic glass-ceramic: Leaching, bioactivity and cytocompatibility.

Science.gov (United States)

Verné, Enrica; Bruno, Matteo; Miola, Marta; Maina, Giovanni; Bianco, Carlotta; Cochis, Andrea; Rimondini, Lia

2015-08-01

In this work, composite bone cements, based on a commercial polymethylmethacrylate matrix (Palamed®) loaded with ferrimagnetic bioactive glass-ceramic particles (SC45), were produced and characterized in vitro. The ferrimagnetic bioactive glass-ceramic belongs to the system SiO2-Na2O-CaO-P2O5-FeO-Fe2O3 and contains magnetite (Fe3O4) crystals into a residual amorphous bioactive phase. Three different formulations (containing 10, 15 and 20 wt.% of glass-ceramic particles respectively) have been investigated. These materials are intended to be applied as bone fillers for the hyperthermic treatment of bone tumors. The morphological, compositional, calorimetric and mechanical properties of each formulation have been already discussed in a previous paper. The in vitro properties of the composite bone cements described in the present paper are related to iron ion leaching test (by graphite furnace atomic absorption spectrometer), bioactivity (i.e. the ability to stimulate the formation of a hydroxyapatite - HAp - layer on their surface after soaking in simulated body fluid SBF) and cytocompatibility toward human osteosarcoma cells (ATCC CRL-1427, Mg63). Morphological and chemical characterizations by scanning electron microscopy and energy dispersion spectrometry have been performed on the composite samples after each test. The iron release was negligible and all the tested samples showed the growth of HAp on their surface after 28 days of immersion in a simulated body fluid (SBF). Cells showed good viability, morphology, adhesion, density and the ability to develop bridge-like structures on all investigated samples. A synergistic effect between bioactivity and cell mineralization was also evidenced. Copyright © 2015 Elsevier B.V. All rights reserved.

Poly(hydroxybutyrate)/cellulose acetate blend nanofiber scaffolds: Preparation, characterization and cytocompatibility

Energy Technology Data Exchange (ETDEWEB)

Zhijiang, Cai, E-mail: caizhijiang@hotmail.com [School of Textiles, Tianjin Polytechnic University, Tianjin 300387 (China); State Key Laboratory of Hollow Fiber Membrane Material and Processes, No 399 BingShuiXi Street, XiQing District, Tianjin, China, 300387 (China); Yi, Xu; Haizheng, Yang; Jia, Jianru; Liu, Yuanpei [School of Textiles, Tianjin Polytechnic University, Tianjin 300387 (China)

2016-01-01

Poly(hydroxybutyrate) (PHB)/cellulose acetate (CA) blend nanofiber scaffolds were fabricated by electrospinning using the blends of chloroform and DMF as solvent. The blend nanofiber scaffolds were characterized by SEM, FTIR, XRD, DSC, contact angle and tensile test. The blend nanofibers exhibited cylindrical, uniform, bead-free and random orientation with the diameter ranged from 80–680 nm. The scaffolds had very well interconnected porous fibrous network structure and large aspect surface areas. It was found that the presence of CA affected the crystallization of PHB due to formation of intermolecular hydrogen bonds, which restricted the preferential orientation of PHB molecules. The DSC result showed that the PHB and CA were miscible in the blend nanofiber. An increase in the glass transition temperature was observed with increasing CA content. Additionally, the mechanical properties of blend nanofiber scaffolds were largely influenced by the weight ratio of PHB/CA. The tensile strength, yield strength and elongation at break of the blend nanofiber scaffolds increased from 3.3 ± 0.35 MPa, 2.8 ± 0.26 MPa, and 8 ± 0.77% to 5.05 ± 0.52 MPa, 4.6 ± 0.82 MPa, and 17.6 ± 1.24% by increasing PHB content from 60% to 90%, respectively. The water contact angle of blend nanofiber scaffolds decreased about 50% from 112 ± 2.1° to 60 ± 0.75°. The biodegradability was evaluated by in vitro degradation test and the results revealed that the blend nanofiber scaffolds showed much higher degradation rates than the neat PHB. The cytocompatibility of the blend nanofiber scaffolds was preliminarily evaluated by cell adhesion studies. The cells incubated with PHB/CA blend nanofiber scaffold for 48 h were capable of forming cell adhesion and proliferation. It showed much better biocompatibility than pure PHB film. Thus, the prepared PHB/CA blend nanofiber scaffolds are bioactive and may be more suitable for cell proliferation suggesting that these scaffolds can be used for

Composite bone cements loaded with a bioactive and ferrimagnetic glass-ceramic: Leaching, bioactivity and cytocompatibility

International Nuclear Information System (INIS)

Verné, Enrica; Bruno, Matteo; Miola, Marta; Maina, Giovanni; Bianco, Carlotta; Cochis, Andrea; Rimondini, Lia

2015-01-01

In this work, composite bone cements, based on a commercial polymethylmethacrylate matrix (Palamed®) loaded with ferrimagnetic bioactive glass-ceramic particles (SC45), were produced and characterized in vitro. The ferrimagnetic bioactive glass-ceramic belongs to the system SiO 2 –Na 2 O–CaO–P 2 O 5 –FeO–Fe 2 O 3 and contains magnetite (Fe 3 O 4 ) crystals into a residual amorphous bioactive phase. Three different formulations (containing 10, 15 and 20 wt.% of glass-ceramic particles respectively) have been investigated. These materials are intended to be applied as bone fillers for the hyperthermic treatment of bone tumors. The morphological, compositional, calorimetric and mechanical properties of each formulation have been already discussed in a previous paper. The in vitro properties of the composite bone cements described in the present paper are related to iron ion leaching test (by graphite furnace atomic absorption spectrometer), bioactivity (i.e. the ability to stimulate the formation of a hydroxyapatite – HAp – layer on their surface after soaking in simulated body fluid SBF) and cytocompatibility toward human osteosarcoma cells (ATCC CRL-1427, Mg63). Morphological and chemical characterizations by scanning electron microscopy and energy dispersion spectrometry have been performed on the composite samples after each test. The iron release was negligible and all the tested samples showed the growth of HAp on their surface after 28 days of immersion in a simulated body fluid (SBF). Cells showed good viability, morphology, adhesion, density and the ability to develop bridge-like structures on all investigated samples. A synergistic effect between bioactivity and cell mineralization was also evidenced. - Highlights: • An in vitro biological characterization was carried out on ferromagnetic and bioactive composite cements. • No release of iron was revealed in the physiological solution. • Bioactivity tests show hydroxyapatite precipitates

Composite bone cements loaded with a bioactive and ferrimagnetic glass-ceramic: Leaching, bioactivity and cytocompatibility

Energy Technology Data Exchange (ETDEWEB)

Verné, Enrica, E-mail: enrica.verne@polito.it [Institute of Materials Physics and Engineering, Applied Science and Technology Department, Politecnico di Torino, C. so Duca degli Abruzzi 24, 10129 Torino (Italy); Bruno, Matteo [Institute of Materials Physics and Engineering, Applied Science and Technology Department, Politecnico di Torino, C. so Duca degli Abruzzi 24, 10129 Torino (Italy); Miola, Marta [Institute of Materials Physics and Engineering, Applied Science and Technology Department, Politecnico di Torino, C. so Duca degli Abruzzi 24, 10129 Torino (Italy); Department of Health Sciences, Università del Piemonte Orientale “Amedeo Avogadro”, Via Solaroli 17, 28100 Novara (Italy); Maina, Giovanni; Bianco, Carlotta [Traumatology Orthopedics and Occupational Medicine Dept., Università di Torino, Via G. Zuretti 29, 10126 Torino (Italy); Cochis, Andrea [Department of Health Sciences, Università del Piemonte Orientale “Amedeo Avogadro”, Via Solaroli 17, 28100 Novara (Italy); Rimondini, Lia [Department of Health Sciences, Università del Piemonte Orientale “Amedeo Avogadro”, Via Solaroli 17, 28100 Novara (Italy); Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali, Via G. Giusti, 9, 50121 Firenze (Italy)

2015-08-01

In this work, composite bone cements, based on a commercial polymethylmethacrylate matrix (Palamed®) loaded with ferrimagnetic bioactive glass-ceramic particles (SC45), were produced and characterized in vitro. The ferrimagnetic bioactive glass-ceramic belongs to the system SiO{sub 2}–Na{sub 2}O–CaO–P{sub 2}O{sub 5}–FeO–Fe{sub 2}O{sub 3} and contains magnetite (Fe{sub 3}O{sub 4}) crystals into a residual amorphous bioactive phase. Three different formulations (containing 10, 15 and 20 wt.% of glass-ceramic particles respectively) have been investigated. These materials are intended to be applied as bone fillers for the hyperthermic treatment of bone tumors. The morphological, compositional, calorimetric and mechanical properties of each formulation have been already discussed in a previous paper. The in vitro properties of the composite bone cements described in the present paper are related to iron ion leaching test (by graphite furnace atomic absorption spectrometer), bioactivity (i.e. the ability to stimulate the formation of a hydroxyapatite – HAp – layer on their surface after soaking in simulated body fluid SBF) and cytocompatibility toward human osteosarcoma cells (ATCC CRL-1427, Mg63). Morphological and chemical characterizations by scanning electron microscopy and energy dispersion spectrometry have been performed on the composite samples after each test. The iron release was negligible and all the tested samples showed the growth of HAp on their surface after 28 days of immersion in a simulated body fluid (SBF). Cells showed good viability, morphology, adhesion, density and the ability to develop bridge-like structures on all investigated samples. A synergistic effect between bioactivity and cell mineralization was also evidenced. - Highlights: • An in vitro biological characterization was carried out on ferromagnetic and bioactive composite cements. • No release of iron was revealed in the physiological solution. • Bioactivity tests

Modulation of Protein Adsorption and Cell Proliferation on Polyethylene Immobilized Graphene Oxide Reinforced HDPE Bionanocomposites.

Science.gov (United States)

Upadhyay, Rahul; Naskar, Sharmistha; Bhaskar, Nitu; Bose, Suryasarathi; Basu, Bikramjit

2016-05-18

The uniform dispersion of nanoparticles in a polymer matrix, together with an enhancement of interfacial adhesion is indispensable toward achieving better mechanical properties in the nanocomposites. In the context to biomedical applications, the type and amount of nanoparticles can potentially influence the biocompatibility. To address these issues, we prepared high-density polyethylene (HDPE) based composites reinforced with graphene oxide (GO) by melt mixing followed by compression molding. In an attempt to tailor the dispersion and to improve the interfacial adhesion, we immobilized polyethylene (PE) onto GO sheets by nucleophilic addition-elimination reaction. A good combination of yield strength (ca. 20 MPa), elastic modulus (ca. 600 MPa), and an outstanding elongation at failure (ca. 70%) were recorded with 3 wt % polyethylene grafted graphene oxide (PE-g-GO) reinforced HDPE composites. Considering the relevance of protein adsorption as a biophysical precursor to cell adhesion, the protein adsorption isotherms of bovine serum albumin (BSA) were determined to realize three times higher equilibrium constant (Keq) for PE-g-GO-reinforced HDPE composites as compared to GO-reinforced composites. To assess the cytocompatibility, we grew osteoblast cell line (MC3T3) and human mesenchymal stem cells (hMSCs) on HDPE/GO and HDPE/PE-g-GO composites, in vitro. The statistically significant increase in metabolically active cell over different time periods in culture for up to 6 days in MC3T3 and 7 days for hMSCs was observed, irrespective of the substrate composition. Such observation indicated that HDPE with GO or PE-g-GO addition (up to 3 wt %) can be used as cell growth substrate. The extensive proliferation of cells with oriented growth pattern also supported the fact that tailored GO addition can support cellular functionality in vitro. Taken together, the experimental results suggest that the PE-g-GO in HDPE can effectively be utilized to enhance both mechanical and

Multistaged Nanovaccines Based on Porous Silicon@Acetalated Dextran@Cancer Cell Membrane for Cancer Immunotherapy

DEFF Research Database (Denmark)

Fontana, Flavia; Shahbazi, Mohammad Ali; Liu, Dongfei

2017-01-01

nanoparticles presented high monodispersity due to the efficient mixing produced in the microfluidic device and were shown to be highly cytocompatible over two human immortalized cell lines, KG1 and BDCM. Moreover, the nanoparticles induced the expression of co-stimulatory signals both in the immortal cell...

Effect of barium-coated halloysite nanotube addition on the cytocompatibility, mechanical and contrast properties of poly(methyl methacrylate) cement.

Science.gov (United States)

Jammalamadaka, Uday; Tappa, Karthik; Weisman, Jeffery A; Nicholson, James Connor; Mills, David K

2017-01-01

Halloysite nanotubes (HNTs) were investigated as a platform for tunable nanoparticle composition and enhanced opacity in poly(methyl methacrylate) (PMMA) bone cement. Halloysite has been widely used to increase the mechanical properties of various polymer matrices, in stark contrast to other fillers such as barium sulfate that provide opacity but also decrease mechanical strength. The present work describes a dry deposition method for successively fabricating barium sulfate nanoparticles onto the exterior surface of HNTs. A sintering process was used to coat the HNTs in barium sulfate. Barium sulfate-coated HNTs were then added to PMMA bone cement and the samples were tested for mechanical strength and tailored opacity correlated with the fabrication ratio and the amount of barium sulfate-coated HNTs added. The potential cytotoxic effect of barium-coated HNTs in PMMA cement was also tested on osteosarcoma cells. Barium-coated HNTs were found to be completely cytocompatible, and cell proliferation was not inhibited after exposure to the barium-coated HNTs embedded in PMMA cement. We demonstrate a simple method for the creation of barium-coated nanoparticles that imparted improved contrast and material properties to native PMMA. An easy and efficient method for coating clay nanotubes offers the potential for enhanced imaging by radiologists or orthopedic surgeons.

Factors associated with universal infant free school meal take up and refusal in a multicultural urban community.

Science.gov (United States)

Goodchild, G A; Faulks, J; Swift, J A; Mhesuria, J; Jethwa, P; Pearce, J

2017-08-01

Universal infant free school meals (UIFSM) were introduced in September 2014 and are available to all key stage 1 (4-7 years) children attending state-maintained infant and primary schools in England. The present study aimed to investigate the school-based factors, child and family socio-demographic characteristics, and parental beliefs associated with UIFSM take up in an urban community. A cross-sectional questionnaire survey was completed in October to November 2015, amongst parents whose children attended eligible schools in Leicester, England. A questionnaire about school meals was also completed by each school. Parents reported their child did not take (non-UIFSM, n = 159) or took (UIFSM, n = 517) a UIFSM on most days. The non-UIFSM group were more likely to be White-British, have a higher socio-economic status, have English as a first language, and involve their child in the decision over whether or not to take UIFSM, compared to the UIFSM group. Cluster analysis revealed that non-UIFSM parents were either concerned over quality of meals and what/how much their child ate, concerned only by what/how much their child ate or whether their child did not like the food provided. Two subsets of parents in the UIFSM group were either very positive about UIFSM or appeared to take meals because they were free. Schools used a variety of measures to increase and maintain UIFSM take up. Parents like to have control over what their child eats at school and children need to enjoy their school meals. Using a range of interventions to target subsets of parents may help local authorities, schools and caterers to increase UIFSM take up. © 2017 The British Dietetic Association Ltd.

Bottom-up effects of a no-take zone on endangered penguin demographics.

Science.gov (United States)

Sherley, Richard B; Winker, Henning; Altwegg, Res; van der Lingen, Carl D; Votier, Stephen C; Crawford, Robert J M

2015-07-01

Marine no-take zones can have positive impacts for target species and are increasingly important management tools. However, whether they indirectly benefit higher order predators remains unclear. The endangered African penguin (Spheniscus demersus) depends on commercially exploited forage fish. We examined how chick survival responded to an experimental 3-year fishery closure around Robben Island, South Africa, controlling for variation in prey biomass and fishery catches. Chick survival increased by 18% when the closure was initiated, which alone led to a predicted 27% higher population compared with continued fishing. However, the modelled population continued to decline, probably because of high adult mortality linked to poor prey availability over larger spatial scales. Our results illustrate that small no-take zones can have bottom-up benefits for highly mobile marine predators, but are only one component of holistic, ecosystem-based management regimes. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Cell adhesion and proliferation on poly(tetrafluoroethylene) with plasma-metal and plasma-metal-carbon interfaces

Science.gov (United States)

Reznickova, Alena; Kvitek, Ondrej; Kolarova, Katerina; Smejkalova, Zuzana; Svorcik, Vaclav

2017-06-01

The aim of this article is to investigate the effect of the interface between plasma activated, gold and carbon coated poly(tetrafluoroethylene) (PTFE) on in vitro adhesion and spreading of mouse fibroblasts (L929). Surface properties of pristine and modified PTFE were studied by several experimental techniques. The thickness of a deposited gold film is an increasing function of the sputtering time, conversely thickness of carbon layer decreases with increasing distance between carbon source and the substrate. Because all the used surface modification techniques take place in inert Ar plasma, oxidized degradation products are formed on the PTFE surface, which affects wettability of the polymer surface. Cytocompatibility tests indicate that on samples with Au/C interface, the cells accumulate on the part of sample with evaporated carbon. Number of L929 cells proliferated on the studied samples is comparable to tissue culture polystyrene standard.

Cytocompatibility and biocompatibility of nanostructured carbonated hydroxyapatite spheres for bone repair

Science.gov (United States)

CALASANS-MAIA, Mônica Diuana; de MELO, Bruno Raposo; ALVES, Adriana Terezinha Neves Novellino; RESENDE, Rodrigo Figueiredo de Brito; LOURO, Rafael Seabra; SARTORETTO, Suelen Cristina; GRANJEIRO, José Mauro; ALVES, Gutemberg Gomes

2015-01-01

ABSTRACT Objective The aim of this study was to investigate the in vitro and in vivo biological responses to nanostructured carbonated hydroxyapatite/calcium alginate (CHA) microspheres used for alveolar bone repair, compared to sintered hydroxyapatite (HA). Material and Methods The maxillary central incisors of 45 Wistar rats were extracted, and the dental sockets were filled with HA, CHA, and blood clot (control group) (n=5/period/group). After 7, 21 and 42 days, the samples of bone with the biomaterials were obtained for histological and histomorphometric analysis, and the plasma levels of RANKL and OPG were determined via immunoassay. Statistical analysis was performed by Two-Way ANOVA with post-hoc Tukey test at 95% level of significance. Results The CHA and HA microspheres were cytocompatible with both human and murine cells on an in vitro assay. Histological analysis showed the time-dependent increase of newly formed bone in control group characterized by an intense osteoblast activity. In HA and CHA groups, the presence of a slight granulation reaction around the spheres was observed after seven days, which was reduced by the 42nd day. A considerable amount of newly formed bone was observed surrounding the CHA spheres and the biomaterials particles at 42-day time point compared with HA. Histomorphometric analysis showed a significant increase of newly formed bone in CHA group compared with HA after 21 and 42 days from surgery, moreover, CHA showed almost 2-fold greater biosorption than HA at 42 days (two-way ANOVA, p<0.05) indicating greater biosorption. An increase in the RANKL/OPG ratio was observed in the CHA group on the 7th day. Conclusion CHA spheres were osteoconductive and presented earlier biosorption, inducing early increases in the levels of proteins involved in resorption. PMID:26814461

Cytocompatibility and biocompatibility of nanostructured carbonated hydroxyapatite spheres for bone repair

Directory of Open Access Journals (Sweden)

Mônica Diuana CALASANS-MAIA

2015-12-01

Full Text Available ABSTRACT Objective The aim of this study was to investigate the in vitro and in vivo biological responses to nanostructured carbonated hydroxyapatite/calcium alginate (CHA microspheres used for alveolar bone repair, compared to sintered hydroxyapatite (HA. Material and Methods The maxillary central incisors of 45 Wistar rats were extracted, and the dental sockets were filled with HA, CHA, and blood clot (control group (n=5/period/group. After 7, 21 and 42 days, the samples of bone with the biomaterials were obtained for histological and histomorphometric analysis, and the plasma levels of RANKL and OPG were determined via immunoassay. Statistical analysis was performed by Two-Way ANOVA with post-hoc Tukey test at 95% level of significance. Results The CHA and HA microspheres were cytocompatible with both human and murine cells on an in vitro assay. Histological analysis showed the time-dependent increase of newly formed bone in control group characterized by an intense osteoblast activity. In HA and CHA groups, the presence of a slight granulation reaction around the spheres was observed after seven days, which was reduced by the 42nd day. A considerable amount of newly formed bone was observed surrounding the CHA spheres and the biomaterials particles at 42-day time point compared with HA. Histomorphometric analysis showed a significant increase of newly formed bone in CHA group compared with HA after 21 and 42 days from surgery, moreover, CHA showed almost 2-fold greater biosorption than HA at 42 days (two-way ANOVA, p<0.05 indicating greater biosorption. An increase in the RANKL/OPG ratio was observed in the CHA group on the 7th day. Conclusion CHA spheres were osteoconductive and presented earlier biosorption, inducing early increases in the levels of proteins involved in resorption.

In vitro corrosion properties and cytocompatibility of Fe-Ga alloys as potential biodegradable metallic materials.

Science.gov (United States)

Wang, Henan; Zheng, Yang; Liu, Jinghua; Jiang, Chengbao; Li, Yan

2017-02-01

The in vitro biodegradable properties and cytocompatibility of Fe-Ga alloys including Fe 81 Ga 19 , (Fe 81 Ga 19 ) 98 B 2 and (Fe 81 Ga 19 ) 99.5 (TaC) 0.5 , and pure Fe were investigated for biomedical applications. The microstructure of the alloys was characterized using X-ray diffraction spectroscopy and optical microscopy. The results showed that A2 and D0 3 phases were detected for the three types of Fe-Ga alloys, and additional Fe 2 B and TaC phases were found in the (Fe 81 Ga 19 ) 98 B 2 and (Fe 81 Ga 19 ) 99.5 (TaC) 0.5 alloys, respectively. The corrosion rates of the Fe-Ga alloys were higher than that of pure Fe, as demonstrated by both potentiodynamic polarization measurements and immersion tests in simulated body fluid. The alloying element Ga lowered the corrosion potential of the Fe matrix and made it more susceptible to corrosion. Severe pitting corrosion developed on the surface of the Fe 81 Ga 19 alloy after the addition of ternary B or TaC due to the multi-phase microstructures. The MC3T3-E1 cells exhibited good adhesion and proliferation behavior on the surfaces of the Fe-Ga alloys after culture for 4h and 24h. Copyright © 2016 Elsevier B.V. All rights reserved.

Length-dependent corrosion behavior, Ni2+ release, cytocompatibility, and antibacterial ability of Ni-Ti-O nanopores anodically grown on biomedical NiTi alloy.

Science.gov (United States)

Hang, Ruiqiang; Liu, Yanlian; Bai, Long; Zhang, Xiangyu; Huang, Xiaobo; Jia, Husheng; Tang, Bin

2018-08-01

In the present work, nickel-titanium-oxygen nanopores with different length (0.55-114 μm) were anodically grown on nearly equiatomic nickel-titanium (NiTi) alloy. Length-dependent corrosion behavior, nickel ion (Ni 2+ ) release, cytocompatibility, and antibacterial ability were investigated by electrochemical, analytical chemistry, and biological methods. The results show constructing nanoporous structure on the NiTi alloy improve its corrosion resistance. However, the anodized samples release more Ni 2+ than that of the bare NiTi alloy, suggesting chemical dissolution of the nanopores rather than electrochemical corrosion governs the Ni 2+ release. In addition, the Ni 2+ release amount increases with nanopore length. The anodized samples show good cytocompatibility when the nanopore length is covers the one (1-11 μm) that the nanopores showing favorable antibacterial ability. Consequently, the nanopores with length in the range of 1-11 μm are promising as coatings of biomedical NiTi alloy for anti-infection, drug delivery, and other desirable applications. Copyright © 2018 Elsevier B.V. All rights reserved.

Clostridium botulinum C2 toxin--new insights into the cellular up-take of the actin-ADP-ribosylating toxin.

Science.gov (United States)

Aktories, Klaus; Barth, Holger

2004-04-01

Clostridium botulinum C2 toxin is a member of the family of binary actin-ADP-ribosylating toxins. It consists of the enzyme component C2I, and the separated binding/translocation component C2II. Proteolytically activated C2II forms heptamers and binds to a carbohydrate cell surface receptor. After attachment of C2I, the toxin complex is endocytosed to reach early endosomes. At low pH of endosomes, C2II-heptamers insert into the membrane, form pores and deliver C2I into the cytosol. Here, C2I ADP-ribosylates actin at Arg177 to block actin polymerization and to induce depolymerization of actin filaments. The mini-review describes main properties of C2 toxin and discusses new findings on the involvement of chaperones in the up-take process of the toxin.

Influence of the Microstructure and Silver Content on Degradation, Cytocompatibility, and Antibacterial Properties of Magnesium-Silver Alloys In Vitro

Directory of Open Access Journals (Sweden)

Zhidan Liu

2017-01-01

Full Text Available Implantation is a frequent procedure in orthopedic surgery, particularly in the aging population. However, it possesses the risk of infection and biofilm formation at the surgical site. This can cause unnecessary suffering to patients and burden on the healthcare system. Pure Mg, as a promising metal for biodegradable orthopedic implants, exhibits some antibacterial effects due to the alkaline pH produced during degradation. However, this antibacterial effect may not be sufficient in a dynamic environment, for example, the human body. The aim of this study was to increase the antibacterial properties under harsh and dynamic conditions by alloying silver metal with pure Mg as much as possible. Meanwhile, the Mg-Ag alloys should not show obvious cytotoxicity to human primary osteoblasts. Therefore, we studied the influence of the microstructure and the silver content on the degradation behavior, cytocompatibility, and antibacterial properties of Mg-Ag alloys in vitro. The results indicated that a higher silver content can increase the degradation rate of Mg-Ag alloys. However, the degradation rate could be reduced by eliminating the precipitates in the Mg-Ag alloys via T4 treatment. By controlling the microstructure and increasing the silver content, Mg-Ag alloys obtained good antibacterial properties in harsh and dynamic conditions but had almost equivalent cytocompatibility to human primary osteoblasts as pure Mg.

Influence of the Microstructure and Silver Content on Degradation, Cytocompatibility, and Antibacterial Properties of Magnesium-Silver Alloys In Vitro.

Science.gov (United States)

Liu, Zhidan; Schade, Ronald; Luthringer, Bérengère; Hort, Norbert; Rothe, Holger; Müller, Sören; Liefeith, Klaus; Willumeit-Römer, Regine; Feyerabend, Frank

2017-01-01

Implantation is a frequent procedure in orthopedic surgery, particularly in the aging population. However, it possesses the risk of infection and biofilm formation at the surgical site. This can cause unnecessary suffering to patients and burden on the healthcare system. Pure Mg, as a promising metal for biodegradable orthopedic implants, exhibits some antibacterial effects due to the alkaline pH produced during degradation. However, this antibacterial effect may not be sufficient in a dynamic environment, for example, the human body. The aim of this study was to increase the antibacterial properties under harsh and dynamic conditions by alloying silver metal with pure Mg as much as possible. Meanwhile, the Mg-Ag alloys should not show obvious cytotoxicity to human primary osteoblasts. Therefore, we studied the influence of the microstructure and the silver content on the degradation behavior, cytocompatibility, and antibacterial properties of Mg-Ag alloys in vitro. The results indicated that a higher silver content can increase the degradation rate of Mg-Ag alloys. However, the degradation rate could be reduced by eliminating the precipitates in the Mg-Ag alloys via T4 treatment. By controlling the microstructure and increasing the silver content, Mg-Ag alloys obtained good antibacterial properties in harsh and dynamic conditions but had almost equivalent cytocompatibility to human primary osteoblasts as pure Mg.

Scaling up ITO-Free solar cells

NARCIS (Netherlands)

Galagan, Y.O.; Coenen, E.W.C.; Zimmermann, B.; Slooff, L.H.; Verhees, W.J.H.; Veenstra, S.C.; Kroon, J.M.; Jørgensen, M.; Krebs, F.C.; Andriessen, H.A.J.M.

2014-01-01

Indium-tin-oxide-free (ITO-free) polymer solar cells with composite electrodes containing current-collecting grids and a semitransparent poly(3,4-ethylenedioxythiophene):polystyrenesulfonate) (PEDOT:PSS) conductor are demonstrated. The up-scaling of the length of the solar cell from 1 to 6 cm and

Onchocerciasis in West Africa after 2002: a challenge to take up

Directory of Open Access Journals (Sweden)

Hougard J.M.

2002-06-01

Full Text Available Initially planned for a 20 year life time, the Onchocerciasis Control Programme in West Africa (OCP will have finally continued its activities for nearly three decades (vector control alone from 1975 to 1989, then vector control and/or therapeutic treatment until 2002. Although onchocerciasis is no longer a problem of public health importance nor an obstacle to socioeconomic development in the OCP area, the control of this filariasis is not over because OCP never aimed at eradication, neither of the parasite (Onchocerca volvulus, nor of its vector (Simulium damnosum s.l.. In 2003, the eleven Participating countries of OCP will take over the responsibility of carrying out the residual activities of monitoring and the control of this disease. This mission is of great importance because any recrudescence of the transmission could lead in the long run to the reappearance of the clinical signs of onchocerciasis, if not its most serious manifestations. For epidemiological and operational reasons, and given the disparity in national health policies and infrastructures, the capacities of the countries to take over the residual activities of monitoring and control of onchocerciasis are very unequal. Indeed, the interventions to be carried out are very different from one country to another and the process of integrating the residual activities into the national health systems is not taking place at the same pace. This inequality among the countries vis-a-vis the challenges to be met does not, however, prejudge the epidemiological situation after 2002 whose evolution will also depend on the effectiveness of the provisions made before that date by OCP, then after 2002, by the Regional Office for Africa of the World Health Organization which is currently setting up a sub-regional multidisease surveillance centre.

In vitro corrosion and cytocompatibility properties of nano-whisker hydroxyapatite coating on magnesium alloy for bone tissue engineering applications.

Science.gov (United States)

Yang, Huawei; Yan, Xueyu; Ling, Min; Xiong, Zuquan; Ou, Caiwen; Lu, Wei

2015-03-17

We report here the successful fabrication of nano-whisker hydroxyapatite (nHA) coatings on Mg alloy by using a simple one-step hydrothermal process in aqueous solution. The nHA coating shows uniform structure and high crystallinity. Results indicate that nHA coating is promising for improving the in vitro corrosion and cytocompatibility properties of Mg-based implants and devices for bone tissue engineering. In addition, the simple hydrothermal deposition method used in the current study is also applicable to substrates with complex shapes or surface geometries.

Nanostructured titanium–silver coatings with good antibacterial activity and cytocompatibility fabricated by one-step magnetron sputtering

Energy Technology Data Exchange (ETDEWEB)

Bai, Long [Research Institute of Surface Engineering, Taiyuan University of Technology, Taiyuan (China); Hang, Ruiqiang, E-mail: hangruiqiang@tyut.edu.cn [Research Institute of Surface Engineering, Taiyuan University of Technology, Taiyuan (China); Gao, Ang [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China); Zhang, Xiangyu; Huang, Xiaobo; Wang, Yueyue; Tang, Bin [Research Institute of Surface Engineering, Taiyuan University of Technology, Taiyuan (China); Zhao, Lingzhou, E-mail: zhaolingzhou1983@hotmail.com [State Key Laboratory of Military Stomatology, Department of Periodontology, School of Stomatology, The Fourth Military Medical University, Xi’an (China); Chu, Paul K. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China)

2015-11-15

Graphical abstract: - Highlights: • We fabricate Ti–Ag coatings with different Ag contents and surface morphologies. • The Ti–Ag coatings possess long-term antibacterial ability. • Increased Ag contents in the coatings leads to enhanced osteoblast functions. - Abstract: Bacterial infection and loosing are serious complications for biomedical implants in the orthopedic, dental, and other biomedical fields and the ideal implants should combine good antibacterial ability and bioactivity. In this study, nanostructured titanium–silver (Ti–Ag) coatings with different Ag contents (1.2 to 21.6 at%) are prepared on Ti substrates by magnetron sputtering. As the Ag concentration is increased, the coatings change from having dense columnar crystals to sparse ones and eventually no columnar structure. The Ti–Ag coatings can effectively kill Staphylococcus aureus during the first few days and remain moderately antibacterial after immersion for 75 days. Compared to pure Ti, the Ti–Ag coatings show good cytocompatibility as indicated by good osteoblast adhesion, proliferation, intracellular total protein synthesis, and alkaline phosphatase (ALP) activity. In addition, cell spreading, collagen secretion, and extracellular matrix mineralization are promoted on the coatings with the proper Ag contents due to the nanostructured morphological features. Our results indicate that favorable antibacterial activity and osseointegration ability can be simultaneously achieved by regulating the Ag contents in Ti–Ag coatings.

Life Insurance Take-Up Rate Influencing Factors Comparison between Malaysia and Japan

Directory of Open Access Journals (Sweden)

Silvana Kardinar Wijayanti

2016-08-01

Full Text Available This study will investigate the factors that influence take-up rates within the Malaysian Life Insurance industry to discover potential opportunities and limitations. For comparative purposes, the study is modelled on Power (2013 who examined four factors affecting customer satisfaction in life insurance in Japan (product, price, customer services and procedures and documentation. This study is exploratory in nature using both secondary research and primary data from questionnaires. The main finding was “Product offerings” being the most significant variation, both an opportunity and limitation, due to the relative maturity, experience and changing trends within the insurance market of Japan, conversely growth, infancy and different dynamics in Malaysia.

Cell proliferation, viability, and in vitro differentiation of equine mesenchymal stem cells seeded on bacterial cellulose hydrogel scaffolds

International Nuclear Information System (INIS)

Favi, Pelagie M.; Benson, Roberto S.; Neilsen, Nancy R.; Hammonds, Ryan L.; Bates, Cassandra C.; Stephens, Christopher P.; Dhar, Madhu S.

2013-01-01

The culture of multipotent mesenchymal stem cells on natural biopolymers holds great promise for treatments of connective tissue disorders such as osteoarthritis. The safety and performance of such therapies relies on the systematic in vitro evaluation of the developed stem cell-biomaterial constructs prior to in vivo implantation. This study evaluates bacterial cellulose (BC), a biocompatible natural polymer, as a scaffold for equine-derived bone marrow mesenchymal stem cells (EqMSCs) for application in bone and cartilage tissue engineering. An equine model was chosen due to similarities in size, load and types of joint injuries suffered by horses and humans. Lyophilized and critical point dried BC hydrogel scaffolds were characterized using scanning electron microscopy (SEM) to confirm nanostructure morphology which demonstrated that critical point drying induces fibre bundling unlike lyophilisation. EqMSCs positively expressed the undifferentiated pluripotent mesenchymal stem cell surface markers CD44 and CD90. The BC scaffolds were shown to be cytocompatible, supporting cellular adhesion and proliferation, and allowed for osteogenic and chondrogenic differentiation of EqMSCs. The cells seeded on the BC hydrogel were shown to be viable and metabolically active. These findings demonstrate that the combination of a BC hydrogel and EqMSCs are promising constructs for musculoskeletal tissue engineering applications. - Highlights: ► Critical point drying induces fibre bundling unlike lyophilisation. ► Cells positively expressed undifferentiated pluripotent stem cell markers. ► BCs were cytocompatible, supported cell adhesion, proliferation and differentiation ► Cells seeded on BC scaffolds were viable and metabolically active. ► Findings demonstrate that BC and EqMSCs are promising tissue engineered constructs

Cell proliferation, viability, and in vitro differentiation of equine mesenchymal stem cells seeded on bacterial cellulose hydrogel scaffolds

Energy Technology Data Exchange (ETDEWEB)

Favi, Pelagie M.; Benson, Roberto S. [Department of Materials Science and Engineering, College of Engineering, University of Tennessee, Knoxville, TN 37996 (United States); Neilsen, Nancy R. [Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996 (United States); Hammonds, Ryan L. [Department of Materials Science and Engineering, College of Engineering, University of Tennessee, Knoxville, TN 37996 (United States); Bates, Cassandra C. [Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996 (United States); Stephens, Christopher P. [Department of Surgery, Graduate School of Medicine, University of Tennessee, Knoxville, TN 37996 (United States); Center for Materials Processing, University of Tennessee, Knoxville, TN 37996 (United States); Dhar, Madhu S., E-mail: mdhar@utk.edu [Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996 (United States)

2013-05-01

The culture of multipotent mesenchymal stem cells on natural biopolymers holds great promise for treatments of connective tissue disorders such as osteoarthritis. The safety and performance of such therapies relies on the systematic in vitro evaluation of the developed stem cell-biomaterial constructs prior to in vivo implantation. This study evaluates bacterial cellulose (BC), a biocompatible natural polymer, as a scaffold for equine-derived bone marrow mesenchymal stem cells (EqMSCs) for application in bone and cartilage tissue engineering. An equine model was chosen due to similarities in size, load and types of joint injuries suffered by horses and humans. Lyophilized and critical point dried BC hydrogel scaffolds were characterized using scanning electron microscopy (SEM) to confirm nanostructure morphology which demonstrated that critical point drying induces fibre bundling unlike lyophilisation. EqMSCs positively expressed the undifferentiated pluripotent mesenchymal stem cell surface markers CD44 and CD90. The BC scaffolds were shown to be cytocompatible, supporting cellular adhesion and proliferation, and allowed for osteogenic and chondrogenic differentiation of EqMSCs. The cells seeded on the BC hydrogel were shown to be viable and metabolically active. These findings demonstrate that the combination of a BC hydrogel and EqMSCs are promising constructs for musculoskeletal tissue engineering applications. - Highlights: ► Critical point drying induces fibre bundling unlike lyophilisation. ► Cells positively expressed undifferentiated pluripotent stem cell markers. ► BCs were cytocompatible, supported cell adhesion, proliferation and differentiation ► Cells seeded on BC scaffolds were viable and metabolically active. ► Findings demonstrate that BC and EqMSCs are promising tissue engineered constructs.

PLGA/DPPC/trimethylchitosan spray-dried microparticles for the nasal delivery of ropinirole hydrochloride: in vitro, ex vivo and cytocompatibility assessment

Energy Technology Data Exchange (ETDEWEB)

Karavasili, Christina [Laboratory of Pharmaceutical Technology, Department of Pharmacy, Aristotle University of Thessaloniki, 54124 (Greece); Bouropoulos, Nikolaos [Department of Materials Science, University of Patras, 26504 Rio, Patras (Greece); Foundation for Research and Technology, Hellas-Institute of Chemical Engineering and High Temperature, P.O. Box 1414, 26504 Patras (Greece); Sygellou, Lamprini [Foundation for Research and Technology, Hellas-Institute of Chemical Engineering and High Temperature, P.O. Box 1414, 26504 Patras (Greece); Amanatiadou, Elsa P.; Vizirianakis, Ioannis S. [Laboratory of Pharmacology, Department of Pharmaceutical Sciences, Aristotle University of Thessaloniki, GR-54124 Thessaloniki (Greece); Fatouros, Dimitrios G., E-mail: dfatouro@pharm.auth.gr [Laboratory of Pharmaceutical Technology, Department of Pharmacy, Aristotle University of Thessaloniki, 54124 (Greece)

2016-02-01

In the present study we investigated polymer-lipid microparticles loaded with ropinirole hydrochloride (RH) for nasal delivery. RH microparticles were further evaluated by means of scanning electron microscopy (SEM), ζ-potential measurements, Fourier-transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and x-ray diffraction (XRD). In vitro release studies were performed in simulated nasal electrolyte solution (SNES) pH 5.5 at 35 °C. Ex vivo permeation studies were conducted across sheep nasal mucosa. Cytocompatibility was tested in cultured human airway epithelial cells (Calu-3). SEM studies revealed spheroid microparticles in the range of 2.09 μm to 2.41 μm. The presence of trimethylchitosan (TMC) induced a slight shift towards less negative ζ-potential values. Surface chemistry (XPS) revealed the presence of dipalmitoylphospatidylcholine (DPPC) and poly(lactic-co-glycolic acid) (PLGA) onto microparticles' surface, further corroborating the FT-IR and XRD findings. In vitro release studies showed that the microparticle composition can partly modulate the release of RH. Ex vivo studies demonstrated a 2.35-folded enhancement of RH permeation when RH was co-formulated with TMC of low molecular weight, compared to the control. All formulations tested were found to be non-toxic to cells. The results suggest that polymer-lipid microparticles may be a promising carrier for the nasal delivery of RH. - Highlights: • Development of microparticles comprising PLGA/DPPC/TMC for nasal drug delivery. • Physicochemical characterization showed that DPPC dominated microparticles' surface. • Microparticles enhanced permeation of ropinirole across sheep nasal epithelium. • The cytotoxicity assay with Calu-3 cells demonstrated satisfactory cell viability.

PLGA/DPPC/trimethylchitosan spray-dried microparticles for the nasal delivery of ropinirole hydrochloride: in vitro, ex vivo and cytocompatibility assessment

International Nuclear Information System (INIS)

Karavasili, Christina; Bouropoulos, Nikolaos; Sygellou, Lamprini; Amanatiadou, Elsa P.; Vizirianakis, Ioannis S.; Fatouros, Dimitrios G.

2016-01-01

In the present study we investigated polymer-lipid microparticles loaded with ropinirole hydrochloride (RH) for nasal delivery. RH microparticles were further evaluated by means of scanning electron microscopy (SEM), ζ-potential measurements, Fourier-transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and x-ray diffraction (XRD). In vitro release studies were performed in simulated nasal electrolyte solution (SNES) pH 5.5 at 35 °C. Ex vivo permeation studies were conducted across sheep nasal mucosa. Cytocompatibility was tested in cultured human airway epithelial cells (Calu-3). SEM studies revealed spheroid microparticles in the range of 2.09 μm to 2.41 μm. The presence of trimethylchitosan (TMC) induced a slight shift towards less negative ζ-potential values. Surface chemistry (XPS) revealed the presence of dipalmitoylphospatidylcholine (DPPC) and poly(lactic-co-glycolic acid) (PLGA) onto microparticles' surface, further corroborating the FT-IR and XRD findings. In vitro release studies showed that the microparticle composition can partly modulate the release of RH. Ex vivo studies demonstrated a 2.35-folded enhancement of RH permeation when RH was co-formulated with TMC of low molecular weight, compared to the control. All formulations tested were found to be non-toxic to cells. The results suggest that polymer-lipid microparticles may be a promising carrier for the nasal delivery of RH. - Highlights: • Development of microparticles comprising PLGA/DPPC/TMC for nasal drug delivery. • Physicochemical characterization showed that DPPC dominated microparticles' surface. • Microparticles enhanced permeation of ropinirole across sheep nasal epithelium. • The cytotoxicity assay with Calu-3 cells demonstrated satisfactory cell viability.

Chemical sporulation and germination: cytoprotective nanocoating of individual mammalian cells with a degradable tannic acid-FeIII complex

Science.gov (United States)

Lee, Juno; Cho, Hyeoncheol; Choi, Jinsu; Kim, Doyeon; Hong, Daewha; Park, Ji Hun; Yang, Sung Ho; Choi, Insung S.

2015-11-01

Individual mammalian cells were coated with cytoprotective and degradable films by cytocompatible processes maintaining the cell viability. Three types of mammalian cells (HeLa, NIH 3T3, and Jurkat cells) were coated with a metal-organic complex of tannic acid (TA) and ferric ion, and the TA-FeIII nanocoat effectively protected the coated mammalian cells against UV-C irradiation and a toxic compound. More importantly, the cell proliferation was controlled by programmed formation and degradation of the TA-FeIII nanocoat, mimicking the sporulation and germination processes found in nature.Individual mammalian cells were coated with cytoprotective and degradable films by cytocompatible processes maintaining the cell viability. Three types of mammalian cells (HeLa, NIH 3T3, and Jurkat cells) were coated with a metal-organic complex of tannic acid (TA) and ferric ion, and the TA-FeIII nanocoat effectively protected the coated mammalian cells against UV-C irradiation and a toxic compound. More importantly, the cell proliferation was controlled by programmed formation and degradation of the TA-FeIII nanocoat, mimicking the sporulation and germination processes found in nature. Electronic supplementary information (ESI) available: Experimental details, LSCM images, and SEM and TEM images. See DOI: 10.1039/c5nr05573c

In Vitro Corrosion and Cytocompatibility Properties of Nano-Whisker Hydroxyapatite Coating on Magnesium Alloy for Bone Tissue Engineering Applications

Directory of Open Access Journals (Sweden)

Huawei Yang

2015-03-01

Full Text Available We report here the successful fabrication of nano-whisker hydroxyapatite (nHA coatings on Mg alloy by using a simple one-step hydrothermal process in aqueous solution. The nHA coating shows uniform structure and high crystallinity. Results indicate that nHA coating is promising for improving the in vitro corrosion and cytocompatibility properties of Mg-based implants and devices for bone tissue engineering. In addition, the simple hydrothermal deposition method used in the current study is also applicable to substrates with complex shapes or surface geometries.

Enhanced mechanical properties and cytocompatibility of electrospun poly(L-lactide) composite fiber membranes assisted by polydopamine-coated halloysite nanotubes

Energy Technology Data Exchange (ETDEWEB)

Luo, Chuang; Zou, Ziping [Biomaterial Research Laboratory, Department of Material Science and Engineering, College of Science and Engineering, Jinan University, Guangzhou 510632 (China); Luo, Binghong, E-mail: tluobh@jnu.edu.cn [Biomaterial Research Laboratory, Department of Material Science and Engineering, College of Science and Engineering, Jinan University, Guangzhou 510632 (China); Engineering Research Center of Artificial Organs and Materials, Ministry of Education, Guangzhou 510632 (China); Wen, Wei [Biomaterial Research Laboratory, Department of Material Science and Engineering, College of Science and Engineering, Jinan University, Guangzhou 510632 (China); Engineering Research Center of Artificial Organs and Materials, Ministry of Education, Guangzhou 510632 (China); Li, Huihua [Biomaterial Research Laboratory, Department of Material Science and Engineering, College of Science and Engineering, Jinan University, Guangzhou 510632 (China); Liu, Mingxian [Biomaterial Research Laboratory, Department of Material Science and Engineering, College of Science and Engineering, Jinan University, Guangzhou 510632 (China); Engineering Research Center of Artificial Organs and Materials, Ministry of Education, Guangzhou 510632 (China); Zhou, Changren, E-mail: tcrz9@jnu.edu.cn [Biomaterial Research Laboratory, Department of Material Science and Engineering, College of Science and Engineering, Jinan University, Guangzhou 510632 (China); Engineering Research Center of Artificial Organs and Materials, Ministry of Education, Guangzhou 510632 (China)

2016-04-30

Graphical abstract: - Highlights: • D-HNTs was prepared by a facile approach based on the self-polymerization of DOPA. • The D-HNTs can disperse more uniformly in PLLA matrix than untreated HNTs. • The interfacial adhesion between D-HNTs and PLLA matrix was obviously improved. • D-HNTs/PLLA fiber membrane has better tensile properties compared with HNTs/PLLA. • The D-HNTs/PLLA fiber membrane is favorable to cell adhesion and proliferation. - Abstract: To improve the dispersion and interfacial interaction between halloysite nanotubes (HNTs) and poly(L-lactide) (PLLA) matrix, and hence to increase the mechanical properties and cytocompatibility of the HNTs/PLLA composite, a facile approach was developed to prepare polydopamine-coated HNTs (D-HNTs) by the self-polymerization of dopamine (DOPA), and then HNTs and D-HNTs were further introduced into PLLA matrix to fabricate HNTs/PLLA and D-HNTs/PLLA fiber membranes based on electrospinning technique. The successful immobilization of the polydopamine (PDOPA) coating on the surfaces of HNTs was confirmed, and such PDOPA coating played an important role in improving the interfacial interaction between the nanotubes and PLLA matrix. The D-HNTs were dispersed in the matrix more uniformly than untreated HNTs, and relative smooth and uniform fiber were obtained for the D-HNTs/PLLA fiber membrane. As a result, the tensile strength and modulus of the D-HNTs/PLLA fiber membrane were obviously superior to those of the HNTs/PLLA fiber membrane. Cell culture results revealed that D-HNTs/PLLA fiber membrane was more effectively to promote MC3T3-E1 cells adhesion and proliferation than neat PLLA and HNTs/PLLA fiber membrane.

Enhanced mechanical properties and cytocompatibility of electrospun poly(L-lactide) composite fiber membranes assisted by polydopamine-coated halloysite nanotubes

International Nuclear Information System (INIS)

Luo, Chuang; Zou, Ziping; Luo, Binghong; Wen, Wei; Li, Huihua; Liu, Mingxian; Zhou, Changren

2016-01-01

Graphical abstract: - Highlights: • D-HNTs was prepared by a facile approach based on the self-polymerization of DOPA. • The D-HNTs can disperse more uniformly in PLLA matrix than untreated HNTs. • The interfacial adhesion between D-HNTs and PLLA matrix was obviously improved. • D-HNTs/PLLA fiber membrane has better tensile properties compared with HNTs/PLLA. • The D-HNTs/PLLA fiber membrane is favorable to cell adhesion and proliferation. - Abstract: To improve the dispersion and interfacial interaction between halloysite nanotubes (HNTs) and poly(L-lactide) (PLLA) matrix, and hence to increase the mechanical properties and cytocompatibility of the HNTs/PLLA composite, a facile approach was developed to prepare polydopamine-coated HNTs (D-HNTs) by the self-polymerization of dopamine (DOPA), and then HNTs and D-HNTs were further introduced into PLLA matrix to fabricate HNTs/PLLA and D-HNTs/PLLA fiber membranes based on electrospinning technique. The successful immobilization of the polydopamine (PDOPA) coating on the surfaces of HNTs was confirmed, and such PDOPA coating played an important role in improving the interfacial interaction between the nanotubes and PLLA matrix. The D-HNTs were dispersed in the matrix more uniformly than untreated HNTs, and relative smooth and uniform fiber were obtained for the D-HNTs/PLLA fiber membrane. As a result, the tensile strength and modulus of the D-HNTs/PLLA fiber membrane were obviously superior to those of the HNTs/PLLA fiber membrane. Cell culture results revealed that D-HNTs/PLLA fiber membrane was more effectively to promote MC3T3-E1 cells adhesion and proliferation than neat PLLA and HNTs/PLLA fiber membrane.

Scaling Up ITO-free solar cells

DEFF Research Database (Denmark)

Galagan, Yulia; Coenen, Erica W. C.; Zimmermann, Birger

2014-01-01

Indium-tin-oxide-free (ITO-free) polymer solar cells with composite electrodes containing current-collecting grids and a semitransparent poly(3,4-ethylenedioxythiophene):polystyrenesulfonate) (PEDOT:PSS) conductor are demonstrated. The up-scaling of the length of the solar cell from 1 to 6 cm...... resistances. The performance of ITO-free organic solar cells with different dimensions and different electrode resistances are evaluated for different light intensities. The current generation and electric potential distribution are found to not be uniformly distributed in large-area devices at simulated 1...

Solar Cells Light Up Prison Cells on 'The Rock' | News | NREL

Science.gov (United States)

taking up a good deal of the island. The 1,300 solar panels on the Cellhouse building are a dark blue panels on the rooftop of the Cellhouse building. Courtesy of the National Park Service "Machine Gun to 1,300 solar panels, powering lights and appliances that for three-quarters of a century were

Development of Composite Poly(Lactide-co-Glycolide)- Nanodiamond Scaffolds for Bone Cell Growth

Czech Academy of Sciences Publication Activity Database

Brady, M.A.; Renzing, A.; Douglas, T.E.L.; Liu, Q.; Wille, S.; Pařízek, Martin; Bačáková, Lucie; Kromka, Alexander; Jarošová, Markéta; Godier, G.; Warnke, P. H.

2015-01-01

Roč. 15, č. 2 (2015), s. 1060-1069 ISSN 1533-4880 R&D Projects: GA ČR(CZ) GBP108/12/G108 Institutional support: RVO:67985823 ; RVO:68378271 Keywords : diamond nanoparticles * PLGA * human MSC * nanofibres * cytocompatibility * cell growth Subject RIV: JJ - Other Materials Impact factor: 1.338, year: 2015

A One-Dimensional Particle-in-Cell Model of Plasma Build-Up in Vacuum Arcs

CERN Document Server

Timko, H; Kovermann, J; Taborelli, M; Nordlund, K; Descoeudres, A; Schneider, R; Calatroni, S; Matyash, K; Wuensch, W; Hansen, A; Grudiev, A

2011-01-01

Understanding the mechanism of plasma build-up in vacuum arcs is essential in many fields of physics. A one-dimensional particle-in-cell computer simulation model is presented, which models the plasma developing from a field emitter tip under electrical breakdown conditions, taking into account the relevant physical phenomena. As a starting point, only an external electric field and an initial enhancement factor of the tip are assumed. General requirements for plasma formation have been identified and formulated in terms of the initial local field and a critical neutral density. The dependence of plasma build-up on tip melting current, the evaporation rate of neutrals and external circuit time constant has been investigated for copper and simulations imply that arcing involves melting currents around 0.5-1 A/mu m(2),evaporation of neutrals to electron field emission ratios in the regime 0.01 - 0.05, plasma build-up timescales in the order of similar to 1 - 10 ns and two different regimes depending on initial ...

Effect of barium-coated halloysite nanotube addition on the cytocompatibility, mechanical and contrast properties of poly(methyl methacrylate cement

Directory of Open Access Journals (Sweden)

Jammalamadaka U

2017-06-01

Full Text Available Uday Jammalamadaka,1 Karthik Tappa,1 Jeffery A Weisman,1 James Connor Nicholson,2 David K Mills1,3 1Center for Biomedical Engineering and Rehabilitation Science, 2Nanosystems Engineering, 3The School of Biological Sciences, Louisiana Tech University, Ruston, LA, USA Abstract: Halloysite nanotubes (HNTs were investigated as a platform for tunable nanoparticle composition and enhanced opacity in poly(methyl methacrylate (PMMA bone cement. Halloysite has been widely used to increase the mechanical properties of various polymer matrices, in stark contrast to other fillers such as barium sulfate that provide opacity but also decrease mechanical strength. The present work describes a dry deposition method for successively fabricating barium sulfate nanoparticles onto the exterior surface of HNTs. A sintering process was used to coat the HNTs in barium sulfate. Barium sulfate-coated HNTs were then added to PMMA bone cement and the samples were tested for mechanical strength and tailored opacity correlated with the fabrication ratio and the amount of barium sulfate-coated HNTs added. The potential cytotoxic effect of barium-coated HNTs in PMMA cement was also tested on osteosarcoma cells. Barium-coated HNTs were found to be completely cytocompatible, and cell proliferation was not inhibited after exposure to the barium-coated HNTs embedded in PMMA cement. We demonstrate a simple method for the creation of barium-coated nanoparticles that imparted improved contrast and material properties to native PMMA. An easy and efficient method for coating clay nanotubes offers the potential for enhanced imaging by radiologists or orthopedic surgeons. Keywords: barium, bone cement, halloysite, imaging, PMMA, sintering

Administrative Circular No. 30 (Rev. 3) - “Financial benefits on taking up appointment and on termination of contract”

CERN Multimedia

2013-01-01

Administrative Circular No. 30 (Rev. 3) entitled “Financial benefits on taking up appointment and on termination of contract”, approved by the Director-General following discussion at the Standing Concertation Committee meeting of 27 June 2013 and entering into force on 1 August 2013, is available on the intranet site of the Human Resources Department (see here).   Administrative Circular No. 30 (Rev. 3) is applicable to all members of the personnel. It cancels and replaces Administrative Circular No. 30 (Rev. 2/Corr.) entitled "Financial benefits on taking up appointment and on termination of contract” of September 2009. This circular was revised in order to implement the modifications introduced into the Staff Rules and Regulations in January 2013 relating to the introduction of the status of Associate Member States and new categories of associated members of the personnel. In particular, the notion of “Member State” in Annexe II (&a...

Radiation Effect on Secondary Cancerization by Tumour Cell Grafts. Take of Irradiated Tumour Cells in Irradiated and Non-Irradiated Animals

Energy Technology Data Exchange (ETDEWEB)

Costachel, O.; Sandru, Gh.; Kitzulescu, I. [Oncological Institute, Bucharest (Romania)

1969-11-15

This study was designed to determine the ability of haemocytoblastoma, SME and Jensen tumours, which had been irradiated in vitro, to take in C{sub 57}BL/6 mice or Wistar rats that were whole-body irradiated at 0.4 kR and 0.6 kR respectively. It was found-that the take of tumour cell grafts irradiated in vitro increased in whole-body irradiated mice and rats but not in non-irradiated ones. When Wistar rats, that had been whole-body irradiated with 0.7 and 0.8 kR 1 - 7 months earlier and survived after treatment, were grafted with Jensen tumour cells irradiated in vitro with 3 kR they were found to develop tumours and lung metastases (in contrast to non-irradiated rats). A cross resistance against non-irradiated Jensen tumour cells was obtained in non- irradiated Wistar rats by grafting irradiated Jensen tumour cells. Chromosomal analysis showed two supplementary giant markers in the Jensen tumour cells that had been irradiated in vitro before grafting. (author)

Physical characteristics, antimicrobial and odontogenesis potentials of calcium silicate cement containing hinokitiol

Energy Technology Data Exchange (ETDEWEB)

Huang, Ming-Hsien [Institute of Oral Science, Chung Shan Medical University, Taichung City, Taiwan (China); Shen, Yu-Fang; Hsu, Tuan-Ti [3D Printing Medical Research Center, China Medical University Hospital, China Medical University, Taichung City, Taiwan (China); Huang, Tsui-Hsien [School of Dentistry, Chung Shan Medical University, Taichung City, Taiwan (China); Department of Stomatology, Chung Shan Medical University Hospital, Taichung City, Taiwan (China); Shie, Ming-You, E-mail: eviltacasi@gmail.com [3D Printing Medical Research Center, China Medical University Hospital, China Medical University, Taichung City, Taiwan (China)

2016-08-01

Hinokitiol is a natural material and it has antibacterial and anti-inflammatory effects. The purpose of this study was to evaluate the material characterization, cell viability, antibacterial and anti-inflammatory abilities of the hinokitiol-modified calcium silicate (CS) cement as a root end filling material. The setting times, diametral tensile strength (DTS) values and XRD patterns of CS cements with 0–10 mM hinokitiol were examined. Then, the antibacterial effect and the expression levels of cyclooxygenase 2 (COX-2) and interleukin-1 (IL-1) of the hinokitiol-modified CS cements were evaluated. Furthermore, the cytocompatibility, the expression levels of the markers of odontoblastic differentiation, mineralized nodule formation and calcium deposition of human dental pulp cells (hDPCs) cultured on hinokitiol-modified CS cements were determined. The hinokitiol-modified CS cements had better antibacterial and anti-inflammatory abilities and cytocompatibility than non-modified CS cements. Otherwise, the hinokitiol-modified CS cements had suitable setting times and better odontoblastic potential of hDPCs. Previous report pointed out that the root-end filling materials may induce inflammatory cytokines reaction. In our study, hinokitiol-modified CS cements not only inhibited the expression level of inflammatory cytokines, but also had better cytocompatibility, antimicrobial properties and active ability of odontoblastic differentiation of hDPCs. Therefore, the hinokitiol-modified CS cement may be a potential root end filling material for clinic. - Highlights: • The hinokitiol-modified CS up-regulation of odontogenic of hDPCs. • Promoted proliferation of hDPCs on hinokitiol-modified CS. • The hinokitiol-modified CS cements not only inhibited the expression level of inflammatory cytokines, but also had better cytocompatibility. • The hinokitiol-modified CS up-regulation of odontogenic of hPDLs.

Physical characteristics, antimicrobial and odontogenesis potentials of calcium silicate cement containing hinokitiol

International Nuclear Information System (INIS)

Huang, Ming-Hsien; Shen, Yu-Fang; Hsu, Tuan-Ti; Huang, Tsui-Hsien; Shie, Ming-You

2016-01-01

Hinokitiol is a natural material and it has antibacterial and anti-inflammatory effects. The purpose of this study was to evaluate the material characterization, cell viability, antibacterial and anti-inflammatory abilities of the hinokitiol-modified calcium silicate (CS) cement as a root end filling material. The setting times, diametral tensile strength (DTS) values and XRD patterns of CS cements with 0–10 mM hinokitiol were examined. Then, the antibacterial effect and the expression levels of cyclooxygenase 2 (COX-2) and interleukin-1 (IL-1) of the hinokitiol-modified CS cements were evaluated. Furthermore, the cytocompatibility, the expression levels of the markers of odontoblastic differentiation, mineralized nodule formation and calcium deposition of human dental pulp cells (hDPCs) cultured on hinokitiol-modified CS cements were determined. The hinokitiol-modified CS cements had better antibacterial and anti-inflammatory abilities and cytocompatibility than non-modified CS cements. Otherwise, the hinokitiol-modified CS cements had suitable setting times and better odontoblastic potential of hDPCs. Previous report pointed out that the root-end filling materials may induce inflammatory cytokines reaction. In our study, hinokitiol-modified CS cements not only inhibited the expression level of inflammatory cytokines, but also had better cytocompatibility, antimicrobial properties and active ability of odontoblastic differentiation of hDPCs. Therefore, the hinokitiol-modified CS cement may be a potential root end filling material for clinic. - Highlights: • The hinokitiol-modified CS up-regulation of odontogenic of hDPCs. • Promoted proliferation of hDPCs on hinokitiol-modified CS. • The hinokitiol-modified CS cements not only inhibited the expression level of inflammatory cytokines, but also had better cytocompatibility. • The hinokitiol-modified CS up-regulation of odontogenic of hPDLs.

The preparation, cytocompatibility and antimicrobial property of micro/nano structural titanium loading alginate and antimicrobial peptide

Science.gov (United States)

Liu, Zhiyuan; Zhong, Mou; Sun, Yuhua; Chen, Junhong; Feng, Bo

2018-03-01

Titanium with hybrid microporous/nanotubes (TMNT) structure on its surface was fabricated by acid etching and subsequently anodization at different voltages. Bovine lactoferricin, a kind of antimicrobial peptide, and sodium alginate (NaAlg) were loaded onto titanium surface through layer by layer assembly. The drug release, cytocompatibility and antimicrobial property against S.aureus and E.coil were studied by release experiment, osteoblast and bacterial cultures. Results indicated that samples with nanotubes of bigger diameter carried more drugs and had better biocompatibility, and drug-loaded samples acquired better biocompatibility compared with drug-free samples. Furthermore, the drug-loaded samples exhibited good initial antimicrobial property, but weak long-term antimicrobial property. Therefore, drug-loaded titanium with micro/nano structure, especially, of big diameter nanotubes, could be a promise material for medical implants, such as internal/external fixation devices.

Pioneering renewable energy options: Thailand takes up the challenge

Energy Technology Data Exchange (ETDEWEB)

NONE

2013-07-15

Thailand’s support policies for renewable energy (RE) in the power sector have allowed individual small projects to add up to something substantial, attracting more investment and leading to faster growth in the sector than in most other Asian nations. Thai energy policy is complex, and the development of RE has not been without controversy. While this paper provides some elements of the context, it cannot cover all aspects of Thai energy policy. Instead it focuses on identifying factors that can explain the relative success of Thai policies and highlights some lessons for future development. Key messages include: Thailand was among the first countries in Asia to introduce incentive policies for the generation of electricity from renewable energy (RE) sources, leading to rapid growth, particularly in solar power; programmes for small and very small power producers created predictable conditions for RE investors to sell electricity to the grid. The 'Adder', a feed-in premium, guarantees higher rates for RE, making the investments profitable. Thailand also regularly updates technical regulations, provides preferential financing, and invests in research and training; civil society involvement strengthened and improved RE policies. In Thailand, outside expertise and links to international networks brought in by civil society experts were crucial for the design and approval of the incentive measures; and, the Thai Government is now adapting its policies to take account of recent technological progress and market growth. It is considering a sophisticated feed-in tariff to better control costs, while continuing to offer an enabling environment for RE investments.

Physico-chemical properties of PDMS surfaces suitable as substrates for cell cultures

Energy Technology Data Exchange (ETDEWEB)

Raczkowska, Joanna, E-mail: joanna.raczkowska@uj.edu.pl [The Marian Smoluchowski Institute of Physics, Jagiellonian University, Łojasiewicza 11, 30-428 Kraków (Poland); Prauzner-Bechcicki, Szymon [Institute of Nuclear Physics Polish Academy of Sciences, Radzikowskiego 152, 31-342 Kraków (Poland); Lukes, Jaroslav; Sepitka, Josef [Czech Technical University in Prague, Faculty of Mechanical Engineering, Technicka 4, 16607 Prague (Czech Republic); Bernasik, Andrzej [Faculty of Physics and Applied Computer Science, AGH - University of Science and Technology, Reymonta 19, 30-049 Kraków (Poland); Awsiuk, Kamil [The Marian Smoluchowski Institute of Physics, Jagiellonian University, Łojasiewicza 11, 30-428 Kraków (Poland); Paluszkiewicz, Czesława; Pabijan, Joanna; Lekka, Małgorzata [Institute of Nuclear Physics Polish Academy of Sciences, Radzikowskiego 152, 31-342 Kraków (Poland); Budkowski, Andrzej [The Marian Smoluchowski Institute of Physics, Jagiellonian University, Łojasiewicza 11, 30-428 Kraków (Poland)

2016-12-15

Highlights: • Series of PDMS substrates with monotonically tuned elasticity were produced. • Method to estimate PDMS stiffness based on AFM force-distance curves was shown. • No change in surface properties of PDMS other than elasticity was demonstrated. • MTT performed for cancer cells showed impact of PDMS elasticity on cells behavior. - Abstract: Elastic properties of the substrate have profound effect on adhesion and proliferation of cells. Here, we introduce a method to produce polydimethylsiloxane (PDMS) substrates with stiffness tuned monotonically from 1.67 to 0.24 MPa, by the time of UV irradiation adjusted up to 5 h. The Young’s modulus (determined by using nanoindenter) scales linearly with stiffness calculated using AFM-based force spectroscopy data. Such a relation enables the determination of the Young modulus from AFM force – distance curves also when the Herz model is not applicable. Our findings demonstrate that surface properties of PDMS substrates are not affected by the applied methodology of tuning substrate elasticity. Finally, the colorimetric proliferation assay (MTT) carried out for non-malignant (HCV29) and cancerous (T24) bladder cancer cells depicted a significant contribution of PDMS substrate elasticity to the behavior of cells. The softer PDMS substrate demonstrated excellent cytocompatibility whereas the stiff one is more cell-repellent.

Bioinspired Ultratough Hydrogel with Fast Recovery, Self-Healing, Injectability and Cytocompatibility.

Science.gov (United States)

Azevedo, Sara; Costa, Ana M S; Andersen, Amanda; Choi, Insung S; Birkedal, Henrik; Mano, João F

2017-07-01

Inspired by the mussel byssus adhesiveness, a highly hydrated polymeric structure is designed to combine, for the first time, a set of interesting features for load-bearing purposes. These characteristics include: i) a compressive strength and stiffness in the MPa range, ii) toughness and the ability to recover it upon successive cyclic loading, iii) the ability to quickly self-heal upon rupture, iv) the possibility of administration through minimally invasive techniques, such as by injection, v) the swelling ratio being adjusted to space-filling applications, and vi) cytocompatibility. Owing to these characteristics and the mild conditions employed, the encapsulation of very unstable and sensitive cargoes is possible, highlighting their potential to researchers in the biomedical field for the repair of load-bearing soft tissues, or to be used as an encapsulation platform for a variety of biological applications such as disease models for drug screening and therapies in a more realistic mechanical environment. Moreover, given the simplicity of this methodology and the enhanced mechanical performance, this strategy can be expanded to applications in other fields, such as agriculture and electronics. As such, it is anticipated that the proposed strategy will constitute a new, versatile, and cost-effective tool to produce engineered polymeric structures for both science and technology. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

UP-scaling of inverted small molecule based organic solar cells

DEFF Research Database (Denmark)

Patil, Bhushan Ramesh; Madsen, Morten

Organic solar cells (OSC), in spite of being a promising technology, still face challenges regarding large-scale fabrication. Although efficiencies of up to 12 % has been reached for small molecule OSC, their performance, both in terms of device efficiency and stability, is significantly reduced...... during up-scaling processes. The work presented here is focused on an approach towards up-scaling of small molecule based OSC with inverted device configuration. Bilayer OSC from Tetraphenyldibenzoperiflanthene (DBP) and Fullerenes (C70), as electron donor and acceptor respectively, with cell area...

Pop-up Library at the University of Birmingham: Extending the Reach of an Academic Library by Taking "The Library" to the Students

Science.gov (United States)

Barnett, James; Bull, Stephen; Cooper, Helen

2016-01-01

Aligning with student engagement and promotional strategies, a Pop-Up Library project was initiated at the University of Birmingham. This involved setting up temporary, staffed stalls in different locations across campus in order to informally communicate with students and effectively take "the Library" to them. This article discusses…

Selection of option of pregame warm-up in handball taking into account features of force of the nervous system of sportsmen

Directory of Open Access Journals (Sweden)

Helen Gant

2016-06-01

Full Text Available Purpose: to develop recommendations about the organization of warm-up for handball players of 13–14 years old taking into account force of the nervous system (NS of players. Material & Methods: 28 handball players of 13–14 years old of Kharkov and Ternovka took part in the research; methods were used: analysis of scientific and methodical literature, technique of "Tapping-test". Results: need of the search of new ways of the increase of efficiency of the competitive activity of young handball players is proved theoretically. Psychological characteristics of handball players of 13–14 years old with a different force of the nervous system are provided. Practical recommendations about the organization of pregame warm-up of handball players of 13–14 years old taking into account force of nervous system of sportsmen are developed. Conclusions: handball players of 13–14 years old can be divided into five groups, concerning force of their nervous system by the results of the conducted research: strong NS (28,57%, average (21,43%, weak (17,86% and average and weak (14,29%, average and strong (17,86%. Recommendations about the organization and carrying out pregame warm-up of handball players of 13–14 years old, taking into account force of the nervous system of sportsmen were developed, considering the results of the psychological research of sportsmen.

Behavioral intention to take up different types of HIV testing among men who have sex with men who were never-testers in Hong Kong.

Science.gov (United States)

Wang, Zixin; Lau, Joseph T F; She, Rui; Ip, Mary; Jiang, Hui; Ho, Shara P Y; Yang, XueYing

2018-01-01

Human immunodeficiency virus (HIV) testing is an important global prevention strategy but underutilized by local men who have sex with men (MSM). This study investigated the prevalence of behavioral intention to take up HIV testing (specific or any type), in the next six months among MSM who had not been tested for HIV in the last three years (never-testers) in Hong Kong. The data was based on 141 never-testers of 430 MSM who completed the anonymous baseline telephone survey of an ongoing randomized controlled trial from January 2015 to August 2015. Only 17.7% of them showed strong intention to take up any type of HIV testing in the next six months. Adjusted analysis showed that perceived benefit of HIV testing (adjusted odds ratio [AOR]: 1.29, 95% confidence interval [CI]: 1.01, 1.66), perceived psychological barriers of HIV testing (AOR: 0.85, 95%CI: 0.73, 1.00), and perceived self-efficacy in taking up HIV testing (AOR: 1.28, 95%CI: 1.07, 1.52) were significantly associated with behavioral intention to take up any HIV testing. Perceived cue to action from non-governmental organization staff was positively associated with a marginal p-value of 0.077 (AOR: 2.37, 95%CI: 0.97, 5.77). It is warranted to strengthen perceived benefit, remove psychological barriers, and increase perceived self-efficacy related to HIV testing. Innovative and effective health promotions are greatly needed to increase HIV testing coverage among never-testers.

Characterization of up-converter layers on bifacial silicon solar cells

International Nuclear Information System (INIS)

Pan, A.C.; Canizo, C. del; Luque, A.

2009-01-01

Photon converters can enhance the performance of solar cells as they have the ability to condition the solar spectrum, thus suiting the semiconductor bandgap better. This paper analyzes the implementation and characterization of rare earth-doped up-converters on bifacial silicon solar cells. The bifacial structures considered absorb the light emitted by the up-converter layer located at the rear of the cell. Two different ways of attaching the up-converter to the bifacial solar cell have been implemented: by dissolving the powder in a spin-on oxide and by dissolving it in a silicone gel. The characterization of this system through measurements of quantum efficiency and photocurrent is described. The measurement setup has been adapted to detect the device response in the NIR (near-infrared) range. A key aspect is the light power impinging on the cell; the system has a quartz-tungsten-halogen lamp as a source, and is capable of giving 240 mW m -2 . As the signals we want to detect are very small, an effort has been made to enhance the signal-to-noise ratio by using a low noise pre-amplifier, optimizing the power of the lamp and reducing the chopper frequency. The characterization of two commercial up-converter materials shows the functioning of the approach, as an increase in the photocurrent when illuminated in the 1500 nm wavelength range is detected in some of the cases.

Chromosome aberrations and rogue cells in lymphocytes of Chernobyl clean-up workers

International Nuclear Information System (INIS)

Lazutka, J.R.

1996-01-01

A cytogenetic analysis was performed on peripheral blood lymphocytes from 183 Chernobyl clean-up workers and 27 control individuals. Increased frequencies of chromosome aberrations were associated with exposure to radiation at Chernobyl, alcohol abuse and a history of recent influenza infection. However, only approximately 20% of Chernobyl clean-up workers had an increased frequency of dicentric and ring chromosomes. At the same time, an increased frequency of acentric fragments in lymphocytes of clean-up workers was characteristic. The use of multivitamins as dietary supplement significantly decreased the frequency of chromosome aberrations, especially of chromatid breaks. Rogue cells were found in lymphocytes of 28 clean-up workers and 3 control individuals. The appearance of rogue cells was associated with a recent history of acute respiratory disease (presumably caused by adenoviral infection) and, probably, alcohol abuse. Dicentric chromosomes in rogue cells were distributed according to a negative binomial distribution. Occurrence of rogue cells due to a perturbation of cell cycle control and abnormal apoptosis is suggested

75 FR 28587 - Taking and Importing Marine Mammals; Taking Marine Mammals Incidental to Missile Launch...

Science.gov (United States)

2010-05-21

... granted for periods up to 5 years if NMFS finds, after notification and opportunity for public comment... such taking. Regulations governing the taking of northern elephant seals (Mirounga angustirostris... would authorize, for a period not to exceed 1 year, take of pinnipeds, by harassment, incidental to...

Taking care: practice and philosophy of communication in a critical care follow-up clinic.

Science.gov (United States)

Hazzard, Anthony; Harris, Wendy; Howell, David

2013-06-01

Human consciousness is inextricable from communication. The conditions of communication in the clinical context are defined by the caring intention and the unequal relationship, which imply special responsibilities on the part of the clinician. The conventional hermeneutic model of communication proposes a close examination of the context of the other, and an objective effort to get close to their consciousness by interpretation of their expressions. The clinician is supposed to lay aside subjective factors but make use of her/his clinical knowledge and skills. At University College Hospital Critical Care follow-up clinic, the communicative task involves history taking; partly by questionnaire and partly by attention to the patient's agenda - assessing needs, providing information and facilitating access to further help. In recent years the provision of Critical Care has become ever more complex, both in terms of the sophisticated medical and nursing techniques it can offer to patients and in the range of conditions it can undertake to treat. This range and complexity is reflected in the variety of problems and consequences that may be encountered at follow-up. Communicative techniques should take account of the emotional vulnerability of patients emerging from severe illness. Attentive listening should identify special anxieties, and care with phraseology aims to avoid further distress. Issues of memory, depression and trauma may be expected, and the interview technique must be flexible enough to offer emotional containment if need be. The consultation should be therapeutic in its conduct but should not embark upon actual psychotherapy or seek to dismantle the patient's defences. Contemporary hermeneutic perspectives emphasise the contextual situatedness of the clinician's consciousness, and propose a model of communication as 'blending of horizons' rather than as objective interpretation. Systems theory contributes to an understanding of the influence on

Biocorrosion behavior and cell viability of adhesive polymer coated magnesium based alloys for medical implants

Energy Technology Data Exchange (ETDEWEB)

Abdal-hay, Abdalla [Departmentt of Bionano System Engineering, College of Engineering, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Department of Mechanical Design Engineering, Advanced wind power system research institute, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Dewidar, Montasser [Department of Materials and Mechanical Design, Faculty of Energy Engineering, South Valley University, Aswan (Egypt); Lim, Jae Kyoo, E-mail: jklim@jbnu.ac.kr [Department of Mechanical Design Engineering, Advanced wind power system research institute, Chonbuk National University, Jeonju 561-756 (Korea, Republic of)

2012-11-15

Highlights: Black-Right-Pointing-Pointer The corrosion behavior of magnesium for orthopedic applications is extremely poor. Black-Right-Pointing-Pointer The solvent (DCM, THF and DMF) had a strong effect on the coatings performance. Black-Right-Pointing-Pointer Mg bar alloy coated with PVAc/DCM layers provided an excellent bonding strength. Black-Right-Pointing-Pointer Treated samples indicated significant damping for the degradation rate. Black-Right-Pointing-Pointer Cytocompatibility on MC3T3 cells of the PVAc/DCM samples revealed a good behavior. - Abstract: The present study was ultimately aimed to design novel adhesive biodegradable polymer, poly(vinyl acetate) (PVAc), coatings onto Mg based alloys by the dip-coating technique in order to control the degradation rate and enhance the biocompatibility of magnesium alloys. The influence of various solvents on PVAc surface topography and their protection of Mg alloys were dramatically studied in vitro. Electrochemical polarization, degradation, and PVAc film cytocompatibility were also tested. Our results showed that the solvent had a significant effect on coating quality. PVAc/dichloromethane solution showed a porous structure and solution concentration could control the porous size. The coatings prepared using tetrahydrofuran and dimethylformamide solvents are exceptional in their ability to generate porous morphology even at low polymer concentration. In general, the corrosion performance appears to be different on different PVAc-solvent system. Immersion tests illustrated that the porous morphology on PVAc stabilized corrosion rates. A uniform corrosion attack in artificial simulation body fluid was also exhibited. The cytocompatibility of osteoblast cells (MC3T3) revealed high adherence, proliferation, and survival on the porous structure of PVAc coated Mg alloy, which was not observed for the uncoated samples. This novel PVAc coating is a promising candidate for biodegradable implant materials, which might

Biocorrosion behavior and cell viability of adhesive polymer coated magnesium based alloys for medical implants

International Nuclear Information System (INIS)

Abdal-hay, Abdalla; Dewidar, Montasser; Lim, Jae Kyoo

2012-01-01

Highlights: ► The corrosion behavior of magnesium for orthopedic applications is extremely poor. ► The solvent (DCM, THF and DMF) had a strong effect on the coatings performance. ► Mg bar alloy coated with PVAc/DCM layers provided an excellent bonding strength. ► Treated samples indicated significant damping for the degradation rate. ► Cytocompatibility on MC3T3 cells of the PVAc/DCM samples revealed a good behavior. - Abstract: The present study was ultimately aimed to design novel adhesive biodegradable polymer, poly(vinyl acetate) (PVAc), coatings onto Mg based alloys by the dip-coating technique in order to control the degradation rate and enhance the biocompatibility of magnesium alloys. The influence of various solvents on PVAc surface topography and their protection of Mg alloys were dramatically studied in vitro. Electrochemical polarization, degradation, and PVAc film cytocompatibility were also tested. Our results showed that the solvent had a significant effect on coating quality. PVAc/dichloromethane solution showed a porous structure and solution concentration could control the porous size. The coatings prepared using tetrahydrofuran and dimethylformamide solvents are exceptional in their ability to generate porous morphology even at low polymer concentration. In general, the corrosion performance appears to be different on different PVAc–solvent system. Immersion tests illustrated that the porous morphology on PVAc stabilized corrosion rates. A uniform corrosion attack in artificial simulation body fluid was also exhibited. The cytocompatibility of osteoblast cells (MC3T3) revealed high adherence, proliferation, and survival on the porous structure of PVAc coated Mg alloy, which was not observed for the uncoated samples. This novel PVAc coating is a promising candidate for biodegradable implant materials, which might widen the use of Mg based implants.

Antimicrobial photodynamic activity and cytocompatibility of Au25(Capt18 clusters photoexcited by blue LED light irradiation

Directory of Open Access Journals (Sweden)

Miyata S

2017-04-01

spectra of oxidized MTX. Successful application of photoexcited Au clusters to aPDT was demonstrated by dose-dependent decreases in the turbidity of oral bacterial cells. Morphological observation revealed that application of Au clusters stimulated destruction of bacterial cell walls and inhibited biofilm formation. Aggregation of Au clusters around bacterial cells was fluorescently observed. However, photoexcited Au clusters did not negatively affect the adhesion, spreading, and proliferation of mammalian cells, particularly at lower doses. In addition, application of Au clusters demonstrated significantly better cytocompatibility ­compared to MB. We found that a combination of Au25(Capt18 clusters and blue LED irradiation exhibited good antimicrobial effects through 1O2 generation and biosafe characteristics, which is desirable for aPDT in dentistry. Keywords: Aggregatibacter actinomycetemcomitans, antimicrobial photodynamic therapy, photosensitizer, Porphyromonas gingivalis, singlet oxygen, Streptococcus mutans

Modified n-HA/PA66 scaffolds with chitosan coating for bone tissue engineering: cell stimulation and drug release.

Science.gov (United States)

Zou, Qin; Li, Junfeng; Niu, Lulu; Zuo, Yi; Li, Jidong; Li, Yubao

2017-09-01

The dipping-drying procedure and cross-linking method were used to make drug-loaded chitosan (CS) coating on nano-hydroxyapatite/polyamide66 (nHA/PA66) composite porous scaffold, endowing the scaffold controlled drug release functionality. The prefabricated scaffold was immersed into an aqueous drug/CS solution in a vacuum condition and then crosslinked by vanillin. The structure, porosity, composition, compressive strength, swelling ratio, drug release and cytocompatibility of the pristine and coating scaffolds were investigated. After coating, the scaffold porosity and pore interconnection were slightly decreased. Cytocompatibility performance was observed through an in vitro experiment based on cell attachment and the MTT assay by MG63 cells which revealed positive cell viability and increasing proliferation over the 11-day period in vitro. The drug could effectively release from the coated scaffold in a controlled fashion and the release rate was sustained for a long period and highly dependent on coating swelling, suggesting the possibility of a controlled drug release. Our results demonstrate that the scaffold with drug-loaded crosslinked CS coating can be used as a simple technique to render the surfaces of synthetic scaffolds active, thus enabling them to be a promising high performance biomaterial in bone tissue engineering.

Dual-functionalized graphene oxide for enhanced siRNA delivery to breast cancer cells.

Science.gov (United States)

Imani, Rana; Shao, Wei; Taherkhani, Samira; Emami, Shahriar Hojjati; Prakash, Satya; Faghihi, Shahab

2016-11-01

The aim of this study is to improve hydrocolloid stability and siRNA transfection ability of a reduced graphene oxide (rGO) based nano-carrier using a phospholipid-based amphiphilic polymer (PL-PEG) and cell penetrating peptide (CPPs). The dual functionalized nano-carrier is comprehensively characterized for its chemical structure, size, surface charge and morphology as well as thermal stability. The nano-carrier cytocompatibility, siRNA condensation ability both in the presence and absence of enzyme, endosomal buffering capacity, cellular uptake and intracellular localization are also assessed. The siRNA loaded nano-carrier is used for internalization to MCF-7 cells and its gene silencing ability is compared with AllStars Hs Cell Death siRNA as a model gene. The nano-carrier remains stable in biological solution, exhibits excellent cytocompatibility, retards the siRNA migration and protects it against enzyme degradation. The buffering capacity analysis shows that incorporation of the peptide in nano-carrier structure would increase the resistance to endo/lysosomal like acidic condition (pH 6-4) The functionalized nano-carrier which is loaded with siRNA in an optimal N:P ratio presents superior internalization efficiency (82±5.1% compared to HiPerFect(®)), endosomal escape quality and capable of inducing cell death in MCF-7 cancer cells (51±3.1% compared to non-treated cells). The success of siRNA-based therapy is largely dependent on the safe and efficient delivery system, therefore; the dual functionalized rGO introduced here could have a great potential to be used as a carrier for siRNA delivery with relevancy in therapeutics and clinical applications. Copyright © 2016 Elsevier B.V. All rights reserved.

Experimental study on the start-up with dry gases from normal cell temperatures in self-humidified proton exchange membrane fuel cells

International Nuclear Information System (INIS)

Kong, Im Mo; Jung, Aeri; Kim, Beom Jun; Baik, Kyung Don; Kim, Min Soo

2015-01-01

In this study, the start-up characteristics of PEMFCs (proton exchange membrane fuel cells) was investigated with dry gases from normal cell temperatures above 0 °C. Firstly, the effects of flow arrangements (co-flow and counter-flow) were evaluated at a starting cell temperature of 25 °C. Then, the start-up was successful in both arrangements, but it showed better performance with counter-flow. In addition, the hydrogen concentration was measured and it showed that hydrogen crossover contributes to the membrane hydration and the first phase of dry start-up. However, although the cell temperature rose above 45 °C after start-up form 25 °C with counter-flow arrangement, the restart-up after shut-down failed at a starting cell temperature of 45 °C regardless of flow arrangements. Considering the needs of restart-up, the available starting cell temperature should be improved. For this, after first sub-step of start-up process, relatively low flow rates were maintained to retain produced water without purge so that the membrane can be hydrated sufficiently. With this modified process, denominated as WSP (water storage process) in this study, the dry start-up became successful at a starting cell temperature of 45 °C and the cell performance was remarkably improved especially with counter-flow arrangement. - Highlights: • Start-up with dry gases from normal cell temperatures was investigated. • Counter-flow arrangement showed better performance over co-flow arrangement. • Water is produced by hydrogen crossover and its direct reaction with oxygen at cathode side. • It prevents the membrane dehydration and helps the start-up during the first phase of the process. • Available starting cell temperature and cell performance could be improved with WSP.

Taking Care of Pressure Sores

Science.gov (United States)

... Tract Infections: Indwelling (Foley) Catheter Taking Care of Pressure Sores [Download this pamphlet: "Taking Care of Pressure Sores" - ( ... may not show up right away. Stages of pressure sores and how to care for them: STAGE ONE ...

Pre-Clinical Studies of Dendritic Cell-Tumor Cell Fusion Vaccines to Treat Breast Cancer

National Research Council Canada - National Science Library

Akporiaye, Emmanuel

2002-01-01

...+ T-helper cells, CD8+ cytotoxic T lymphocytes (CTLs), NK and NKT cells (1,2). Because DC have the capacity to take up various types of molecules, the cells can be loaded with tumor-associated antigens (TAAs...

A novel shell-structure cell microcarrier (SSCM) for cell transplantation and bone regeneration medicine.

Science.gov (United States)

Su, Kai; Gong, Yihong; Wang, Chunming; Wang, Dong-An

2011-06-01

The present study aims to develop a novel open and hollow shell-structure cell microcarrier (SSCM) to improve the anchorage-dependent cell (ADC) loading efficiency, increase the space for cell proliferation and tissue regeneration, and better propel its therapeutic effects. Gelatin particles were prepared with oil/water/oil (o/w/o) technique and modified by an adjustable surface crosslinking technique and subsequent release of uncrosslinked material. Optical microscopy and scanning electron microscopy (SEM) were utilized to observe the morphologies of the microcarriers. Cell loading tests were performed to evaluate the biocompatibilities and effect on osteogenesis of SSCM. SSCMs were successfully fabricated via the surface technique. The shell-structure could allow the cell to attach and grow on both outer and inner surface of sphere and provide adequate space for cell proliferation and extracellular matrix (ECM) secretion. The cell loading rate, proliferation rate and osteogenesis-related gene expressions on the SSCMs were higher than those on the spherical gelatin microcarriers. The outstanding performance of injectable SSCMs endowed with favorable micro-structure, desirable cytocompatibility and enhanced cell affinity makes them as a good choice as cell delivery vehicle for transplanting therapeutic cells towards the scope of tissue regeneration.

Up-regulation of Kir2.1 by ER stress facilitates cell death of brain capillary endothelial cells

International Nuclear Information System (INIS)

Kito, Hiroaki; Yamazaki, Daiju; Ohya, Susumu; Yamamura, Hisao; Asai, Kiyofumi; Imaizumi, Yuji

2011-01-01

Highlights: → We found that application of endoplasmic reticulum (ER) stress with tunicamycin to brain capillary endothelial cells (BCECs) induced cell death. → The ER stress facilitated the expression of inward rectifier K + channel (K ir 2.1) and induced sustained membrane hyperpolarization. → The membrane hyperpolarization induced sustained Ca 2+ entry through voltage-independent nonspecific cation channels and consequently facilitated cell death. → The K ir 2.1 up-regulation by ER stress is, at least in part, responsible for cell death of BCECs under pathological conditions. -- Abstract: Brain capillary endothelial cells (BCECs) form blood brain barrier (BBB) to maintain brain homeostasis. Cell turnover of BCECs by the balance of cell proliferation and cell death is critical for maintaining the integrity of BBB. Here we found that stimuli with tunicamycin, endoplasmic reticulum (ER) stress inducer, up-regulated inward rectifier K + channel (K ir 2.1) and facilitated cell death in t-BBEC117, a cell line derived from bovine BCECs. The activation of K ir channels contributed to the establishment of deeply negative resting membrane potential in t-BBEC117. The deep resting membrane potential increased the resting intracellular Ca 2+ concentration due to Ca 2+ influx through non-selective cation channels and thereby partly but significantly regulated cell death in t-BBEC117. The present results suggest that the up-regulation of K ir 2.1 is, at least in part, responsible for cell death/cell turnover of BCECs induced by a variety of cellular stresses, particularly ER stress, under pathological conditions.

Collagen-IV supported embryoid bodies formation and differentiation from buffalo (Bubalus bubalis) embryonic stem cells

Energy Technology Data Exchange (ETDEWEB)

Taru Sharma, G., E-mail: gts553@gmail.com [Reproductive Physiology Laboratory, Division of Physiology and Climatology, Indian Veterinary Research Institute, Izatnagar-243 122, Bareilly, U.P. (India); Dubey, Pawan K.; Verma, Om Prakash; Pratheesh, M.D.; Nath, Amar; Sai Kumar, G. [Reproductive Physiology Laboratory, Division of Physiology and Climatology, Indian Veterinary Research Institute, Izatnagar-243 122, Bareilly, U.P. (India)

2012-08-03

Graphical abstract: EBs formation, characterization and expression of germinal layers marker genes of in vivo developed teratoma using four different types of extracellular matrices. Highlights: Black-Right-Pointing-Pointer Collagen-IV matrix is found cytocompatible for EBs formation and differentiation. Black-Right-Pointing-Pointer Established 3D microenvironment for ES cells development and differentiation into three germ layers. Black-Right-Pointing-Pointer Collagen-IV may be useful as promising candidate for ES cells based therapeutic applications. -- Abstract: Embryoid bodies (EBs) are used as in vitro model to study early extraembryonic tissue formation and differentiation. In this study, a novel method using three dimensional extracellular matrices for in vitro generation of EBs from buffalo embryonic stem (ES) cells and its differentiation potential by teratoma formation was successfully established. In vitro derived inner cell masses (ICMs) of hatched buffalo blastocyst were cultured on buffalo fetal fibroblast feeder layer for primary cell colony formation. For generation of EBs, pluripotent ES cells were seeded onto four different types of extracellular matrices viz; collagen-IV, laminin, fibronectin and matrigel using undifferentiating ES cell culture medium. After 5 days of culture, ESCs gradually grew into aggregates and formed simple EBs having circular structures. Twenty-six days later, they formed cystic EBs over collagen matrix with higher EBs formation and greater proliferation rate as compared to other extracellular matrices. Studies involving histological observations, fluorescence microscopy and RT-PCR analysis of the in vivo developed teratoma revealed that presence of all the three germ layer derivatives viz. ectoderm (NCAM), mesoderm (Flk-1) and endoderm (AFP). In conclusion, the method described here demonstrates a simple and cost-effective way of generating EBs from buffalo ES cells. Collagen-IV matrix was found cytocompatible as it

Collagen-IV supported embryoid bodies formation and differentiation from buffalo (Bubalus bubalis) embryonic stem cells

International Nuclear Information System (INIS)

Taru Sharma, G.; Dubey, Pawan K.; Verma, Om Prakash; Pratheesh, M.D.; Nath, Amar; Sai Kumar, G.

2012-01-01

Graphical abstract: EBs formation, characterization and expression of germinal layers marker genes of in vivo developed teratoma using four different types of extracellular matrices. Highlights: ► Collagen-IV matrix is found cytocompatible for EBs formation and differentiation. ► Established 3D microenvironment for ES cells development and differentiation into three germ layers. ► Collagen-IV may be useful as promising candidate for ES cells based therapeutic applications. -- Abstract: Embryoid bodies (EBs) are used as in vitro model to study early extraembryonic tissue formation and differentiation. In this study, a novel method using three dimensional extracellular matrices for in vitro generation of EBs from buffalo embryonic stem (ES) cells and its differentiation potential by teratoma formation was successfully established. In vitro derived inner cell masses (ICMs) of hatched buffalo blastocyst were cultured on buffalo fetal fibroblast feeder layer for primary cell colony formation. For generation of EBs, pluripotent ES cells were seeded onto four different types of extracellular matrices viz; collagen-IV, laminin, fibronectin and matrigel using undifferentiating ES cell culture medium. After 5 days of culture, ESCs gradually grew into aggregates and formed simple EBs having circular structures. Twenty-six days later, they formed cystic EBs over collagen matrix with higher EBs formation and greater proliferation rate as compared to other extracellular matrices. Studies involving histological observations, fluorescence microscopy and RT-PCR analysis of the in vivo developed teratoma revealed that presence of all the three germ layer derivatives viz. ectoderm (NCAM), mesoderm (Flk-1) and endoderm (AFP). In conclusion, the method described here demonstrates a simple and cost-effective way of generating EBs from buffalo ES cells. Collagen-IV matrix was found cytocompatible as it supported buffalo EBs formation, their subsequent differentiation could prove to

ATLAS's superconducting solenoid takes up position

CERN Multimedia

2004-01-01

The ATLAS superconducting solenoid was moved to its final destination on 16 January. It has taken up position opposite the ATLAS liquid argon barrel cryostat, which will house the electromagnetic calorimeter. All that remains to do now is to slide it into the insulation vacuum, this will be done in the next few weeks. Built by Toshiba, under responsibility of KEK in Japan, the central solenoid is 2.4 metres in diameter, 5.3 metres long and weighs 5.5 tonnes. "It will provide an axial magnetic field of 2 Tesla that will deflect particles inside the inner detector," as Roger Ruber, on-site project coordinator, explains. The inner detector, which consists of three sub-detectors, will be installed inside the solenoid later. The solenoid during one of the transport operations. Securely attached to the overhead travelling crane, the solenoid is situated in front of the opening to the liquid argon calorimeter, it will be inserted soon.

Photoinitiated chemical vapor deposition of cytocompatible poly(2-hydroxyethyl methacrylate) films.

Science.gov (United States)

McMahon, Brian J; Pfluger, Courtney A; Sun, Bing; Ziemer, Katherine S; Burkey, Daniel D; Carrier, Rebecca L

2014-07-01

Poly(2-hydroxyethyl methacrylate) (pHEMA) is a widely utilized biomaterial due to lack of toxicity and suitable mechanical properties; conformal thin pHEMA films produced via chemical vapor deposition (CVD) would thus have broad biomedical applications. Thin films of pHEMA were deposited using photoinitiated CVD (piCVD). Incorporation of ethylene glycol diacrylate (EGDA) into the pHEMA polymer film as a crosslinker, confirmed via Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy, resulted in varied swelling and degradation behavior. 2-Hydroxyethyl methacrylate-only films showed significant thickness loss (up to 40%), possibly due to extraction of low-molecular-weight species or erosion, after 24 h in aqueous solution, whereas films crosslinked with EGDA (9.25-12.4%) were stable for up to 21 days. These results differ significantly from those obtained with plasma-polymerized pHEMA, which degraded steadily over a 21-day period, even with crosslinking. This suggests that the piCVD films differ structurally from those fabricated via plasma polymerization (plasma-enhanced CVD). piCVD pHEMA coatings proved to be good cell culture materials, with Caco-2 cell attachment and viability comparable to results obtained on tissue-culture polystyrene. Thus, thin film CVD pHEMA offers the advantage of enabling conformal coating of a cell culture substrate with tunable properties depending on method of preparation and incorporation of crosslinking agents. © 2013 Wiley Periodicals, Inc.

Fuel cell/back-up battery hybrid energy conversion systems: Dynamic modeling and harmonic considerations

International Nuclear Information System (INIS)

Fathabadi, Hassan

2015-01-01

Highlights: • Novel technique to completely eliminate the harmful harmonics of fuel cell system. • Presenting a novel high accurate detailed electrochemical dynamic model of fuel cells. • Back-up battery system to compensate the slow dynamic response of fuel cell system. • Exact analysis of real electrochemical reactions occurring inside fuel cells. - Abstract: In this study, a novel dynamic model of fuel cells is presented. High accurate static and dynamic responses of the proposed model are experimentally validated by comparing simulated results with real experimental data. The obtained model together with theoretical results shows that a fuel cell or a fuel cell stack has very slow dynamic response, so that, it cannot adapt itself to the fast variations in load demand. It is shown that for adapting well a fuel cell stack to the load demand, the stack should be equipped with a proposed back-up battery system which compensates the slow dynamic response of the stack by providing a bidirectional path to transmit/absorb the extra instant power. It is proved that the conventional switching waveforms used in the converters of the stacks and back-up systems produce an enormous amount of harmful harmonics. Then, a novel technique is proposed to completely eliminate main harmful harmonics. It is worthwhile to note that all the other techniques only reduce the harmful harmonics. Simulated results verify that the back-up battery system together with applying the proposed technique provide a fast dynamic response for the fuel cell/back-up battery system, and also completely eliminate the main harmful harmonics

Cellular interactions of lauric acid and dextran-coated magnetite nanoparticles

International Nuclear Information System (INIS)

Pradhan, Pallab; Giri, Jyotsnendu; Banerjee, Rinti; Bellare, Jayesh; Bahadur, Dhirendra

2007-01-01

In vitro cytocompatibility and cellular interactions of lauric acid and dextran-coated magnetite nanoparticles were evaluated with two different cell lines (mouse fibroblast and human cervical carcinoma). Lauric acid-coated magnetite nanoparticles were less cytocompatible than dextran-coated magnetite nanoparticles and cellular uptake of lauric acid-coated magnetic nanoparticles was more than that of dextran-coated magnetite nanoparticles. Lesser cytocompatibility and higher uptake of lauric acid-coated magnetite nanoparticles as compared to dextran-coated magnetic nanoparticles may be due to different cellular interactions by coating material. Thus, coating plays an important role in modulation of biocompatibility and cellular interaction of magnetic nanoparticles

Cell adhesion on nanotextured slippery superhydrophobic substrates.

Science.gov (United States)

Di Mundo, Rosa; Nardulli, Marina; Milella, Antonella; Favia, Pietro; d'Agostino, Riccardo; Gristina, Roberto

2011-04-19

In this work, the response of Saos2 cells to polymeric surfaces with different roughness/density of nanometric dots produced by a tailored plasma-etching process has been studied. Topographical features have been evaluated by atomic force microscopy, while wetting behavior, in terms of water-surface adhesion energy, has been evaluated by measurements of drop sliding angle. Saos2 cytocompatibility has been investigated by scanning electron microscopy, fluorescent microscopy, and optical microscopy. The similarity in outer chemical composition has allowed isolation of the impact of the topographical features on cellular behavior. The results indicate that Saos2 cells respond differently to surfaces with different nanoscale topographical features, clearly showing a certain inhibition in cell adhesion when the nanoscale is particularly small. This effect appears to be attenuated in surfaces with relatively bigger nanofeatures, though these express a more pronounced slippery/dry wetting character. © 2011 American Chemical Society

The Bologna Process: Inception, "Take Up" and Familiarity

Science.gov (United States)

Neave, Guy; Veiga, Amelia

2013-01-01

This paper addresses the value of the Bologna Process in placing the European Higher Education Area (EHEA) on a solid institutional footing. How far has Bologna contributed to firming up the views academia, management and students have of the EHEA? The article is based on a survey administered across four systems of higher education in 2008. It…

Work Station For Inverting Solar Cells

Science.gov (United States)

Feder, H.; Frasch, W.

1982-01-01

Final work station along walking-beam conveyor of solar-array assembly line turns each pretabbed solar cell over, depositing it back-side-up onto landing pad, which centers cell without engaging collector surface. Solar cell arrives at inverting work station collector-side-up with two interconnect tabs attached to collector side. Cells are inverted so that second soldering operation takes place in plain view of operator. Inversion protects collector from damage when handled at later stages of assembly.

Physicochemical and osteoplastic characteristics of 3D printed bone grafts based on synthetic calcium phosphates and natural polymers

Science.gov (United States)

Nezhurina, E. K.; Karalkin, P. A.; Komlev, V. S.; Sviridova, I. K.; Kirsanova, V. A.; Akhmedova, S. A.; Shanskiy, Ya D.; Fedotov, A. Yu; Barinov, S. M.; Sergeeva, N. S.

2018-04-01

A creation of personalized implants for regeneration of bone tissue seems to be a very promising biomedical technological approach. We have studied the physicochemical characteristics, cyto- and biocompatibility of three-dimensional constructs based on sodium alginate and gelatin in combination with 2 types of calcium phosphate (tricalcium phosphate or octacalcium phosphate) obtained by inkjet 3D printing. In our experiments, we have studied the physical and chemical properties of the constructs – their porosity, chemical composition, microarchitecture of the surface and mechanical elasticity. The cytocompatibility of 3D constructs and matrix-for-cell properties were investigated in vitro on a model of human osteosarcoma MG-63 cell line by means of MTT assay. The biocompatibility of 3D constructs was studied on the model of subcutaneous implantation in mice up to 12 weeks. All types of 3D constructs were cytocompatible in vitro, demonstrated good matrix-for-cells properties, and had supported cell proliferation for 2 weeks. In results of subcutaneous in vivo test all constructs demonstrated biocompatibility with slow bioresorption of organic and inorganic components. Osteogenesis proceeded more actively in rat tibia model defects (marginal excision), substituted by 3D printed 3-component implants based on alginate, gelatin and octacalcium phosphate.

Neural cell 3D microtissue formation is marked by cytokines' up-regulation.

Directory of Open Access Journals (Sweden)

Yinzhi Lai

Full Text Available Cells cultured in three dimensional (3D scaffolds as opposed to traditional two-dimensional (2D substrates have been considered more physiologically relevant based on their superior ability to emulate the in vivo environment. Combined with stem cell technology, 3D cell cultures can provide a promising alternative for use in cell-based assays or biosensors in non-clinical drug discovery studies. To advance 3D culture technology, a case has been made for identifying and validating three-dimensionality biomarkers. With this goal in mind, we conducted a transcriptomic expression comparison among neural progenitor cells cultured on 2D substrates, 3D porous polystyrene scaffolds, and as 3D neurospheres (in vivo surrogate. Up-regulation of cytokines as a group in 3D and neurospheres was observed. A group of 13 cytokines were commonly up-regulated in cells cultured in polystyrene scaffolds and neurospheres, suggesting potential for any or a combination from this list to serve as three-dimensionality biomarkers. These results are supportive of further cytokine identification and validation studies with cells from non-neural tissue.

Limiting efficiency of generalized realistic c-Si solar cells coupled to ideal up-converters

Science.gov (United States)

Johnson, Craig M.; Conibeer, Gavin J.

2012-11-01

The detailed balance model of photovoltaic up-conversion is revised for the specific case of a c-Si solar cell under the AM1.5G solar spectrum. The limiting efficiency of an ideal solar cell with a band gap of 1.117 eV may be increased from approximately 33% to 40% with ideal up-conversion. However, real solar cells do not demonstrate the step-function absorption characteristic assumed in the standard detailed balance model. Here, we use tabulated Si refractive index data to develop a generalized model of a realistic conventional c-Si solar cell. The model incorporates optical design and material parameters such as free carrier absorption that have a non-trivial impact on the operation of the up-conversion layer. While these modifications are shown to decrease the absolute limiting efficiency, the benefit of up-conversion is shown to be relatively greater.

Scale-up of hydrophobin-assisted recombinant protein production in tobacco BY-2 suspension cells.

Science.gov (United States)

Reuter, Lauri J; Bailey, Michael J; Joensuu, Jussi J; Ritala, Anneli

2014-05-01

Plant suspension cell cultures are emerging as an alternative to mammalian cells for production of complex recombinant proteins. Plant cell cultures provide low production cost, intrinsic safety and adherence to current regulations, but low yields and costly purification technology hinder their commercialization. Fungal hydrophobins have been utilized as fusion tags to improve yields and facilitate efficient low-cost purification by surfactant-based aqueous two-phase separation (ATPS) in plant, fungal and insect cells. In this work, we report the utilization of hydrophobin fusion technology in tobacco bright yellow 2 (BY-2) suspension cell platform and the establishment of pilot-scale propagation and downstream processing including first-step purification by ATPS. Green fluorescent protein-hydrophobin fusion (GFP-HFBI) induced the formation of protein bodies in tobacco suspension cells, thus encapsulating the fusion protein into discrete compartments. Cultivation of the BY-2 suspension cells was scaled up in standard stirred tank bioreactors up to 600 L production volume, with no apparent change in growth kinetics. Subsequently, ATPS was applied to selectively capture the GFP-HFBI product from crude cell lysate, resulting in threefold concentration, good purity and up to 60% recovery. The ATPS was scaled up to 20 L volume, without loss off efficiency. This study provides the first proof of concept for large-scale hydrophobin-assisted production of recombinant proteins in tobacco BY-2 cell suspensions. © 2013 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

Highly versatile nanohydrogel platform based on riboflavin-polysaccharide derivatives useful in the development of intrinsically fluorescent and cytocompatible drug carriers.

Science.gov (United States)

Di Meo, Chiara; Montanari, Elita; Manzi, Lucio; Villani, Claudio; Coviello, Tommasina; Matricardi, Pietro

2015-01-22

In this work we describe a new nanohydrogel platform, based on polysaccharides modified with the hydrophobic and fluorescent molecule riboflavin tetrabutyrate, which leads to innovative structures useful for drug delivery applications. Hyaluronic acid and pullulan were chosen as representative of anionic and neutral polysaccharides, respectively, and the bromohexyl derivative of riboflavin tetrabutyrate was chemically linked to these polymer chains. Because of such derivatization, polymer chains were able to self-assemble in aqueous environment thus forming nanohydrogels, with mean diameters of about 312 and 210 nm, for hyaluronan and pullulan, respectively. These new nanohydrogels showed low polydispersity index, and negative ζ-potential. Moreover, the nanohydrogels, which can be easily loaded with model drugs, showed long-term stability in water and physiological conditions and excellent cytocompatibility. All these properties allow to consider these intrinsically fluorescent nanohydrogels suitable for the formulation of innovative drug dosage forms. Copyright © 2014 Elsevier Ltd. All rights reserved.

Vertically aligned carbon nanotubes as cytocompatible material for enhanced adhesion and proliferation of osteoblast-like cells.

Science.gov (United States)

Giannona, Suna; Firkowska, Izabela; Rojas-Chapana, José; Giersig, Michael

2007-01-01

In this study, we describe the spatial organization of CAL-72 osteoblast-like cells on arrays of vertically aligned multi-walled carbon nanotubes (VACNTs). It was observed that, unlike cell growth on non-patterned surfaces, the cell attachment and spreading process on VACNTs was significantly enhanced. Additionally, since carbon nanotubes are known to possess resilient mechanical properties and are chemically stable, the effect of periodic arrays of VACNTs on CAL-72 osteoblast-like cells was also studied. The periodicity and alignment of VACNTs considerably influenced growth, shape and orientation of the cells by steering toward the nanopattern. This situation is of great interest for the potential application of VACNTs in bone bioenginnering. This data provides evidence that CAL-72 osteoblast-like cells can sense physical features at the nanoscale. These results give a fascinating insight into the ways in which cell growth can be influenced by man-made nanostructures and could provide a framework for achieving controlled cell guidance with controlled organization and special physical properties.

Up-regulation of K{sub ir}2.1 by ER stress facilitates cell death of brain capillary endothelial cells

Energy Technology Data Exchange (ETDEWEB)

Kito, Hiroaki [Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya (Japan); Yamazaki, Daiju [Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya (Japan); Department of Biological Chemistry, Kyoto University, Graduate School of Pharmaceutical Sciences, Kyoto (Japan); Department of Molecular Neurobiology, Graduate School of Medical Sciences, Nagoya City University, Nagoya (Japan); Ohya, Susumu; Yamamura, Hisao [Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya (Japan); Asai, Kiyofumi [Department of Molecular Neurobiology, Graduate School of Medical Sciences, Nagoya City University, Nagoya (Japan); Imaizumi, Yuji, E-mail: yimaizum@phar.nagoya-cu.ac.jp [Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya (Japan)

2011-07-29

Highlights: {yields} We found that application of endoplasmic reticulum (ER) stress with tunicamycin to brain capillary endothelial cells (BCECs) induced cell death. {yields} The ER stress facilitated the expression of inward rectifier K{sup +} channel (K{sub ir}2.1) and induced sustained membrane hyperpolarization. {yields} The membrane hyperpolarization induced sustained Ca{sup 2+} entry through voltage-independent nonspecific cation channels and consequently facilitated cell death. {yields} The K{sub ir}2.1 up-regulation by ER stress is, at least in part, responsible for cell death of BCECs under pathological conditions. -- Abstract: Brain capillary endothelial cells (BCECs) form blood brain barrier (BBB) to maintain brain homeostasis. Cell turnover of BCECs by the balance of cell proliferation and cell death is critical for maintaining the integrity of BBB. Here we found that stimuli with tunicamycin, endoplasmic reticulum (ER) stress inducer, up-regulated inward rectifier K{sup +} channel (K{sub ir}2.1) and facilitated cell death in t-BBEC117, a cell line derived from bovine BCECs. The activation of K{sub ir} channels contributed to the establishment of deeply negative resting membrane potential in t-BBEC117. The deep resting membrane potential increased the resting intracellular Ca{sup 2+} concentration due to Ca{sup 2+} influx through non-selective cation channels and thereby partly but significantly regulated cell death in t-BBEC117. The present results suggest that the up-regulation of K{sub ir}2.1 is, at least in part, responsible for cell death/cell turnover of BCECs induced by a variety of cellular stresses, particularly ER stress, under pathological conditions.

System to take up oil suspended in water. System zur Aufnahme von Wasser schwimmendem Oel

Energy Technology Data Exchange (ETDEWEB)

Skowronek, A; Hahnefeld, J

1981-03-19

This sytem for taking up oil suspended in water has the advantage that the material required can be jettisoned by aircraft in areas affected by an oil catastrophy. Two hoses about 100 metres distant from one another pull a plastic cover made of Perlon through the water. The upper edge of the cover widens into hose-like air containers, in order to keep the cover sufficiently above the water. The lower edge is loaded with quartz sand, in order to keep the cover vertical in the water. A connecting piece guides the oil into a connected plastic pontoon. There are two ships engines mounted in the front third of the connecting piece, which pump the oil into the first pontoon, which acts as storage container. Two dewatering valves are situated in it, which will separate the oil from the water. After passing through this pontoon, the oil reaches a second, much larger plastic pontoon, which acts as the collector for pure oil.

Plant nutrient acquisition strategies in tundra species: at which soil depth do species take up their nitrogen?

Science.gov (United States)

Limpens, Juul; Heijmans, Monique; Nauta, Ake; van Huissteden, Corine; van Rijssel, Sophie

2016-04-01

The Arctic is warming at unprecedented rates. Increased thawing of permafrost releases nutrients locked up in the previously frozen soils layers, which may initiate shifts in vegetation composition. The direction in which the vegetation shifts will co-determine whether Arctic warming is mitigated or accelerated, making understanding successional trajectories urgent. One of the key factors influencing the competitive relationships between plant species is their access to nutrients, in particularly nitrogen (N). We assessed the depth at which plant species took up N by performing a 15N tracer study, injecting 15(NH4)2SO4 at three depths (5, 15, 20 cm) into the soil in arctic tundra in north-eastern Siberia in July. In addition we explored plant nutrient acquisition strategy by analyzing natural abundances of 15N in leaves. We found that vascular plants took up 15N at all injection depths, irrespective of species, but also that species showed a clear preference for specific soil layers that coincided with their functional group (graminoids, dwarf shrubs, cryptogams). Graminoids took up most 15N at 20 cm depth nearest to the thaw front, with grasses showing a more pronounced preference than sedges. Dwarf shrubs took up most 15N at 5 cm depth, with deciduous shrubs displaying more preference than evergreens. Cryptogams did not take up any of the supplied 15N . The natural 15N abundances confirmed the pattern of nutrient acquisition from deeper soil layers in graminoids and from shallow soil layers in both deciduous and evergreen dwarf shrubs. Our results prove that graminoids and shrubs differ in their N uptake strategies, with graminoids profiting from nutrients released at the thaw front, whereas shrubs forage in the upper soil layers. The above implies that graminoids, grasses in particular, will have a competitive advantage over shrubs as the thaw front proceeds and/or superficial soil layers dry out. Our results suggest that the vertical distribution of nutrients

Hypoxic stress up-regulates Kir2.1 expression and facilitates cell proliferation in brain capillary endothelial cells

International Nuclear Information System (INIS)

Yamamura, Hideto; Suzuki, Yoshiaki; Yamamura, Hisao; Asai, Kiyofumi; Imaizumi, Yuji

2016-01-01

The blood-brain barrier (BBB) is mainly composed of brain capillary endothelial cells (BCECs), astrocytes and pericytes. Brain ischemia causes hypoxic encephalopathy and damages BBB. However, it remains still unclear how hypoxia affects BCECs. In the present study, t-BBEC117 cells, an immortalized bovine brain endothelial cell line, were cultured under hypoxic conditions at 4–5% oxygen for 72 h. This hypoxic stress caused hyperpolarization of resting membrane potential. Patch-clamp recordings revealed a marked increase in Ba 2+ -sensitive inward rectifier K + current in t-BBEC117 cells after hypoxic culture. Western blot and real-time PCR analyses showed that Kir2.1 expression was significantly up-regulated at protein level but not at mRNA level after the hypoxic culture. Ca 2+ imaging study revealed that the hypoxic stress enhanced store-operated Ca 2+ (SOC) entry, which was significantly reduced in the presence of 100 μM Ba 2+ . On the other hand, the expression of SOC channels such as Orai1, Orai2, and transient receptor potential channels was not affected by hypoxic stress. MTT assay showed that the hypoxic stress significantly enhanced t-BBEC117 cell proliferation, which was inhibited by approximately 60% in the presence of 100 μM Ba 2+ . We first show here that moderate cellular stress by cultivation under hypoxic conditions hyperpolarizes membrane potential via the up-regulation of functional Kir2.1 expression and presumably enhances Ca 2+ entry, resulting in the facilitation of BCEC proliferation. These findings suggest potential roles of Kir2.1 expression in functional changes of BCECs in BBB following ischemia. -- Highlights: •Hypoxic culture of brain endothelial cells (BEC) caused membrane hyperpolarization. •This hyperpolarization was due to the increased expression of Kir2.1 channels. •Hypoxia enhanced store-operated Ca 2+ (SOC) entry via Kir2.1 up-regulation. •Expression levels of putative SOC channels were not affected by hypoxia. �

Neuropilin 1 Receptor Is Up-Regulated in Dysplastic Epithelium and Oral Squamous Cell Carcinoma.

Science.gov (United States)

Shahrabi-Farahani, Shokoufeh; Gallottini, Marina; Martins, Fabiana; Li, Erik; Mudge, Dayna R; Nakayama, Hironao; Hida, Kyoko; Panigrahy, Dipak; D'Amore, Patricia A; Bielenberg, Diane R

2016-04-01

Neuropilins are receptors for disparate ligands, including proangiogenic factors such as vascular endothelial growth factor and inhibitory class 3 semaphorin (SEMA3) family members. Differentiated cells in skin epithelium and cutaneous squamous cell carcinoma highly express the neuropilin-1 (NRP1) receptor. We examined the expression of NRP1 in human and mouse oral mucosa. NRP1 was significantly up-regulated in oral epithelial dysplasia and oral squamous cell carcinoma (OSCC). NRP1 receptor localized to the outer suprabasal epithelial layers in normal tongue, an expression pattern similar to the normal skin epidermis. However, dysplastic tongue epithelium and OSCC up-regulated NRP1 in basal and proliferating epithelial layers, a profile unseen in cutaneous squamous cell carcinoma. NRP1 up-regulation is observed in a mouse carcinogen-induced OSCC model and in human tongue OSCC biopsies. Human OSCC cell lines express NRP1 protein in vitro and in mouse tongue xenografts. Sites of capillary infiltration into orthotopic OSCC tumors correlate with high NRP1 expression. HSC3 xenografts, which express the highest NRP1 levels of the cell lines examined, showed massive intratumoral lymphangiogenesis. SEMA3A inhibited OSCC cell migration, suggesting that the NRP1 receptor was bioactive in OSCC. In conclusion, NRP1 is regulated in the oral epithelium and is selectively up-regulated during epithelial dysplasia. NRP1 may function as a reservoir to sequester proangiogenic ligands within the neoplastic compartment, thereby recruiting neovessels toward tumor cells. Copyright © 2016 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

Thixotropic injectable hydrogel using a polyampholyte and nanosilicate prepared directly after cryopreservation

Energy Technology Data Exchange (ETDEWEB)

Jain, Minkle; Matsumura, Kazuaki, E-mail: mkazuaki@jaist.ac.jp

2016-12-01

Success of tissue engineering applications in regenerative medicine requires the preservation of tissue-engineered products at a low temperature. This can be successfully achieved by the use of cryoprotective agent (CPA). In this study, we formulated a unique injectable hydrogel for the purpose of cell delivery after cryopreservation by using polyampholyte CPA. The polyampholyte showed excellent post-thaw cell survival, and after thawing, the polymeric CPA did not have to be removed because of its low cytotoxicity. The polyampholyte could be transformed into a hydrogel by mixing with nanosilicates. Previously, nanosilicates were used to improve mechanical properties, but this is the first report of the use of a nanosilicate together with CPA to formulate hydrogels. Inclusion of the nanosilicate led to the formation of thixotropic hydrogels, which can be injected using fine needles. These gels with tunable mechanical properties can be injected into defect sites to form scaffolds for cell growth and tissue repair, and they do not require any separate seeding of cells before injection, thus eliminating the need for cell harvesting and cell maintenance. This is a distinct system in which cells can be cryopreserved until before usage; when required, the cells in the polyampholyte can be revived to their original state and the thixotropic hydrogel can be formed. The combination of thixotropy and cytocompatibility of the gels could enable a wide range of biomedical applications such as cell delivery and orthopedic repair. - Graphical abstract: A novel thixotropic, cytocompatible and injectable nanocomposite hydrogel with tunable mechanical properties directly after cryopreservation was formulated using an efficient polymer cryoprotectant and laponite. This is an efficient system in which cells remain viable and can proliferate even after one week. The combined use of thixotropy and cytocompatibility enables this system to be used for cell delivery applications

Plumbagin Nanoparticles Induce Dose and pH Dependent Toxicity on Prostate Cancer Cells.

Science.gov (United States)

Nair, Harikrishnan A; Snima, K S; Kamath, Ravindranath C; Nair, Shantikumar V; Lakshmanan, Vinoth-Kumar

2015-01-01

Stable nano-formulation of Plumbagin nanoparticles from Plumbago zeylanica root extract was explored as a potential natural drug against prostate cancer. Size and morphology analysis by DLS, SEM and AFM revealed the average size of nanoparticles prepared was 100±50nm. In vitro cytotoxicity showed concentration and time dependent toxicity on prostate cancer cells. However, plumbagin crude extract found to be highly toxic to normal cells when compared to plumbagin nanoformulation, thus confirming nano plumbagin cytocompatibility with normal cells and dose dependent toxicity to prostate cells. In vitro hemolysis assay confirmed the blood biocompatibility of the plumbagin nanoparticles. In wound healing assay, plumbagin nanoparticles provided clues that it might play an important role in the anti-migration of prostate cancer cells. DNA fragmentation revealed that partial apoptosis induction by plumbagin nanoparticles could be expected as a potent anti-cancer effect towards prostate cancer.

Gold nanoparticle size and shape influence on osteogenesis of mesenchymal stem cells

Science.gov (United States)

Li, Jingchao; Li, Jia'en Jasmine; Zhang, Jing; Wang, Xinlong; Kawazoe, Naoki; Chen, Guoping

2016-04-01

Gold nanoparticles (AuNPs) have been extensively explored for biomedical applications due to their advantages of facile synthesis and surface functionalization. Previous studies have suggested that AuNPs can induce differentiation of stem cells into osteoblasts. However, how the size and shape of AuNPs affect the differentiation response of stem cells has not been elucidated. In this work, a series of bovine serum albumin (BSA)-coated Au nanospheres, Au nanostars and Au nanorods with different diameters of 40, 70 and 110 nm were synthesized and their effects on osteogenic differentiation of human mesenchymal stem cells (hMSCs) were investigated. All the AuNPs showed good cytocompatibility and did not influence proliferation of hMSCs at the studied concentrations. Osteogenic differentiation of hMSCs was dependent on the size and shape of AuNPs. Sphere-40, sphere-70 and rod-70 significantly increased the alkaline phosphatase (ALP) activity and calcium deposition of cells while rod-40 reduced the ALP activity and calcium deposition. Gene profiling revealed that the expression of osteogenic marker genes was down-regulated after incubation with rod-40. However, up-regulation of these genes was found in the sphere-40, sphere-70 and rod-70 treatment. Moreover, it was found that the size and shape of AuNPs affected the osteogenic differentiation of hMSCs through regulating the activation of Yes-associated protein (YAP). These results indicate that the size and shape of AuNPs had an influence on the osteogenic differentiation of hMSCs, which should provide useful guidance for the preparation of AuNPs with defined size and shape for their biomedical applications.Gold nanoparticles (AuNPs) have been extensively explored for biomedical applications due to their advantages of facile synthesis and surface functionalization. Previous studies have suggested that AuNPs can induce differentiation of stem cells into osteoblasts. However, how the size and shape of AuNPs affect the

Risk factors of vitamin D deficiency in children with epilepsy taking anticonvulsants at initial and during follow-up

Directory of Open Access Journals (Sweden)

Seung Ho Lee

2015-12-01

Full Text Available PurposeVitamin D status was evaluated in children with epilepsy taking anticonvulsants to determine the prevalence and risk factors of vitamin D deficiency.MethodsThis study was designed as both a cross-sectional and a retrospective cohort study. A sum of 198 children who were diagnosed with epilepsy at the Department of Pediatrics in Dankook University Hospital was included. Their serum vitamin D levels were reviewed based on clinical information, and analyzed using IBM SPSS ver. 20.0.ResultsOne hundred twenty-four children (62.6% had vitamin D deficiency. Two risk factors were associated: winter to spring season (odds ratio [OR], 3.71; 95% confidence interval [CI], 1.835-7.492 and age more than 12 years (OR, 3.22; 95% CI, 1.377-7.542. Out of the 57 patients who were not vitamin D deficient at the time of initial assay, 47 patients (82.5% became vitamin D deficient during followup. The change of serum 25-hydroxy vitamin D3 (25(OHD levels during follow up showed a weak negative correlation with the duration of medication (r=-0.283, P=0.033. Medication duration was longer and brain magnetic resonance imaging (MRI abnormality, abnormal underlying conditions, and nonambulatory status were more frequently present in twenty-five patients (44% who showed a decline of more than 15 ng/mL during follow-up (P<0.05.ConclusionVitamin D deficiency is common in children with epilepsy taking anticonvulsants, especially in adolescents more than 12 years of age. This study emphasizes the regular monitoring of vitamin D level, especially in the presence of longer duration of medication, brain MRI abnormality, abnormal underlying conditions, and nonambulatory status.

Polymer and organic solar cells viewed as thin film technologies: What it will take for them to become a success outside academia

DEFF Research Database (Denmark)

Krebs, Frederik C; Jørgensen, Mikkel

2013-01-01

The polymer and organic solar cell technology is critically presented in the context of other thin film technologies with a specific focus on what it will take to make them a commercial success. The academic success of polymer and organic solar cells far outweigh any other solar cell technology w...

Characterization of the Properties of Photopatterned Hydrogels for Use in Regenerative Medicine

Science.gov (United States)

Fiedler, Callie Irene

The goal of this thesis was to locally photopattern cytocompatible hydrogels to exhibit a wide range of mechanical properties and to probe the fundamental parameters governing these materials printed via stereolithography (SLA). Fabricating cell-laden structures with locally defined mechanical properties is non-trivial because the use of multiple precursor materials is wasteful, slow, and can lead to cell-death. To investigate the range of mechanical properties a single precursor solution can produce, I initially formed a single-network hydrogel and cyclically in- swelled fresh precursor solution followed by photo-exposure of the swollen gel ("swelling + exposure" or SE cycle). Because transport (i.e., diffusion and swelling) can occur on the same time scale as photopolymerization reaction kinetics, I first characterized the variable modulus hydrogels in bulk to isolate the reaction kinetics. In these experiments, I demonstrated the ability modify the mechanical and chemical (i.e., compressive modulus, toughness, crosslink density, swelling ratio) properties by up to 10-fold using only 2-4 SE cycles. I then used the understanding gained via these bulk experiments to locally photopattern the elastic modulus of a cytocompatible hydrogel with pixel-limited resolution (˜10s mum) employing a custom SLA system. Here I demonstrated the ability to fabricate hydrogels with a 500% elastic moduli increase with respect to the unpatterned hydrogel using atomic force microscopy. I monitored monomer attachment to the existing matrix as a function of SE cycle using confocal fluorescence microscopy to characterize the shape and size of printed features. I validated that the dependence of these features on material and processing conditions could be explained by a first-order reaction/diffusion model. With this understanding, I fabricated SLA 3D printed, soft, cytocompatible hydrogels (˜10s kPa) with ˜250 mum channels in addition to fabricating 3D printed stiff, cytocompatible

Taking minutes of meetings

CERN Document Server

Gutmann, Joanna

2016-01-01

aking Minutes of Meetings guides you through the entire process behind minute taking: arranging the meeting; writing the agenda; creating the optimum environment; structuring the meeting and writing notes up accurately. The minute-taker is one of the most important and powerful people in a meeting and you can use this opportunity to develop your knowledge, broaden your horizons and build credibility within the organization. Taking Minutes of Meetings is an easy to read 'dip-in, dip-out' guide which shows you how to confidently arrange meetings and produce minutes. It provides hands-on advice about the sections of a meeting as well as tips on how to create an agenda, personal preparation, best practice advice on taking notes and how to improve your accuracy. Brand new chapters of this 4th edition include guidance on using technology to maximize effectiveness and practical help with taking minutes for a variety of different types of meetings. The creating success series of books... With over one million copi...

Glycosaminoglycan-functionalized poly-lactide-co-glycolide nanoparticles: synthesis, characterization, cytocompatibility, and cellular uptake

Directory of Open Access Journals (Sweden)

Lamichhane SP

2015-01-01

Full Text Available Surya P Lamichhane,1 Neha Arya,1,2 Nirdesh Ojha,3 Esther Kohler,1 V Prasad Shastri1,2,41Institute for Macromolecular Chemistry, University of Freiburg, Freiburg, 2Helmholtz Virtual Institute on “Multifunctional Biomaterials for Medicine”, 3Laboratory for Process Technology, Department of Microsystems Engineering, University of Freiburg, Freiburg, 4Centre for Biological Signaling Studies (BIOSS, University of Freiburg, Freiburg, GermanyAbstract: The efficient delivery of chemotherapeutics to the tumor via nanoparticle (NP-based delivery systems remains a significant challenge. This is compounded by the fact that the tumor is highly dynamic and complex environment composed of a plurality of cell types and extracellular matrix. Since glycosaminoglycan (GAG production is altered in many diseases (or pathologies, NPs bearing GAG moieties on the surface may confer some unique advantages in interrogating the tumor microenvironment. In order to explore this premise, in the study reported here poly-lactide-co-glycolide (PLGA NPs in the range of 100–150 nm bearing various proteoglycans were synthesized by a single-step nanoprecipitation and characterized. The surface functionalization of the NPs with GAG moieties was verified using zeta potential measurements and X-ray photoelectron spectroscopy. To establish these GAG-bearing NPs as carriers of therapeutics, cellular toxicity assays were undertaken in lung epithelial adenocarcinoma (A549 cells, human pulmonary microvascular endothelial cells (HPMEC, and renal proximal tubular epithelial cells. In general NPs were well tolerated over a wide concentration range (100–600 µg/mL by all cell types and were taken up to appreciable extents without any adverse cell response in A549 cells and HPMEC. Further, GAG-functionalized PLGA NPs were taken up to different extents in A459 cells and HPMEC. In both cell systems, the uptake of heparin-modified NPs was diminished by 50%–65% in comparison to that of

Tissue strands as "bioink" for scale-up organ printing.

Science.gov (United States)

Yu, Yin; Ozbolat, Ibrahim T

2014-01-01

Organ printing, takes tissue spheroids as building blocks together with additive manufacturing technique to engineer tissue or organ replacement parts. Although a wide array of cell aggregation techniques has been investigated, and gained noticeable success, the application of tissue spheroids for scale-up tissue fabrication is still worth investigation. In this paper, we introduce a new micro-fabrication technique to create tissue strands at the scale of 500-700μm as a "bioink" for future robotic tissue printing. Printable alginate micro-conduits are used as semi-permeable capsules for tissue strand fabrication. Mouse insulinoma beta TC3 cell tissue strands were formed upon 4 days post fabrication with reasonable mechanical strength, high cell viability close to 90%, and tissue specific markers expression. Fusion was readily observed between strands when placing them together as early as 24h. Also, tissue strands were deposited with human umbilical vein smooth muscle cells (HUVSMCs) vascular conduits together to fabricated miniature pancreatic tissue analog. Our study provided a novel technique using tissue strands as "bioink" for scale-up bioprinting of tissues or organs.

Hypoxic stress up-regulates Kir2.1 expression and facilitates cell proliferation in brain capillary endothelial cells

Energy Technology Data Exchange (ETDEWEB)

Yamamura, Hideto; Suzuki, Yoshiaki; Yamamura, Hisao [Department of Molecular & Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya (Japan); Asai, Kiyofumi [Department of Molecular Neurobiology, Graduate School of Medical Sciences, Nagoya City University, Nagoya (Japan); Imaizumi, Yuji, E-mail: yimaizum@phar.nagoya-cu.ac.jp [Department of Molecular & Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya (Japan)

2016-08-05

The blood-brain barrier (BBB) is mainly composed of brain capillary endothelial cells (BCECs), astrocytes and pericytes. Brain ischemia causes hypoxic encephalopathy and damages BBB. However, it remains still unclear how hypoxia affects BCECs. In the present study, t-BBEC117 cells, an immortalized bovine brain endothelial cell line, were cultured under hypoxic conditions at 4–5% oxygen for 72 h. This hypoxic stress caused hyperpolarization of resting membrane potential. Patch-clamp recordings revealed a marked increase in Ba{sup 2+}-sensitive inward rectifier K{sup +} current in t-BBEC117 cells after hypoxic culture. Western blot and real-time PCR analyses showed that Kir2.1 expression was significantly up-regulated at protein level but not at mRNA level after the hypoxic culture. Ca{sup 2+} imaging study revealed that the hypoxic stress enhanced store-operated Ca{sup 2+} (SOC) entry, which was significantly reduced in the presence of 100 μM Ba{sup 2+}. On the other hand, the expression of SOC channels such as Orai1, Orai2, and transient receptor potential channels was not affected by hypoxic stress. MTT assay showed that the hypoxic stress significantly enhanced t-BBEC117 cell proliferation, which was inhibited by approximately 60% in the presence of 100 μM Ba{sup 2+}. We first show here that moderate cellular stress by cultivation under hypoxic conditions hyperpolarizes membrane potential via the up-regulation of functional Kir2.1 expression and presumably enhances Ca{sup 2+} entry, resulting in the facilitation of BCEC proliferation. These findings suggest potential roles of Kir2.1 expression in functional changes of BCECs in BBB following ischemia. -- Highlights: •Hypoxic culture of brain endothelial cells (BEC) caused membrane hyperpolarization. •This hyperpolarization was due to the increased expression of Kir2.1 channels. •Hypoxia enhanced store-operated Ca{sup 2+} (SOC) entry via Kir2.1 up-regulation. •Expression levels of putative SOC

Lack of T-cell receptor-induced signaling is crucial for CD95 ligand up-regulation and protects cutaneous T-cell lymphoma cells from activation-induced cell death.

Science.gov (United States)

Klemke, Claus-Detlev; Brenner, Dirk; Weiss, Eva-Maria; Schmidt, Marc; Leverkus, Martin; Gülow, Karsten; Krammer, Peter H

2009-05-15

Restimulation of previously activated T cells via the T-cell receptor (TCR) leads to activation-induced cell death (AICD), which is, at least in part, dependent on the death receptor CD95 (APO-1, FAS) and its natural ligand (CD95L). Here, we characterize cutaneous T-cell lymphoma (CTCL) cells (CTCL tumor cell lines and primary CTCL tumor cells from CTCL patients) as AICD resistant. We show that CTCL cells have elevated levels of the CD95-inhibitory protein cFLIP. However, cFLIP is not responsible for CTCL AICD resistance. Instead, our data suggest that reduced TCR-proximal signaling in CTCL cells is responsible for the observed AICD resistance. CTCL cells exhibit no PLC-gamma1 activity, resulting in an impaired Ca(2+)release and reduced generation of reactive oxygen species upon TCR stimulation. Ca(2+) and ROS production are crucial for up-regulation of CD95L and reconstitution of both signals resulted in AICD sensitivity of CTCL cells. In accordance with these data, CTCL tumor cells from patients with Sézary syndrome do not up-regulate CD95L upon TCR-stimulation and are therefore resistant to AICD. These results show a novel mechanism of AICD resistance in CTCL that could have future therapeutic implications to overcome apoptosis resistance in CTCL patients.

Thermoresponsive polyurethane/siloxane membrane for wound dressing and cell sheet transplantation: In-vitro and in-vivo studies

Energy Technology Data Exchange (ETDEWEB)

Rezapour-Lactoee, Alireza [Department of Tissue Engineering, School of Advanced Medical Technologies, Tehran University of Medical Sciences, 14177-55469 Tehran (Iran, Islamic Republic of); Yeganeh, Hamid, E-mail: h.yeganeh@ippi.ac.ir [Iran Polymer and Petrochemical Institute, P.O. Box: 14965/115, Tehran (Iran, Islamic Republic of); Ostad, Seyed Nasser, E-mail: ostadnas@sina.tums.ac.ir [Department of Tissue Engineering, School of Advanced Medical Technologies, Tehran University of Medical Sciences, 14177-55469 Tehran (Iran, Islamic Republic of); Department of Pharmacology and Toxicology, Faculty of Pharmacy, Tehran University of Medical Sciences, 16 Azar St, Enqelab Sq, Tehran 1417614411 (Iran, Islamic Republic of); Gharibi, Reza [Department of Tissue Engineering, School of Advanced Medical Technologies, Tehran University of Medical Sciences, 14177-55469 Tehran (Iran, Islamic Republic of); Mazaheri, Zohreh [Department of Anatomical Sciences, Faculty of Medical Sciences, Tarbiat Modares University, Tehran (Iran, Islamic Republic of); Ai, Jafar [Department of Tissue Engineering, School of Advanced Medical Technologies, Tehran University of Medical Sciences, 14177-55469 Tehran (Iran, Islamic Republic of)

2016-12-01

Polyurethane/siloxane based wound dressing for transferring fibroblast cell sheet to wounded skin and ability to provide an optimum condition for cellular activity at damaged tissue was prepared in this research. The dressing was made thermoresponsive, via the introduction of a poly(N-isopropyl acrylamide) copolymer into the backbone of dressing. The ability of membrane for adhesion, growth, and proliferation of fibroblast cells was improved via surface modification with gelatin. The optimized dressing exhibited appropriate tensile strength (4.5 MPa) and elongation at break (80%) to protect wound against physical forces. Due to controlled equilibrium water absorption of about 89% and water vapor transmission rate of 2040 g/m{sup 2} day, the dressing could maintain the favorable moist environment over moderate to high exuding wounds. The grown cell sheet on dressing membrane could easily roll up from the surface just with lowering the temperature. The in vivo study of the wound dressed with cell loaded membrane confirmed the accelerated healing and production of tissue with complete re-epithelization, enhanced vascularization, and increased collagen deposition on the damaged area. - Highlights: • Versatile polymerization procedure to prepare wound dressing membranes • Improved cytocompatibility to support growth and proliferation of seeded fibroblasts • Utilizing thermoresponsive characteristic to transfer cell sheet to damaged tissue • Excellent physicomechanical properties of dressings to protect wound bed • Excellent fluid handling to provide moist environment over wounded tissue.

Triethyl orthoformate mediated a novel crosslinking method for the preparation of hydrogels for tissue engineering applications: characterization and in vitro cytocompatibility analysis

Energy Technology Data Exchange (ETDEWEB)

Yar, Muhammad, E-mail: drmyar@ciitlahore.edu.pk [Interdisciplinary Research Center in Biomedical Materials, COMSATS Institute of Information Technology, Lahore 54000 (Pakistan); Shahzad, Sohail [Interdisciplinary Research Center in Biomedical Materials, COMSATS Institute of Information Technology, Lahore 54000 (Pakistan); Department of Chemistry, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan); Siddiqi, Saadat Anwar [Interdisciplinary Research Center in Biomedical Materials, COMSATS Institute of Information Technology, Lahore 54000 (Pakistan); Mahmood, Nasir [Department of Allied Health Sciences and Chemical Pathology, Department of Human Genetics and Molecular Biology, University of Health Sciences, Lahore (Pakistan); Rauf, Abdul [Department of Chemistry, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan); Anwar, Muhammad Sabieh [Department of Physics, Syed Babar Ali School of Science and Engineering, Lahore University of Management Sciences (LUMS), Opposite Sector U, D.H.A., Lahore 54792 (Pakistan); Chaudhry, Aqif Anwar [Interdisciplinary Research Center in Biomedical Materials, COMSATS Institute of Information Technology, Lahore 54000 (Pakistan); Rehman, Ihtesham ur [Interdisciplinary Research Center in Biomedical Materials, COMSATS Institute of Information Technology, Lahore 54000 (Pakistan); Department of Materials Science and Engineering, The Kroto Research Institute, The University of Sheffield, North Campus, Broad Lane, Sheffield S3 7HQ (United Kingdom)

2015-11-01

This paper describes the development of a new crosslinking method for the synthesis of novel hydrogel films from chitosan and PVA for potential use in various biomedical applications. These hydrogel membranes were synthesized by blending different ratios of chitosan (CS) and poly(vinyl alcohol) (PVA) solutions and were crosslinked with 2.5% (w/v) triethyl orthoformate (TEOF) in the presence of 17% (w/v) sulfuric acid. The physical/chemical interactions and the presence of specific functional groups in the synthesized materials were evaluated by Fourier transform infrared (FT-IR) spectroscopy. The morphology, structure and pore size of the materials were investigated by scanning electron microscopy (SEM). Thermal gravimetric analysis (TGA) proved that these crosslinked hydrogel films have good thermal stability which was decreased as the CS ratio was increased. Differential scanning calorimetry (DSC) exhibited that CS and PVA were present in the amorphous form. The solution absorption properties were performed in phosphate buffer saline (PBS) solution of pH 7.4. The 20% PVA–80% CS crosslinked hydrogel films showed a greater degree of solution absorption (183%) as compared to other compositions. The hydrogels with greater CS concentration (60% and 80%) demonstrated relatively more porous structure, better cell viability and proliferation and also revealed good blood clotting ability even after crosslinking. Based on the observed facts these hydrogels can be tailored for their potential utilization in wound healing and skin tissue engineering applications. - Highlights: • A new method for covalently crosslinking of chitosan and PVA. • Triethyl orthoformate (TEOF) a new polymer–polymer crosslinking agent. • Hydrogels displayed a good solution absorption capacity. • Hydrogels demonstrated good cytocompatibility. • Good blood clotting potential was shown by these scaffolds.

Triethyl orthoformate mediated a novel crosslinking method for the preparation of hydrogels for tissue engineering applications: characterization and in vitro cytocompatibility analysis

International Nuclear Information System (INIS)

Yar, Muhammad; Shahzad, Sohail; Siddiqi, Saadat Anwar; Mahmood, Nasir; Rauf, Abdul; Anwar, Muhammad Sabieh; Chaudhry, Aqif Anwar; Rehman, Ihtesham ur

2015-01-01

This paper describes the development of a new crosslinking method for the synthesis of novel hydrogel films from chitosan and PVA for potential use in various biomedical applications. These hydrogel membranes were synthesized by blending different ratios of chitosan (CS) and poly(vinyl alcohol) (PVA) solutions and were crosslinked with 2.5% (w/v) triethyl orthoformate (TEOF) in the presence of 17% (w/v) sulfuric acid. The physical/chemical interactions and the presence of specific functional groups in the synthesized materials were evaluated by Fourier transform infrared (FT-IR) spectroscopy. The morphology, structure and pore size of the materials were investigated by scanning electron microscopy (SEM). Thermal gravimetric analysis (TGA) proved that these crosslinked hydrogel films have good thermal stability which was decreased as the CS ratio was increased. Differential scanning calorimetry (DSC) exhibited that CS and PVA were present in the amorphous form. The solution absorption properties were performed in phosphate buffer saline (PBS) solution of pH 7.4. The 20% PVA–80% CS crosslinked hydrogel films showed a greater degree of solution absorption (183%) as compared to other compositions. The hydrogels with greater CS concentration (60% and 80%) demonstrated relatively more porous structure, better cell viability and proliferation and also revealed good blood clotting ability even after crosslinking. Based on the observed facts these hydrogels can be tailored for their potential utilization in wound healing and skin tissue engineering applications. - Highlights: • A new method for covalently crosslinking of chitosan and PVA. • Triethyl orthoformate (TEOF) a new polymer–polymer crosslinking agent. • Hydrogels displayed a good solution absorption capacity. • Hydrogels demonstrated good cytocompatibility. • Good blood clotting potential was shown by these scaffolds

Now, It's Your Turn: How You Can Take Medicine Safely

Science.gov (United States)

... turn Javascript on. Feature: Taking Medicines Safely Now, It's Your Turn: How You Can Take Medicine Safely ... medicine. The pharmacist has filled the prescription. Now it's up to you to take the medicine safely. ...

Study of Charge Build Up in UCN Storage Cell

Science.gov (United States)

Broering, Mark; Abney, Josh; Swank, Christopher; Filippone, Bradley; Yao, Weijun; Korsch, Wolfgang

2017-09-01

The neutron EDM collaboration at the Spallation Neutron Source(ORNL) is using ultra-cold neutrons in superfluid helium to improve the nEDM limit by about two orders of magnitude. These neutrons will be stored in target cells located in a strong, stable electric field. Local radiation will generate charged particles which may build up on the target cell walls reducing field strength over time. The field changes need to be kept below 1%, making it necessary to study this cell charging behavior, determine its effect on the experiment and find ways to mitigate this. In order to study this cell charging effect, a compact test setup was designed. Using this scaled down model, charged particles are generated by a 137Cs source and the electric field is monitored via the electo-optic Kerr effect. Liquid nitrogen has a much stronger response to electric fields than helium, making it an ideal candidate for first tests. Cell charging effects have been observed in liquid nitrogen. These results along with the experimental technique and progress toward a superfluid helium measurement will also be presented. This research is supported by DOE Grants: DE-FG02-99ER41101, DE-AC05-00OR22725.

Cytocompatibility, mechanical and dissolution properties of high strength boron and iron oxide phosphate glass fibre reinforced bioresorbable composites.

Science.gov (United States)

Sharmin, Nusrat; Hasan, Muhammad S; Parsons, Andrew J; Rudd, Chris D; Ahmed, Ifty

2016-06-01

In this study, Polylactic acid (PLA)/phosphate glass fibres (PGF) composites were prepared by compression moulding. Fibres produced from phosphate based glasses P2O5-CaO-MgO-Na2O (P45B0), P2O5-CaO-MgO-Na2O-B2O3 (P45B5), P2O5-CaO-MgO-Na2O-Fe2O3 (P45Fe3) and P2O5-CaO-MgO-Na2O-B2O3-Fe2O3 (P45B5Fe3) were used to reinforce the bioresorbable polymer PLA. Fibre mechanical properties and degradation rate were investigated, along with the mechanical properties, degradation and cytocompatibility of the composites. Retention of the mechanical properties of the composites was evaluated during degradation in PBS at 37°C for four weeks. The fibre volume fraction in the composite varied from 19 to 23%. The flexural strength values (ranging from 131 to 184MPa) and modulus values (ranging from 9.95 to 12.29GPa) obtained for the composites matched those of cortical bone. The highest flexural strength (184MPa) and modulus (12.29GPa) were observed for the P45B5Fe3 composite. After 28 days of immersion in PBS at 37°C, ~35% of the strength profile was maintained for P45B0 and P45B5 composites, while for P45Fe3 and P45B5Fe3 composites ~40% of the initial strength was maintained. However, the overall wet mass change of P45Fe3 and P45B5Fe3 remained significantly lower than that of the P45B0 and P45B5 composites. The pH profile also revealed that the P45B0 and P45B5 composites degraded quicker, correlating well with the degradation profile. From SEM analysis, it could be seen that after 28 days of degradation, the fibres in the fractured surface of P45B5Fe3 composites remain fairly intact as compared to the other formulations. The in vitro cell culture studies using MG63 cell lines revealed both P45Fe3 and P45B5Fe3 composites maintained and showed higher cell viability as compared to the P45B0 and P45B5 composites. This was attributed to the slower degradation rate of the fibres in P45Fe3 and P45B5Fe3 composites as compared with the fibres in P45B0 and P45B5 composites. Copyright © 2015

Taking up an event: Brand image transfer during the FIFA World Cup

NARCIS (Netherlands)

Neijens, P.; Smit, E.; Moorman, M.

2009-01-01

A real-life study (N = 1299) into brand images during and after the 2006 FIFA World Cup football tournament showed that the event was a good platform for the creation of brand images through ‘take-up’ advertising in which the brand was associated with the event. Exposure level and involvement with

DanDan. Final report. [PEM fuel cells for back-up power and UPS]; DanDan. Slutrapport

Energy Technology Data Exchange (ETDEWEB)

NONE

2012-08-15

The project has provided valuable results for the partners involved, and has resulted in the construction and demonstration of a modular UPS system that can be used with fuel cells. Dantherm Power has provided a 5 kW fuel cell module, based on LT-pem technology, for use in the demonstration and testing facility. The function of the unit is verified by both internal testing and demonstrations from at third parties were it currently is set up to perform tests regarding lifetime. The development of a DC / DC converter, was made. The module has been tested under various conditions, and the development process has resulted in detailed specs of both technique and test process. The module has been tested both in laboratory environment and demonstrated at third parties. The module is part of the systems described in connection with initial test runs - performed at strategic partners - and in connection with the demonstration of the systems both in Japan and in South Africa. The modules are presently in a stage of demonstration, while subjected to substantial service life tests. The purchased reformers are part of the systems used for demonstration in the project and as such they will supply valuable data trough the comprehensive test and verification program initiated. (LN)

Biocorrosion behavior and cell viability of adhesive polymer coated magnesium based alloys for medical implants

Science.gov (United States)

Abdal-hay, Abdalla; Dewidar, Montasser; Lim, Jae Kyoo

2012-11-01

The present study was ultimately aimed to design novel adhesive biodegradable polymer, poly(vinyl acetate) (PVAc), coatings onto Mg based alloys by the dip-coating technique in order to control the degradation rate and enhance the biocompatibility of magnesium alloys. The influence of various solvents on PVAc surface topography and their protection of Mg alloys were dramatically studied in vitro. Electrochemical polarization, degradation, and PVAc film cytocompatibility were also tested. Our results showed that the solvent had a significant effect on coating quality. PVAc/dichloromethane solution showed a porous structure and solution concentration could control the porous size. The coatings prepared using tetrahydrofuran and dimethylformamide solvents are exceptional in their ability to generate porous morphology even at low polymer concentration. In general, the corrosion performance appears to be different on different PVAc-solvent system. Immersion tests illustrated that the porous morphology on PVAc stabilized corrosion rates. A uniform corrosion attack in artificial simulation body fluid was also exhibited. The cytocompatibility of osteoblast cells (MC3T3) revealed high adherence, proliferation, and survival on the porous structure of PVAc coated Mg alloy, which was not observed for the uncoated samples. This novel PVAc coating is a promising candidate for biodegradable implant materials, which might widen the use of Mg based implants.

In Situ Synthesized Silver Nanoclusters for Tracking the Role of Telomerase Activity in the Differentiation of Mesenchymal Stem Cells to Neural Stem Cells.

Science.gov (United States)

Dong, Fangyuan; Feng, Enduo; Zheng, Tingting; Tian, Yang

2018-01-17

Human mesenchymal stem cells (hMSCs) have potential use in cell replacement therapy for central nervous system disorders. However, the factors that impacted the differentiation process are unclear at the present stage because the powerful analytical method is the bottleneck. Herein, a novel strategy was developed for self-imaging and biosensing of telomerase activity in stem cells, using in situ biosynthesized silver nanoclusters (AgNCs) full of C bases. The present AgNCs possess synthetic convenience, long-time stability, and cytocompatibility. The weak fluorescence of these AgNCs is quickly turned on when approaching telomerase because of the strong interaction between C bases on AgNCs and G bases in telomerase, resulting in telomerase-dependent fluorescent signals. The developed method demonstrated high sensitivity and selectivity and broad dynamic linear range with a low detection limit. Using this powerful tool, it was first discovered that telomerase activity plays important roles in the proliferation of hMSCs and neural stem cells (NSCs) as well as during the differentiation processes from hMSCs to NSCs.

Tubular Scaffold with Shape Recovery Effect for Cell Guide Applications

Directory of Open Access Journals (Sweden)

Kazi M. Zakir Hossain

2015-07-01

Full Text Available Tubular scaffolds with aligned polylactic acid (PLA fibres were fabricated for cell guide applications by immersing rolled PLA fibre mats into a polyvinyl acetate (PVAc solution to bind the mats. The PVAc solution was also mixed with up to 30 wt % β-tricalcium phosphate (β-TCP content. Cross-sectional images of the scaffold materials obtained via scanning electron microscopy (SEM revealed the aligned fibre morphology along with a significant number of voids in between the bundles of fibres. The addition of β-TCP into the scaffolds played an important role in increasing the void content from 17.1% to 25.3% for the 30 wt % β-TCP loading, which was measured via micro-CT (µCT analysis. Furthermore, µCT analyses revealed the distribution of aggregated β-TCP particles in between the various PLA fibre layers of the scaffold. The compressive modulus properties of the scaffolds increased from 66 MPa to 83 MPa and the compressive strength properties decreased from 67 MPa to 41 MPa for the 30 wt % β-TCP content scaffold. The scaffolds produced were observed to change into a soft and flexible form which demonstrated shape recovery properties after immersion in phosphate buffered saline (PBS media at 37 °C for 24 h. The cytocompatibility studies (using MG-63 human osteosarcoma cell line revealed preferential cell proliferation along the longitudinal direction of the fibres as compared to the control tissue culture plastic. The manufacturing process highlighted above reveals a simple process for inducing controlled cell alignment and varying porosity features within tubular scaffolds for potential tissue engineering applications.

Heavy-water (D2O) take-up-induced lattice expansion in the high-temperature proton conductor Ba3Ca1.18Nb1.82O9-δ

International Nuclear Information System (INIS)

Papathanassopoulos, K.; Wenzl, H.; Schober, T.

1997-01-01

Dimensional changes of the high-temperature proton conductor Ba 3 Ca 1.18 Nb 1.82 O 9-δ , when exposed to D 2 O vapor, were investigated using length-change and precision density measurements. Such information is essential for possible applications of proton conductors in solid oxide fuel cells and humidity and hydrogen sensors. A linear increase of the sample lengths with increases in the deuterium content was observed. Comparison of the present D 2 O data with those that were previously obtained for H 2 O showed that there was a small isotope effect in the lattice expansion. The fact that the length-change-versus-hydrogen-isotope-concentration curves were almost isotope independent supported the validity of the take-up reaction H 2 O(g) + V sm-bulletsm-bullet O + O x O right-reversible 2OH sm-bullet O , where V O is the vacancies in the oxygen sublattice and OH sm-bullet O is the proton that are embedded in the electron cloud of an oxygen atom. In regard to the latter equation, it was found that small islands of silver, palladium, nickel, and platinum act as catalytic promoters of the reaction and lead, for given heavy-water-steam exposure conditions, to an increase of water absorption of up to 100%, when compared with samples without the catalytic surface layers

'Hearts and bones': the ups and downs of 'plasticity' in stem cell biology.

Science.gov (United States)

Bonfanti, Paola; Barrandon, Yann; Cossu, Giulio

2012-05-01

More than a decade ago, 'plasticity' suddenly became a 'fashionable' topic with overemphasized implications for regenerative medicine. The concept of 'plasticity' is supported by old transplantation work, at least for embryonic cells, and metaplasia is a classic example of plasticity observed in patients. Nevertheless, the publication of a series of papers showing rare conversion of a given cell type into another unrelated cell raised the possibility of using any unaffected tissue to create at will new cells to replace a different failing tissue or organ. This resulted in disingenuous interpretations and a reason not to fund anymore research on embryonic stem cells (ESc). Moreover, many papers on plasticity were difficult to reproduce and thus questioned; raising issues about plasticity as a technical artefact or a consequence of rare spontaneous cells fusion. More recently, reprogramming adult differentiated cells to a pluripotent state (iPS) became possible, and later, one type of differentiated cell could be directly reprogrammed into another (e.g. fibroblasts into neurons) without reverting to pluripotency. Although the latter results from different and more robust experimental protocols, these phenomena also exemplify 'plasticity'. In this review, we want to place 'plasticity' in a historical perspective still taking into account ethical and political implications. Copyright © 2012 EMBO Molecular Medicine.

In vitro response of pre-osteoblastic cells to laser microgrooved PEEK

International Nuclear Information System (INIS)

Cordero, D; López-Álvarez, M; Rodríguez-Valencia, C; Serra, J; Chiussi, S; González, P

2013-01-01

Polyetheretherketone (PEEK) is currently being used in implants as an alternative to titanium, due to its mechanical properties, cytocompatibility and inertness. Several studies have demonstrated that certain patterning on the implants promotes the oriented cell growth of osteoblasts, favouring the formation of bone tissue. This patterning improves the implant's osteointegration in the bone and its mechanical stability. Therefore, the objective of this work is to micro-structure PEEK by laser radiation and to carry out an exhaustive study of the orientation of pre-osteoblast cells that grow on this material. Parallel microgrooves were obtained using an ArF excimer laser coupled with a mask projection unit with distances of 25, 50, 75 and 100 µm between grooves. The cell growth on these PEEK surfaces was studied, in order to compare the effect of different distances between grooves on the biological response of MC3T3-E1 pre-osteoblastic cells. Preferential cell orientation was observed for all studied distances, which was more pronounced in the 25 and 50 µm ones. (paper)

Understanding the build-up of a technological innovation system around hydrogen and fuel cell technologies

NARCIS (Netherlands)

Suurs, R.A.A.; Hekkert, M.P.; Smits, R.E.H.M.

2009-01-01

This study provides insight into the development of hydrogen and fuel cell technologies in the Netherlands (1980-2007). This is done by applying a Technological Innovation System (TIS) approach. This approach takes the perspective that a technology is shaped by a surrounding network of actors,

CARACTERIZAÇÃO E AVALIAÇÃO IN VITRO DE NANOCOMPÓSITOS DE POLI (L-ÁCIDO LÁTICO E NANOTUBOS DE CARBONO DE PAREDES MÚLTIPLAS PURIFICADOS

Directory of Open Access Journals (Sweden)

Claudenete Vieira Leal

2015-11-01

Full Text Available Carbon nanotubes (CNT have been studied for biomedical applications due to their unique properties. However, pristine CNT have structural features and impurities that can cause toxicity to biological systems. In this work, we describe a method to purify multiwalled carbon nanotubes (MWCNT by chemical modification and subsequent attachment of hydroxyl and carboxyl groups to improve dispersion and to decrease toxic effects. Nanocomposites from poly (L-lactic acid (PLLA and nanotubes were produced by the solvent casting method and characterized and evaluated for cytocompatibility with Vero cells. The nanocomposite interactions with Vero cells demonstrated that the cells were able to adhere and sustain proliferation and showed favorable cytocompatibility. In vitro studies also revealed an increase in fibroblast cell viability in the nanocomposites, compared with neat PLLA.

Setting up a Bioluminescence Resonance Energy Transfer high throughput screening assay to search for protein/protein interaction inhibitors in mammalian cells.

Directory of Open Access Journals (Sweden)

Cyril eCouturier

2012-09-01

Full Text Available Each step of the cell life and its response or adaptation to its environment are mediated by a network of protein/protein interactions termed interactome. Our knowledge of this network keeps growing due to the development of sensitive techniques devoted to study these interactions. The bioluminescence resonance energy transfer (BRET technique was primarily developed to allow the dynamic monitoring of protein-protein interactions in living cells, and has widely been used to study receptor activation by intra- or extra-molecular conformational changes within receptors and activated complexes in mammal cells. Some interactions are described as crucial in human pathological processes, and a new class of drugs targeting them has recently emerged. The BRET method is well suited to identify inhibitors of protein-protein interactions and here is described why and how to set up and optimize a High Throughput Screening assay based on BRET to search for such inhibitory compounds. The different parameters to take into account when developing such BRET assays in mammal cells are reviewed to give general guidelines: considerations on the targeted interaction, choice of BRET version, inducibility of the interaction, kinetic of the monitored interaction, and of the BRET reading, influence substrate concentration, number of cells and medium composition used on the Z’ factor, and expected interferences for colored or fluorescent compounds.

Biophysical response of living cells to boron nitride nanoparticles: uptake mechanism and bio-mechanical characterization

Energy Technology Data Exchange (ETDEWEB)

Rasel, Md. Alim Iftekhar; Li, Tong; Nguyen, Trung Dung; Singh, Sanjleena [Queensland University of Technology (QUT), School of Chemistry, Physics and Mechanical Engineering (Australia); Zhou, Yinghong; Xiao, Yin [Queensland University of Technology (QUT), Institute of Health and Biomedical Innovation (Australia); Gu, YuanTong, E-mail: yuantong.gu@qut.edu.au [Queensland University of Technology (QUT), School of Chemistry, Physics and Mechanical Engineering (Australia)

2015-11-15

Boron nitride nanomaterials have attracted significant interest due to their superior chemical and physical properties. Despite these novel properties, investigation on the interaction between boron nitride nanoparticle (BN NP) and living systems has been limited. In this study, BN NP (100–250 nm) is assessed as a promising biomaterial for medical applications. The toxicity of BN NP is evaluated by assessing the cells behaviours both biologically (MTT assay, ROS detection etc.) and physically (atomic force microscopy). The uptake mechanism of BN NP is studied by analysing the alternations in cellular morphology based on cell imaging techniques. The results demonstrate in vitro cytocompatibility of BN NP with immense potential for use as an effective nanoparticle for various bio-medical applications.

Calcification of MC3T3-E1 cells on titanium and zirconium.

Science.gov (United States)

Umezawa, Takayuki; Chen, Peng; Tsutsumi, Yusuke; Doi, Hisashi; Ashida, Maki; Suzuki, Shoichi; Moriyama, Keiji; Hanawa, Takao

2015-01-01

To confirm similarity of hard tissue compatibility between titanium and zirconium, calcification of MC3T3-E1 cells on titanium and zirconium was evaluated in this study. Mirror-polished titanium (Ti) and zirconium (Zr) disks and zirconium-sputter deposited titanium (Zr/Ti) were employed in this study. The surface of specimens were characterized using scanning electron microscopy and X-ray diffraction. Then, the cellular proliferation, differentiation and calcification of MC3T3-E1 cells on specimens were investigated. The surface of Zr/Ti was much smoother and cleaner than those of Ti and Zr. The proliferation of the cell was the same among three specimens, while the differentiation and calcification on Zr/Ti were faster than those on Ti and Zr. Therefore, Ti and Zr showed the identical hard tissue compatibility according to the evaluation with MC3T3-E1 cells. Sputter deposition may improve cytocompatibility.

Fabrication of micropatterned alginate-gelatin and k-carrageenan hydrogels of defined shapes using simple wax mould method as a platform for stem cell/induced Pluripotent Stem Cells (iPSC) culture.

Science.gov (United States)

Vignesh, S; Gopalakrishnan, Aswathi; M R, Poorna; Nair, Shantikumar V; Jayakumar, R; Mony, Ullas

2018-06-01

Micropatterning techniques involve soft lithography, which is laborious, expensive and restricted to a narrow spectrum of biomaterials. In this work we report, first time employment of patterned wax moulds for generation of micropatterned alginate-gelatin and κ-carrageenan (κ-CRG) hydrogel systems by a novel, simple and cost effective method. We generated and characterized uniform and reproducible micropatterned hydrogels of varying sizes and shapes such as square projections, square grooves, and circular grids and crisscrossed hillocks. The rheological analysis showed that κ-carrageenan hydrogels had higher gel strength when compared to alginate-gelatin hydrogels. Human Mesenchymal stem cells (hMSCs) and Human Induced Pluripotent Stem Cells (hiPSCs) were found to be cytocompatible with these hydrogels. This micropatterned hydrogel system may have potential application in tissue engineering and also in understanding the basic biology behind the stem cell/iPSC fate. Copyright © 2018 Elsevier B.V. All rights reserved.

In vitro study of nanostructured diopside coating on Mg alloy orthopedic implants

International Nuclear Information System (INIS)

Razavi, Mehdi; Fathi, Mohammadhossein; Savabi, Omid; Vashaee, Daryoosh; Tayebi, Lobat

2014-01-01

The high corrosion rate of Mg alloys has hindered their application in various areas, particularly for orthopedic applications. In order to decrease the corrosion rate and to improve the bioactivity, mechanical stability and cytocompatibility of the Mg alloy, nanostructured diopside (CaMgSi 2 O 6 ) has been coated on AZ91 Mg alloy using a combined micro arc oxidation (MAO) and electrophoretic deposition (EPD) method. The crystalline structure, the morphology and the composition of the samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Electrochemical corrosion test, immersion test, and compression test were used to evaluate the corrosion resistance, the in vitro bioactivity and the mechanical stability of the samples, respectively. The cytocompatibility of the samples was tested by the cell viability and the cell attachment of L-929 cells. The results confirmed that the diopside coating not only slows down the corrosion rate, but also enhances the in vitro bioactivity, mechanical stability and cytocompatibility of AZ91 Mg alloy. Therefore, Mg alloy coated with nanostructured diopside offers a promising approach for biodegradable bone implants. - Highlights: • The diopside coating was applied on Mg alloy using the combined MAO and EPD methods. • The corrosion resistance of the diopside coated Mg alloy was noticeably improved. • The in vitro bioactivity of the diopside coated Mg alloy was considerably increased. • The mechanical stability of biodegradable Mg alloy was enhanced by diopside coating. • The cytocompatibility of the Mg alloy was improved employing diopside coating

In vitro study of nanostructured diopside coating on Mg alloy orthopedic implants

Energy Technology Data Exchange (ETDEWEB)

Razavi, Mehdi, E-mail: mehdi.razavi@okstate.edu [Biomaterials Research Group, Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Torabinejad Dental Research Center, School of Dentistry, Isfahan University of Medical Sciences, Isfahan 81746-73461 (Iran, Islamic Republic of); School of Materials Science and Engineering, Helmerich Advanced Technology Research Center, Oklahoma State University, Tulsa, OK 74106 (United States); School of Electrical and Computer Engineering, Helmerich Advanced Technology Research Center, Oklahoma State University, Tulsa, OK 74106 (United States); Fathi, Mohammadhossein [Biomaterials Research Group, Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Dental Materials Research Center, Isfahan University of Medical Sciences, Isfahan (Iran, Islamic Republic of); Savabi, Omid [Torabinejad Dental Research Center, School of Dentistry, Isfahan University of Medical Sciences, Isfahan 81746-73461 (Iran, Islamic Republic of); Vashaee, Daryoosh [School of Electrical and Computer Engineering, Helmerich Advanced Technology Research Center, Oklahoma State University, Tulsa, OK 74106 (United States); Tayebi, Lobat, E-mail: lobat.tayebi@okstate.edu [School of Materials Science and Engineering, Helmerich Advanced Technology Research Center, Oklahoma State University, Tulsa, OK 74106 (United States); School of Chemical Engineering, Oklahoma State University, Stillwater, OK 74078 (United States)

2014-08-01

The high corrosion rate of Mg alloys has hindered their application in various areas, particularly for orthopedic applications. In order to decrease the corrosion rate and to improve the bioactivity, mechanical stability and cytocompatibility of the Mg alloy, nanostructured diopside (CaMgSi{sub 2}O{sub 6}) has been coated on AZ91 Mg alloy using a combined micro arc oxidation (MAO) and electrophoretic deposition (EPD) method. The crystalline structure, the morphology and the composition of the samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Electrochemical corrosion test, immersion test, and compression test were used to evaluate the corrosion resistance, the in vitro bioactivity and the mechanical stability of the samples, respectively. The cytocompatibility of the samples was tested by the cell viability and the cell attachment of L-929 cells. The results confirmed that the diopside coating not only slows down the corrosion rate, but also enhances the in vitro bioactivity, mechanical stability and cytocompatibility of AZ91 Mg alloy. Therefore, Mg alloy coated with nanostructured diopside offers a promising approach for biodegradable bone implants. - Highlights: • The diopside coating was applied on Mg alloy using the combined MAO and EPD methods. • The corrosion resistance of the diopside coated Mg alloy was noticeably improved. • The in vitro bioactivity of the diopside coated Mg alloy was considerably increased. • The mechanical stability of biodegradable Mg alloy was enhanced by diopside coating. • The cytocompatibility of the Mg alloy was improved employing diopside coating.

Demethoxycurcumin inhibited human epithelia ovarian cancer cells' growth via up-regulating miR-551a.

Science.gov (United States)

Du, Zhenhua; Sha, Xianqun

2017-03-01

Curcumin is a natural agent that has ability to dampen tumor cells' growth. However, the natural form of curcumin is prone to degrade and unstable in vitro. Here, we demonstrated that demethoxycurcumin (a curcumin-related demethoxy compound) could inhibit cell proliferation and induce apoptosis of ovarian cancer cells. Moreover, IRS2/PI3K/Akt axis was inactivated in cells treated with demethoxycurcumin. Quantitative real-time reverse transcription polymerase chain reaction demonstrated that miR-551a was down-regulated in ovarian cancer tissues and ovarian cancer cell lines. Over-expression of miR-551a inhibited cell proliferation and induced apoptosis of ovarian cancer cells, whereas down-regulation of miR-551a exerted the opposite function. Luciferase assays confirmed that there was a binding site of miR-551a in IRS2, and we found that miR-551a exerted tumor-suppressive function by targeting IRS2 in ovarian cancer cells. Remarkably, miR-551a was up-regulated in the cells treated with demethoxycurcumin, and demethoxycurcumin suppressed IRS2 by restoration of miR-551a. In conclusion, demethoxycurcumin hindered ovarian cancer cells' malignant progress via up-regulating miR-551a.

Near-infrared fluorescent aza-BODIPY dye-loaded biodegradable polymeric nanoparticles for optical cancer imaging

International Nuclear Information System (INIS)

Hamon, Casey L.; Dorsey, Christopher L.; Özel, Tuğba; Barnes, Eugenia M.; Hudnall, Todd W.; Betancourt, Tania

2016-01-01

Nanoparticles are being readily investigated as carriers for the delivery of imaging and therapeutic agents for the detection, monitoring, and treatment of cancer and other diseases. In the present work, the preparation of biodegradable polymeric nanoparticles loaded with a near-infrared fluorescent aza-boron dipyrromethene (NIR-BODIPY) derivative, and their use as contrast agents for optical imaging in cancer are described. Nanoparticles were prepared by nanoprecipitation of amphiphilic block copolymers of poly(lactic acid) and poly(ethylene glycol). The size, morphology, dye loading, spectral properties, quantum yield, cytocompatibility, and in vitro NIR imaging potential of the nanoparticles in breast and ovarian cancer cells were evaluated. Spherical nanoparticles of 30–70 nm in diameter were loaded with 0.73 w/w% BODIPY derivative. At this loading, the dye presented a fluorescence quantum yield in the same order of magnitude as in solution. Nanoparticle suspensions at concentrations up to 580 μg/mL were cytocompatible to breast (MDA-MB-231) and ovarian (SKOV-3 and Caov-3) cancer cells after a four-hour incubation period. Fluorescence microscopy images demonstrated the ability of the nanoparticles to act as imaging agents in all three cell lines in as little as 1 hour. The results shown indicate the potential of these NIR-BODIPY-loaded nanoparticles as contrast agents for near-infrared optical imaging in cancer.Graphical abstract

Near-infrared fluorescent aza-BODIPY dye-loaded biodegradable polymeric nanoparticles for optical cancer imaging

Energy Technology Data Exchange (ETDEWEB)

Hamon, Casey L.; Dorsey, Christopher L. [Texas State University, Department of Chemistry and Biochemistry (United States); Özel, Tuğba [Texas State University, Materials Science, Engineering, and Commercialization Program (United States); Barnes, Eugenia M.; Hudnall, Todd W.; Betancourt, Tania, E-mail: tb26@txstate.edu [Texas State University, Department of Chemistry and Biochemistry (United States)

2016-07-15

Nanoparticles are being readily investigated as carriers for the delivery of imaging and therapeutic agents for the detection, monitoring, and treatment of cancer and other diseases. In the present work, the preparation of biodegradable polymeric nanoparticles loaded with a near-infrared fluorescent aza-boron dipyrromethene (NIR-BODIPY) derivative, and their use as contrast agents for optical imaging in cancer are described. Nanoparticles were prepared by nanoprecipitation of amphiphilic block copolymers of poly(lactic acid) and poly(ethylene glycol). The size, morphology, dye loading, spectral properties, quantum yield, cytocompatibility, and in vitro NIR imaging potential of the nanoparticles in breast and ovarian cancer cells were evaluated. Spherical nanoparticles of 30–70 nm in diameter were loaded with 0.73 w/w% BODIPY derivative. At this loading, the dye presented a fluorescence quantum yield in the same order of magnitude as in solution. Nanoparticle suspensions at concentrations up to 580 μg/mL were cytocompatible to breast (MDA-MB-231) and ovarian (SKOV-3 and Caov-3) cancer cells after a four-hour incubation period. Fluorescence microscopy images demonstrated the ability of the nanoparticles to act as imaging agents in all three cell lines in as little as 1 hour. The results shown indicate the potential of these NIR-BODIPY-loaded nanoparticles as contrast agents for near-infrared optical imaging in cancer.Graphical abstract.

Gas Permeation, Mechanical Behavior and Cytocompatibility of Ultrathin Pure and Doped Diamond-Like Carbon and Silicon Oxide Films

Directory of Open Access Journals (Sweden)

Juergen M. Lackner

2013-12-01

Full Text Available Protective ultra-thin barrier films gather increasing economic interest for controlling permeation and diffusion from the biological surrounding in implanted sensor and electronic devices in future medicine. Thus, the aim of this work was a benchmarking of the mechanical oxygen permeation barrier, cytocompatibility, and microbiological properties of inorganic ~25 nm thin films, deposited by vacuum deposition techniques on 50 µm thin polyetheretherketone (PEEK foils. Plasma-activated chemical vapor deposition (direct deposition from an ion source was applied to deposit pure and nitrogen doped diamond-like carbon films, while physical vapor deposition (magnetron sputtering in pulsed DC mode was used for the formation of silicon as well as titanium doped diamond-like carbon films. Silicon oxide films were deposited by radio frequency magnetron sputtering. The results indicate a strong influence of nanoporosity on the oxygen transmission rate for all coating types, while the low content of microporosity (particulates, etc. is shown to be of lesser importance. Due to the low thickness of the foil substrates, being easily bent, the toughness as a measure of tendency to film fracture together with the elasticity index of the thin films influence the oxygen barrier. All investigated coatings are non-pyrogenic, cause no cytotoxic effects and do not influence bacterial growth.

Glucose transport machinery reconstituted in cell models.

Science.gov (United States)

Hansen, Jesper S; Elbing, Karin; Thompson, James R; Malmstadt, Noah; Lindkvist-Petersson, Karin

2015-02-11

Here we demonstrate the production of a functioning cell model by formation of giant vesicles reconstituted with the GLUT1 glucose transporter and a glucose oxidase and hydrogen peroxidase linked fluorescent reporter internally. Hence, a simplified artificial cell is formed that is able to take up glucose and process it.

Oral squamous cell carcinoma and a clinically negative neck : the value of follow-up

NARCIS (Netherlands)

Wensing, Bart M; Merkx, Matthias A W; Krabbe, Paul F M; Marres, Henri A M; Van den Hoogen, Frank J A

2011-01-01

BACKGROUND: In squamous cell carcinoma of the oral cavity (SCCOC), regular follow-up comprises 5 years of prescheduled visits, irrespective of tumor stage/classification and/or treatment. We analyzed our standard treatment and follow-up protocol in patients with a preoperative clinically negative

Hypoxia-elicited impairment of cell wall integrity, glycosylation precursor synthesis, and growth in scaled-up high-cell density fed-batch cultures of Saccharomyces cerevisiae.

Science.gov (United States)

Aon, Juan C; Sun, Jianxin; Leighton, Julie M; Appelbaum, Edward R

2016-08-15

In this study we examine the integrity of the cell wall during scale up of a yeast fermentation process from laboratory scale (10 L) to industrial scale (10,000 L). In a previous study we observed a clear difference in the volume fraction occupied by yeast cells as revealed by wet cell weight (WCW) measurements between these scales. That study also included metabolite analysis which suggested hypoxia during scale up. Here we hypothesize that hypoxia weakens the yeast cell wall during the scale up, leading to changes in cell permeability, and/or cell mechanical resistance, which in turn may lead to the observed difference in WCW. We tested the cell wall integrity by probing the cell wall sensitivity to Zymolyase. Also exometabolomics data showed changes in supply of precursors for the glycosylation pathway. The results show a more sensitive cell wall later in the production process at industrial scale, while the sensitivity at early time points was similar at both scales. We also report exometabolomics data, in particular a link with the protein glycosylation pathway. Significantly lower levels of Man6P and progressively higher GDP-mannose indicated partially impaired incorporation of this sugar nucleotide during co- or post-translational protein glycosylation pathways at the 10,000 L compared to the 10 L scale. This impairment in glycosylation would be expected to affect cell wall integrity. Although cell viability from samples obtained at both scales were similar, cells harvested from 10 L bioreactors were able to re-initiate growth faster in fresh shake flask media than those harvested from the industrial scale. The results obtained help explain the WCW differences observed at both scales by hypoxia-triggered weakening of the yeast cell wall during the scale up.

Cobalt-Doped Brushite Cement: Preparation, Characterization, and In Vitro Interaction with Osteosarcoma Cells

Science.gov (United States)

Cummings, Haley; Han, Weiguo; Vahabzadeh, Sahar; Elsawa, Sherine F.

2017-08-01

Brushite cement (BrC) is being widely used in bone and dental tissue engineering application because of its significant biocompatibility, bioresorbability, and moldability. Here, we have reported the effects of cobalt (Co) and its concentration on physical and biological properties of BrC. Our results show that Co addition stabilizes the tricalcium phosphate structure and decreases the amount of BrC phase in the final product. The in vitro interaction of samples with osteosarcoma MG-63 cells proved the cytocompatibility of all compositions in both normoxic and hypoxic conditions. Although the cell viability increased under hypoxia, the change was insignificant compared with normoxic conditions. Our data show that Co addition reduced hypoxia inducible factor-1α and glioma-associated oncogene family zinc finger 2 expression in MG-63, suggesting Co may provide the benefit of reducing the effects of hypoxia on gene expression in the osteosarcoma cell line.

For whom does social comparison induce risk-taking?

NARCIS (Netherlands)

Dijk, O.

2017-01-01

A ‘bonus culture’ among financial traders has been blamed for the excessive risk-taking in the run-up to the latest financial crisis. I show that when individuals are more social gain seeking than social loss averse (i.e. gloating is stronger than envy), social comparison predicts more risk-taking

Axl receptor tyrosine kinase is up-regulated in metformin resistant prostate cancer cells

Science.gov (United States)

Bansal, Nitu; Mishra, Prasun J.; Stein, Mark; DiPaola, Robert S.; Bertino, Joseph R.

2015-01-01

Recent epidemiological studies showed that metformin, a widely used anti-diabetic drug might prevent certain cancers. Metformin also has an anti-proliferative effect in preclinical studies of both hematologic malignancies as well as solid cancers and clinical studies testing metformin as an anti-cancer drug are in progress. However, all cancer types do not respond to metformin with the same effectiveness or acquire resistance. To understand the mechanism of acquired resistance and possibly its mechanism of action as an anti-proliferative agent, we developed metformin resistant LNCaP prostate cancer cells. Metformin resistant LNCaP cells had an increased proliferation rate, increased migration and invasion ability as compared to the parental cells, and expressed markers of epithelial-mesenchymal transition (EMT). A detailed gene expression microarray comparing the resistant cells to the wild type cells revealed that Edil2, Ereg, Axl, Anax2, CD44 and Anax3 were the top up-regulated genes and calbindin 2 and TPTE (transmembrane phosphatase with tensin homology) and IGF1R were down regulated. We focused on Axl, a receptor tyrosine kinase that has been shown to be up regulated in several drug resistance cancers. Here, we show that the metformin resistant cell line as well as castrate resistant cell lines that over express Axl were more resistant to metformin, as well as to taxotere compared to androgen sensitive LNCaP and CWR22 cells that do not overexpress Axl. Forced overexpression of Axl in LNCaP cells decreased metformin and taxotere sensitivity and knockdown of Axl in resistant cells increased sensitivity to these drugs. Inhibition of Axl activity by R428, a small molecule Axl kinase inhibitor, sensitized metformin resistant cells that overexpressed Axl to metformin. Inhibitors of Axl may enhance tumor responses to metformin and other chemotherapy in cancers that over express Axl. PMID:26036314

Lopinavir up-regulates expression of the antiviral protein ribonuclease L in human papillomavirus-positive cervical carcinoma cells.

Science.gov (United States)

Batman, Gavin; Oliver, Anthony W; Zehbe, Ingeborg; Richard, Christina; Hampson, Lynne; Hampson, Ian N

2011-01-01

We have previously shown that the HIV protease inhibitor lopinavir has selective toxicity against human papillomavirus (HPV)-positive cervical carcinoma cells via an unknown mechanism. SiHa cervical carcinoma cells were stably transfected with the proteasome sensor vector pZsProSensor-1 to confirm lopinavir inhibits the proteasome in these cells. The Panorama Xpress profiler 725 antibody array was then used to analyse specific changes in protein expression in lopinavir-treated versus control untreated SiHa cells followed by PCR and western blotting. Colorimetric growth assays of lopinavir-treated E6/E7 immortalised versus control human keratinocytes were performed. Targeted small interfering RNA gene silencing followed by growth assay comparison of lopinavir-treated/untreated SiHa cells was also used. Lopinavir induced an increase in the fluorescence of pZsProSensor-1 transfected SiHa cells, indicative of proteasomal inhibition. Ribonuclease L (RNASEL) protein was shown to be up-regulated in lopinavir-treated SiHa cells, which was confirmed by PCR and western blot. Targeted silencing of RNASEL reduced the sensitivity of SiHa cells to lopinavir. Selective toxicity against E6/E7 immortalised keratinocytes versus control cells was also seen with lopinavir and was associated with up-regulated RNASEL expression. These data are consistent with the toxicity of lopinavir against HPV-positive cervical carcinoma cells being related to its ability to block viral proteasome activation and induce an up-regulation of the antiviral protein RNASEL. This is supported by the drug's selective toxicity and up-regulation of RNASEL in E6/E7 immortalised keratinocytes combined with the increased resistance to lopinavir observed in SiHa cells following silencing of RNASEL gene expression.

Fabrication of fluorescent silica nanoparticles with aggregation-induced emission luminogens for cell imaging.

Science.gov (United States)

Chen, Sijie; Lam, Jacky W Y; Tang, Ben Zhong

2013-01-01

Fluorescence-based techniques have found wide applications in life science. Among various luminogenic materials, fluorescent nanoparticles have attracted much attention due to their fabulous emission properties and potential applications as sensors. Here, we describe the fabrication of fluorescent silica nanoparticles (FSNPs) containing aggregation-induced emission (AIE) luminogens. By employing surfactant-free sol-gel reaction, FSNPs with uniform size and high surface charge and colloidal stability are generated. The FSNPs emit strong light upon photoexcitation, due to the AIE characteristic of the silole -aggregates in the hybrid nanoparticles. The FSNPs are cytocompatible and can be utilized as fluorescent visualizer for intracellular imaging for HeLa cells.

Up-regulation of microRNA-1290 impairs cytokinesis and affects the reprogramming of colon cancer cells.

Science.gov (United States)

Wu, Jia; Ji, Xiaowei; Zhu, Linlin; Jiang, Qiaoli; Wen, Zhenzhen; Xu, Song; Shao, Wei; Cai, Jianting; Du, Qin; Zhu, Yongliang; Mao, Jianshan

2013-02-28

Abnormal cytokinesis increases the possibility of nuclear fusion in tumor cells. However, the role of microRNAs (miRNAs) in abnormal cytokinesis is unclear. Here, we found that miR-1290 was significantly up-regulated in clinical colon cancer tissues. Up-regulation of miR-1290 postponed cytokinesis and led to the formation of multinucleated cells. KIF13B was a target of miR-1290 that was involved in aberrant cytokinesis. Furthermore, enforced expression of miR-1290 activated the Wnt pathway and increased the reprogramming-related transcript factors c-Myc and Nanog. Our results suggest that up-regulation of miR-1290 in colon cancer cells impaired cytokinesis and affected reprogramming. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Publication Of Administrative Circulars: No. 4 (Rev. 4) – Unemployment Insurance Scheme No. 30 (Rev. 2) – Financial Benefits on Taking Up Appointment and on Termination of Contract

CERN Multimedia

HR Department

2008-01-01

Administrative Circular No. 4 (Rev. 4) – Unemployment insurance scheme Administrative Circular No. 4 (Rev. 4) – "Unemployment insurance scheme", approved following discussion in the Standing Concertation Committee meetings of 28 August 2007 and 27 February 2008, is now available on the intranet site of the Human Resources Department. It cancels and replaces Administrative Circular No. 4 (Rev. 3) – "Unemployment insurance" of October 1993. Copies will shortly be available in Departmental secretariats. Human Resources Department Tel. 78003 Administrative Circular No. 30 (Rev. 2) – Financial benefits on taking up appointment and termination of contract Administrative Circular No. 30 (Rev. 2) – "Financial benefits on taking up appointment and termination of contract", approved following discussion in the Standing Concertation Committee meetings of 28 August 2007 and 27 February 2008, is now available on the intranet site of the Human Resources De...

Publication Of Administrative Circulars: No. 4 (Rev. 4) – Unemployment Insurance Scheme No. 30 (Rev. 2) – Financial Benefits on Taking Up Appointment and on Termination of Contract

CERN Document Server

HR Department

2008-01-01

Administrative Circular No. 4 (Rev. 4) – Unemployment insurance scheme Administrative Circular No. 4 (Rev. 4) – "Unemployment insurance scheme", approved following discussion at the Standing Concertation Committee meetings of 28 August 2007 and 27 February 2008, is now available on the intranet site of the Human Resources Department. It cancels and replaces Administrative Circular No. 4 (Rev. 3) – "Unemployment insurance" of October 1993. Copies will shortly be available in Departmental secretariats. Human Resources Department Tel. 78003 Administrative Circular No. 30 (Rev. 2) – Financial benefits on taking up appointment and termination of contract Administrative Circular No. 30 (Rev. 2) – "Financial benefits on taking up appointment and termination of contract", approved following discussion at the Standing Concertation Committee meetings of 28 August 2007 and 27 February 2008, is now available on the intranet site of the Human Resources De...

Biofluidic Transport and Molecular Recognition in Polymer Microdevices

National Research Council Canada - National Science Library

Davis, Robert H; Anseth, Kristi S; Bowman, Christopher N

2005-01-01

.... Key accomplishments include specific cell adhesion and cytocompatibility demonstrated with grafted surfaces, a fluid-responsive polymer micropump integrated on a device and characterized, a porous...

CELLFS: TAKING THE "DMA" OUT OF CELL PROGRAMMING

Energy Technology Data Exchange (ETDEWEB)

IONKOV, LATCHESAR A. [Los Alamos National Laboratory; MIRTCHOVSKI, ANDREY A. [Los Alamos National Laboratory; NYRHINEN, AKI M. [Los Alamos National Laboratory

2007-01-09

In this paper we present a new programming model for the Cell BE architecture of scalar multiprocessors. They call this programming model CellFS. CellFS aims at simplifying the task of managing I/O between the local store of the processing units and main memory. The CellFS support library provides the means for transferring data via simple file I/O operations between the PPU and the SPU.

Evaluation of mechanism of cold atmospheric pressure plasma assisted polymerization of acrylic acid on low density polyethylene (LDPE) film surfaces: Influence of various gaseous plasma pretreatment

Science.gov (United States)

Ramkumar, M. C.; Pandiyaraj, K. Navaneetha; Arun Kumar, A.; Padmanabhan, P. V. A.; Uday Kumar, S.; Gopinath, P.; Bendavid, A.; Cools, P.; De Geyter, N.; Morent, R.; Deshmukh, R. R.

2018-05-01

Owing to its exceptional physiochemical properties, low density poly ethylene (LDPE) has wide range of tissue engineering applications. Conversely, its inadequate surface properties make LDPE an ineffectual candidate for cell compatible applications. Consequently, plasma-assisted polymerization with a selected precursor is a good choice for enhancing its biocompatibility. The present investigation studies the efficiency of plasma polymerization of acrylic acid (AAC) on various gaseous plasma pretreated LDPE films by cold atmospheric pressure plasma, to enhance its cytocompatibility. The change in chemical composition and surface topography of various gaseous plasma pretreated and acrylic deposited LDPE films has been assessed by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The changes in hydrophilic nature of surface modified LDPE films were studied by contact angle (CA) analysis. Cytocompatibility of the AAC/LDPE films was also studied in vitro, using RIN-5F cells. The results acquired by the XPS and AFM analysis clearly proved that cold atmospheric pressure (CAP) plasma assisted polymerization of AAC enhances various surface properties including carboxylic acid functional group density and increased surface roughness on various gaseous plasma treated AAC/LDPE film surfaces. Moreover, contact angle analysis clearly showed that the plasma polymerized samples were hydrophilic in nature. In vitro cytocompatibility analysis undoubtedly validates that the AAC polymerized various plasma pretreated LDPE films surfaces stimulate cell distribution and proliferation compared to pristine LDPE films. Similarly, cytotoxicity analysis indicates that the AAC deposited various gaseous plasma pretreated LDPE film can be considered as non-toxic as well as stimulating cell viability significantly. The cytocompatible properties of AAC polymerized Ar + O2 plasma pretreated LDPE films were found to be more pronounced compared to the other plasma pretreated

Line-Interactive Transformerless Uninterruptible Power Supply (UPS with a Fuel Cell as the Primary Source

Directory of Open Access Journals (Sweden)

Muhammad Iftikhar

2018-03-01

Full Text Available This paper presents line-interactive transformerless Uninterruptible Power Supply (UPS with a fuel cell as the prime energy source. The proposed UPS consists of three major parts (i.e., an output inverter, a unidirectional DC–DC converter, and a battery charger/discharger. Non-isolated topologies of both the unidirectional converter and battery charger/discharger ensure transformerless operation of the UPS system. A new topology of high gain converter is employed for boosting the low voltage of the fuel cell to a higher DC link voltage, with minimum semiconductor count, and high efficiency. A high-gain battery charger/discharger realizes the bidirectional operation between the DC link and the battery bank. Besides, it regulates the DC link voltage during the cold start of fuel cells and keeps the battery bank voltage to only 24 V. A new inverter control scheme is introduced that regulates the output voltage and minimizes the total harmonic distortion for non-linear loading condition. The proposed control scheme integrates proportional-resonant control with slide mode control, which improves the controller’s performance in transient conditions. The proposed UPS system is validated by developing a 1-kVA experimental prototype.

Copper deficiency alters cell bioenergetics and induces mitochondrial fusion through up-regulation of MFN2 and OPA1 in erythropoietic cells

International Nuclear Information System (INIS)

Bustos, Rodrigo I.; Jensen, Erik L.; Ruiz, Lina M.; Rivera, Salvador; Ruiz, Sebastián; Simon, Felipe; Riedel, Claudia; Ferrick, David; Elorza, Alvaro A.

2013-01-01

Highlights: •In copper deficiency, cell proliferation is not affected. In turn, cell differentiation is impaired. •Enlarged mitochondria are due to up-regulation of MNF2 and OPA1. •Mitochondria turn off respiratory chain and ROS production. •Energy metabolism switch from mitochondria to glycolysis. -- Abstract: Copper is essential in cell physiology, participating in numerous enzyme reactions. In mitochondria, copper is a cofactor for respiratory complex IV, the cytochrome c oxidase. Low copper content is associated with anemia and the appearance of enlarged mitochondria in erythropoietic cells. These findings suggest a connection between copper metabolism and bioenergetics, mitochondrial dynamics and erythropoiesis, which has not been explored so far. Here, we describe that bathocuproine disulfonate-induced copper deficiency does not alter erythropoietic cell proliferation nor induce apoptosis. However it does impair erythroid differentiation, which is associated with a metabolic switch between the two main energy-generating pathways. That is, from mitochondrial function to glycolysis. Switching off mitochondria implies a reduction in oxygen consumption and ROS generation along with an increase in mitochondrial membrane potential. Mitochondrial fusion proteins MFN2 and OPA1 were up-regulated along with the ability of mitochondria to fuse. Morphometric analysis of mitochondria did not show changes in total mitochondrial biomass but rather bigger mitochondria because of increased fusion. Similar results were also obtained with human CD34+, which were induced to differentiate into red blood cells. In all, we have shown that adequate copper levels are important for maintaining proper mitochondrial function and for erythroid differentiation where the energy metabolic switch plus the up-regulation of fusion proteins define an adaptive response to copper deprivation to keep cells alive

Copper deficiency alters cell bioenergetics and induces mitochondrial fusion through up-regulation of MFN2 and OPA1 in erythropoietic cells

Energy Technology Data Exchange (ETDEWEB)

Bustos, Rodrigo I.; Jensen, Erik L.; Ruiz, Lina M.; Rivera, Salvador; Ruiz, Sebastián [Center for Biomedical Research, Faculty of Biological Sciences and Faculty of Medicine, Universidad Andres Bello, Santiago (Chile); Simon, Felipe; Riedel, Claudia [Center for Biomedical Research, Faculty of Biological Sciences and Faculty of Medicine, Universidad Andres Bello, Santiago (Chile); Millennium Institute of Immunology and Immunotherapy, Santiago (Chile); Ferrick, David [Seahorse Bioscience, Billerica, MA (United States); Elorza, Alvaro A., E-mail: aelorza@unab.cl [Center for Biomedical Research, Faculty of Biological Sciences and Faculty of Medicine, Universidad Andres Bello, Santiago (Chile); Millennium Institute of Immunology and Immunotherapy, Santiago (Chile)

2013-08-02

Highlights: •In copper deficiency, cell proliferation is not affected. In turn, cell differentiation is impaired. •Enlarged mitochondria are due to up-regulation of MNF2 and OPA1. •Mitochondria turn off respiratory chain and ROS production. •Energy metabolism switch from mitochondria to glycolysis. -- Abstract: Copper is essential in cell physiology, participating in numerous enzyme reactions. In mitochondria, copper is a cofactor for respiratory complex IV, the cytochrome c oxidase. Low copper content is associated with anemia and the appearance of enlarged mitochondria in erythropoietic cells. These findings suggest a connection between copper metabolism and bioenergetics, mitochondrial dynamics and erythropoiesis, which has not been explored so far. Here, we describe that bathocuproine disulfonate-induced copper deficiency does not alter erythropoietic cell proliferation nor induce apoptosis. However it does impair erythroid differentiation, which is associated with a metabolic switch between the two main energy-generating pathways. That is, from mitochondrial function to glycolysis. Switching off mitochondria implies a reduction in oxygen consumption and ROS generation along with an increase in mitochondrial membrane potential. Mitochondrial fusion proteins MFN2 and OPA1 were up-regulated along with the ability of mitochondria to fuse. Morphometric analysis of mitochondria did not show changes in total mitochondrial biomass but rather bigger mitochondria because of increased fusion. Similar results were also obtained with human CD34+, which were induced to differentiate into red blood cells. In all, we have shown that adequate copper levels are important for maintaining proper mitochondrial function and for erythroid differentiation where the energy metabolic switch plus the up-regulation of fusion proteins define an adaptive response to copper deprivation to keep cells alive.

NIR-Emitting Alloyed CdTeSe QDs and Organic Dye Assemblies: A Nontoxic, Stable, and Efficient FRET System

Directory of Open Access Journals (Sweden)

Doris E. Ramírez-Herrera

2018-04-01

Full Text Available In the present work, we synthesize Near Infrared (NIR-emitting alloyed mercaptopropionic acid (MPA-capped CdTeSe quantum dots (QDs in a single-step one-hour process, without the use of an inert atmosphere or any pyrophoric ligands. The quantum dots are water soluble, non-toxic, and highly photostable and have high quantum yields (QYs up to 84%. The alloyed MPA-capped CdTeSe QDs exhibit a red-shifted emission, whose color can be tuned between visible and NIR regions (608–750 nm by controlling the Te:Se molar ratio in the precursor mixtures and/or changing the time reaction. The MPA-capped QDs were characterized by UV-visible absorption spectroscopy, fluorescence spectroscopy, transmission electron microscopy (TEM, energy dispersive X-ray spectroscopy (EDS, and zeta potential measurements. Photostability studies were performed by irradiating the QDs with a high-power xenon lamp. The ternary MPA-CdTeSe QDs showed greater photostability than the corresponding binary MPA-CdTe QDs. We report the Förster resonance energy transfer (FRET from the MPA-capped CdTeSe QDs as energy donors and Cyanine5 NHS-ester (Cy5 dye as an energy acceptor with efficiency (E up to 95%. The distance between the QDs and dye (r, the Förster distance (R0, and the binding constant (K are reported. Additionally, cytocompatibility and cell internalization experiments conducted on human cancer cells (HeLa cells revealed that alloyed MPA-capped CdTeSe QDs are more cytocompatible than MPA-capped CdTe QDs and are capable of ordering homogeneously all over the cytoplasm, which allows their use as potential safe, green donors for biological FRET applications.

Synthesis of manganese oxides and antimony silicates and their applications to take up Thorium-234

International Nuclear Information System (INIS)

Al-Attar, L.; Budeir, Y.

2009-07-01

Birnessite, a layered manganese oxide, antimonysilicate and their corresponding cation-exchange derivatives were tested for their ability to take up thorium using a batch-type method. Sorption experiments were performed in different concentrations of acid, and sodium, potassium and calcium nitrate solutions in order to evaluate the influence of cations likely to be present in waste effluents. The results were expressed in terms of distribution coefficients. Linear regressions of the logarithmic plots enabled the elucidation of exchange mechanisms. Variation in the magnitude and mechanism of thorium sorption on the exchangers was ascribed to structural differences and the exchange properties of the materials, as well as the aqueous chemistry of the actinide element. The work expanded to included investigation of thorium solution' pH in controlling the sorption process. In nitric acid solutions, H-antimonysilicate proved to be the best sorbent. The hydrated layer structure of birnessite allows for facile mobility of the interlayer cations with fast kinetics and little structural rearrangement, making it of great importance for intercalation and ion exchange uses in salt conditions. Potassium had the most, and calcium the least, effect on thorium selectivity by birnessites, when they are present as macro components. Conversely, calcium ions did greatly inhibit the sorption behaviour of the actinide on Ca-doped antimonysilicate. Studying the effect of thorium solution' pH reflected the microcrystal modifications of birnessites occurred during experiments. (authors)

Adhesion, vitality and osteogenic differentiation capacity of adipose derived stem cells seeded on nitinol nanoparticle coatings.

Directory of Open Access Journals (Sweden)

Sarah Strauss

Full Text Available Autologous cells can be used for a bioactivation of osteoimplants to enhance osseointegration. In this regard, adipose derived stem cells (ASCs offer interesting perspectives in implantology because they are fast and easy to isolate. However, not all materials licensed for bone implants are equally suited for cell adhesion. Surface modifications are under investigation to promote cytocompatibility and cell growth. The presented study focused on influences of a Nitinol-nanoparticle coating on ASCs. Possible toxic effects as well as influences on the osteogenic differentiation potential of ASCs were evaluated by viability assays, scanning electron microscopy, immunofluorescence and alizarin red staining. It was previously shown that Nitinol-nanoparticles exert no cell toxic effects to ASCs either in soluble form or as surface coating. Here we could demonstrate that a Nitinol-nanoparticle surface coating enhances cell adherence and growth on Nitinol-surfaces. No negative influence on the osteogenic differentiation was observed. Nitinol-nanoparticle coatings offer new possibilities in implantology research regarding bioactivation by autologous ASCs, respectively enhancement of surface attraction to cells.

Lighting up the brain's reward circuitry.

Science.gov (United States)

Lobo, Mary Kay

2012-07-01

The brain's reward circuit is critical for mediating natural reward behaviors including food, sex, and social interaction. Drugs of abuse take over this circuit and produce persistent molecular and cellular alterations in the brain regions and their neural circuitry that make up the reward pathway. Recent use of optogenetic technologies has provided novel insights into the functional and molecular role of the circuitry and cell subtypes within these circuits that constitute this pathway. This perspective will address the current and future use of light-activated proteins, including those involved in modulating neuronal activity, cellular signaling, and molecular properties in the neural circuitry mediating rewarding stimuli and maladaptive responses to drugs of abuse. © 2012 New York Academy of Sciences.

FDG-PET imaging for the staging and follow-up of small cell lung cancer

International Nuclear Information System (INIS)

Schumacher, T.; Brink, I.; Mix, M.; Reinhardt, M.; Moser, E.; Nitzsche, E.; Herget, G.; Digel, W.; Henke, M.

2001-01-01

The staging procedures for small cell lung cancer do not differ appreciably from those for other forms of lung cancer. For practical purposes, the TNM stages are usually collapsed into a simple binary classification: limited disease and extensive disease. This study was performed to answer the question of whether fluorine-18 labelled 2-deoxy-2-D-glucose positron emission tomography (FDG-PET) imaging permits appropriate work-up (including both primary and follow-up staging) of patients presenting with small cell lung cancer, as compared with currently recommended staging procedures. Thirty-six FDG-PET examinations were performed in 30 patients with histologically proven small cell lung cancer. Twenty-four patients were examined for primary staging while four were imaged for therapy follow-up only. Two patients underwent both primary staging and up to four examinations for therapy follow-up. Static PET imaging was performed according to a standard protocol. Image reconstruction was based on an ordered subset expectation maximization algorithm including post-injection segmented attenuation correction. Results of FDG-PET were compared with those of the sum of other staging procedures. Identical results from FDG-PET and the sum of the other staging procedures were obtained in 23 of 36 examinations (6 x limited disease, 12 x extensive disease, 5 x no evidence of disease). In contrast to the results of conventional staging, FDG-PET indicated extensive disease resulting in an up-staging in seven patients. In one patient in whom there was no evidence for tumour on conventional investigations following treatment, FDG-PET was suggestive of residual viability of the primary tumour. Furthermore, discordant results were observed in five patients with respect to lung, bone, liver and adrenal gland findings, although in these cases the results did not affect staging as limited or extensive disease. Moreover, FDG-PET appeared to be more sensitive for the detection of metastatic

Cell Permeating Nano-Complexes of Amphiphilic Polyelectrolytes Enhance Solubility, Stability, and Anti-Cancer Efficacy of Curcumin.

Science.gov (United States)

Fatima, Munazza T; Chanchal, Abhishek; Yavvari, Prabhu S; Bhagat, Somnath D; Gujrati, Mansi; Mishra, Ram K; Srivastava, Aasheesh

2016-07-11

Many hydrophobic drugs encounter severe bioavailability issues owing to their low aqueous solubility and limited cellular uptake. We have designed a series of amphiphilic polyaspartamide polyelectrolytes (PEs) that solubilize such hydrophobic drugs in aqueous medium and enhance their cellular uptake. These PEs were synthesized through controlled (∼20 mol %) derivatization of polysuccinimide (PSI) precursor polymer with hydrophobic amines (of varying alkyl chain lengths, viz. hexyl, octyl, dodecyl, and oleyl), while the remaining succinimide residues of PSI were opened using a protonable and hydrophilic amine, 2-(2-amino-ethyl amino) ethanol (AE). Curcumin (Cur) was employed as a representative hydrophobic drug to explore the drug-delivery potential of the resulting PEs. Unprecedented enhancement in the aqueous solubility of Cur was achieved by employing these PEs through a rather simple protocol. In the case of PEs containing oleyl/dodecyl residues, up to >65000× increment in the solubility of Cur in aqueous medium could be achieved without requiring any organic solvent at all. The resulting suspensions were physically and chemically stable for at least 2 weeks. Stable nanosized polyelectrolyte complexes (PECs) with average hydrodynamic diameters (DH) of 150-170 nm (without Cur) and 220-270 nm (after Cur loading) were obtained by using submolar sodium polyaspartate (SPA) counter polyelectrolyte. The zeta potential of these PECs ranged from +36 to +43 mV. The PEC-formation significantly improved the cytocompatibility of the PEs while affording reconstitutable nanoformulations having up to 40 wt % drug-loading. The Cur-loaded PECs were readily internalized by mammalian cells (HEK-293T, MDA-MB-231, and U2OS), majorly through clathrin-mediated endocytosis (CME). Cellular uptake of Cur was directly correlated with the length of the alkyl chain present in the PECs. Further, the PECs significantly improved nuclear transport of Cur in cancer cells, resulting in their

Xanthophylls are preferentially taken up compared with beta-carotene by retinal cells via a SRBI-dependent mechanism.

Science.gov (United States)

During, Alexandrine; Doraiswamy, Sundari; Harrison, Earl H

2008-08-01

The purpose of this study was to investigate the mechanisms by which carotenoids [xanthophylls vs. beta-carotene(beta-C)] are taken up by retinal pigment epithelial (RPE) cells. The human RPE cell line, ARPE-19, was used. When ARPE-19 cells were fully differentiated (7-9 weeks), the xanthophylls lutein (LUT) and zeaxanthin (ZEA) were taken up by cells to an extent 2-fold higher than beta-C (P xanthophylls versus the carotene by a process that appears to be entirely SR-BI-dependent for ZEA and partly so for beta-C. This mechanism may explain, in part, the preferential accumulation of xanthophylls in the macula of the retina.

TiO{sub 2}-enriched polymeric powder coatings support human mesenchymal cell spreading and osteogenic differentiation

Energy Technology Data Exchange (ETDEWEB)

Mozumder, Mohammad Sayem; Zhu, Jesse [Department of Chemical and Biochemical Engineering, University of Western Ontario, London, Ontario, N6A 5B9 (Canada); Perinpanayagam, Hiran, E-mail: Hiran.Perinpanayagam@schulich.uwo.ca [Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, N6A 5C1 (Canada)

2011-06-15

Novel polymeric powder coatings (PPC) were prepared by ultrafine powder coating technology and shown to support human mesenchymal cell attachment and growth. PPC surfaces enriched with nano-TiO{sub 2} (nTiO{sub 2}) showed enhanced cellular responses, and were compared to commercially pure titanium (cpTi). After cell attachment and growth, osteogenic differentiation and bone matrix formation ensures osseointegration for implantable biomaterials. Therefore, the objective of this study was to determine if mesenchymal cells grown on PPC could undergo osteogenic differentiation by inducing Runx2 and bone matrix proteins, and then initiate mineralization. Atomic force microscopy revealed intricate three-dimensional micro-topographies, and the measures of nano-roughness and porosity were similar for all PPC surfaces. Scanning electron microscopy showed that the cells attached and spread out over all of the surfaces. After 1 week in osteogenic media, RT-PCR analysis showed the induction of Runx2, the up-regulation of type I collagen, and the initial detection of alkaline phosphatase and bone sialoprotein. After 4 weeks, Alizarin Red staining showed mineral deposition. However, cell spreading and osteogenic differentiation were significantly (P < 0.05) higher on the cpTi controls than on the PPC surfaces. Furthermore, spreading and differentiation were consistently higher on the titanium-enriched PPC-2, -3 and -4 than on the titanium-free PPC-1. Therefore, despite the presence of complex micro-topographies and nano-features, titanium-enrichment enhanced the cellular response, and pure titanium still provided the best substrate. These findings confirm the cytocompatibility of these novel polymeric coatings and suggest that titanium-enrichment and nTiO{sub 2} additives may enhance their performance.

mTOR up-regulation of PFKFB3 is essential for acute myeloid leukemia cell survival

International Nuclear Information System (INIS)

Feng, Yonghuai; Wu, Liusong

2017-01-01

Although mTOR (mammalian target of rapamycin) activation is frequently observed in acute myeloid leukemia (AML) patients, the precise function and the downstream targets of mTOR are poorly understood. Here we revealed that PFKFB3, but not PFKFB1, PFKFB2 nor PFKFB4 was a novel downstream substrate of mTOR signaling pathway as PFKFB3 level was augmented after knocking down TSC2 in THP1 and OCI-AML3 cells. Importantly, PFKFB3 silencing suppressed glycolysis and cell proliferation of TSC2 silencing OCI-AML3 cells and activated apoptosis pathway. These results suggested that mTOR up-regulation of PFKFB3 was essential for AML cells survival. Mechanistically, Rapamycin treatment or Raptor knockdown reduced the expression of PFKFB3 in TSC2 knockdown cells, while Rictor silencing did not have such effect. Furthermore, we also revealed that mTORC1 up-regulated PFKFB3 was dependent on hypoxia-inducible factor 1α (HIF1α), a positive regulator of glycolysis. Moreover, PFKFB3 inhibitor PFK15 and rapamycin synergistically blunted the AML cell proliferation. Taken together, PFKFB3 was a promising drug target in AML patients harboring mTOR hyper-activation.

Taking climate to the market

International Nuclear Information System (INIS)

Boyle, S.

1998-01-01

Since the 1997 Kyoto Protocol set binding targets for greenhouse gas reductions, there has been a rapid increase in interest in emissions trading. This is based on the premise that reduction options may be cheaper in countries such as those of eastern Europe and the developing world, than in others such as the USA and Norway. As long as real emission reductions take place, and given that climate change is a global problem, setting up an emissions trading market should provide a much cheaper option than reductions applied solely at a national level. The real prospects for a viable market, what it will look like, and the deals already taking place are examined. (UK)

Cyclodextrin-Modified Porous Silicon Nanoparticles for Efficient Sustained Drug Delivery and Proliferation Inhibition of Breast Cancer Cells.

Science.gov (United States)

Correia, Alexandra; Shahbazi, Mohammad-Ali; Mäkilä, Ermei; Almeida, Sérgio; Salonen, Jarno; Hirvonen, Jouni; Santos, Hélder A

2015-10-21

Over the past decade, the potential of polymeric structures has been investigated to overcome many limitations related to nanosized drug carriers by modulating their toxicity, cellular interactions, stability, and drug-release kinetics. In this study, we have developed a successful nanocomposite consisting of undecylenic acid modified thermally hydrocarbonized porous silicon nanoparticles (UnTHCPSi NPs) loaded with an anticancer drug, sorafenib, and surface-conjugated with heptakis(6-amino-6-deoxy)-β-cyclodextrin (HABCD) to show the impact of the surface polymeric functionalization on the physical and biological properties of the drug-loaded nanoparticles. Cytocompatibility studies showed that the UnTHCPSi-HABCD NPs were not toxic to breast cancer cells. HABCD also enhanced the suspensibility and both the colloidal and plasma stabilities of the UnTHCPSi NPs. UnTHCPSi-HABCD NPs showed a significantly increased interaction with breast cancer cells compared to bare NPs and also sustained the drug release. Furthermore, the sorafenib-loaded UnTHCPSi-HABCD NPs efficiently inhibited cell proliferation of the breast cancer cells.

Limited energy supply in Müller cells alters glutamate uptake

DEFF Research Database (Denmark)

Toft-Kehler, Anne Katrine; Skytt, Dorte Marie; Poulsen, Kristian Arild

2014-01-01

The viability of retinal ganglion cells (RGC) is essential for the maintenance of visual function. RGC homeostasis is maintained by the surrounding retinal glial cells, the Müller cells, which buffer the extracellular concentration of neurotransmitters and provide the RGCs with energy. This study...... evaluates if glucose-deprivation of Müller cells interferes with their ability to remove glutamate from the extracellular space. The human Müller glial cell line, Moorfields/Institute of Ophthalmology-Müller 1, was used to study changes in glutamate uptake. Excitatory amino acid transporter (EAAT) proteins...... were up-regulated in glucose-deprived Müller cells and glutamate uptake was significantly increased in the absence of glucose. The present findings revealed an up-regulation of EAAT1 and EAAT2 in glucose-deprived Müller cells as well as an increased ability to take up glutamate. Hence, glucose...

Live-cell super-resolution imaging of intrinsically fast moving flagellates

International Nuclear Information System (INIS)

Glogger, M; Subota, I; Spindler, M-C; Engstler, M; Fenz, S F; Stichler, S; Bertlein, S; Teßmar, J; Groll, J

2017-01-01

Recent developments in super-resolution microscopy make it possible to resolve structures in biological cells at a spatial resolution of a few nm and observe dynamical processes with a temporal resolution of ms to μ s. However, the optimal structural resolution requires repeated illumination cycles and is thus limited to chemically fixed cells. For live cell applications substantial improvement over classical Abbe-limited imaging can already be obtained in adherent or slow moving cells. Nonetheless, a large group of cells are fast moving and thus could not yet be addressed with live cell super-resolution microscopy. These include flagellate pathogens like African trypanosomes, the causative agents of sleeping sickness in humans and nagana in livestock. Here, we present an embedding method based on a in situ forming cytocompatible UV-crosslinked hydrogel. The fast cross-linking hydrogel immobilizes trypanosomes efficiently to allow microscopy on the nanoscale. We characterized both the trypanosomes and the hydrogel with respect to their autofluorescence properties and found them suitable for single-molecule fluorescence microscopy (SMFM). As a proof of principle, SMFM was applied to super-resolve a structure inside the living trypanosome. We present an image of a flagellar axoneme component recorded by using the intrinsic blinking behavior of eYFP. (paper)

Pentazocine Protects SN4741 Cells Against MPP+-Induced Cell Damage via Up-Regulation of the Canonical Wnt/β-Catenin Signaling Pathway

Directory of Open Access Journals (Sweden)

Jiancai Wang

2017-06-01

Full Text Available The Wnt/β-catenin signaling pathway has been linked to many neurodegenerative diseases including Parkinson’s disease (PD. A glycoprotein named Dickkopf-1 (Dkk1 can combine with the receptor complex on cell membrane to inhibit Wnt/β-catenin signaling. Opioids, a series of compounds including morphine, fentanyl and pentazocine, have been reported to contribute to the up-regulation of Wnt/β-catenin signaling. Naloxone is an antagonist that has been used as an antidote to opioids through mu-opioid receptor. 1-methyl-4-phenylpyridinium (MPP+, which serves as a selective toxin for dopaminergic neurons, has been used to create experimental models of PD. In our study, we examined the protective effects of pentazocine against MPP+-induced cell death in the nigral dopaminergic cell line, SN4741 and tried to elucidate the molecular mechanisms underlying such protective effects. The data showed that pretreatment with pentazocine significantly rescued the SN4741 cell against MPP+. Moreover, the MPP+-exposed SN4741 cells exhibited a down-regulation of β-catenin, which could be restored by treatment with pentazocine. However, Dkk1 but not naloxonewas associated with the abrogation of protective effect of pentazocine. These results suggest that pentazocine alleviates MPP+-induced SN4741 cells apoptosis via the up-regulation of canonical Wnt/β-catenin signaling.

E2F-1 induces melanoma cell apoptosis via PUMA up-regulation and Bax translocation

International Nuclear Information System (INIS)

Hao, Hongying; Dong, Yanbin; Bowling, Maria T; Gomez-Gutierrez, Jorge G; Zhou, H Sam; McMasters, Kelly M

2007-01-01

PUMA is a pro-apoptotic Bcl-2 family member that has been shown to be involved in apoptosis in many cell types. We sought to ascertain whether induction of PUMA plays a crucial role in E2F-1-induced apoptosis in melanoma cells. PUMA gene and protein expression levels were detected by real-time PCR and Western blot in SK-MEL-2 and HCT116 cell lines after Ad-E2F-1 infection. Activation of the PUMA promoter by E2F-1 overexpression was detected by dual luciferase reporter assay. E2F-1-induced Bax translocation was shown by immunocytochemistry. The induction of caspase-9 activity was measured by caspase-9 colorimetric assay kit. Up-regulation of the PUMA gene and protein by E2F-1 overexpression was detected by real-time PCR and Western blot analysis in the SK-MEL-2 melanoma cell line. In support of this finding, we found six putative E2F-1 binding sites within the PUMA promoter. Subsequent dual luciferase reporter assay showed that E2F-1 expression could increase the PUMA gene promoter activity 9.3 fold in SK-MEL-2 cells. The role of PUMA in E2F-1-induced apoptosis was further investigated in a PUMA knockout cell line. Cell viability assay showed that the HCT116 PUMA-/- cell line was more resistant to Ad-E2F-1-mediated cell death than the HCT116 PUMA+/+ cell line. Moreover, a 2.2-fold induction of the PUMA promoter was also noted in the HCT116 PUMA+/+ colon cancer cell line after Ad-E2F-1 infection. Overexpression of a truncated E2F-1 protein that lacks the transactivation domain failed to up-regulate PUMA promoter, suggesting that PUMA may be a transcriptional target of E2F-1. E2F-1-induced cancer cell apoptosis was accompanied by Bax translocation from the cytosol to mitochondria and the induction of caspase-9 activity, suggesting that E2F-1-induced apoptosis is mediated by PUMA through the cytochrome C/Apaf-1-dependent pathway. Our studies strongly demonstrated that E2F-1 induces melanoma cell apoptosis via PUMA up-regulation and Bax translocation. The signaling

77 FR 61575 - Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to...

Science.gov (United States)

2012-10-10

...: This authorization is effective for a period of 1 year from the date of issuance. ADDRESSES: A copy of... seals (Phoca vitulina), and northern elephant seals (Mirounga angustirostris). The take is expected to... made to each site on SNI up to four times per year in order to complete standardized annual black...

Antitumor effects of a sirtuin inhibitor, tenovin-6, against gastric cancer cells via death receptor 5 up-regulation.

Directory of Open Access Journals (Sweden)

Sachiko Hirai

Full Text Available Up-regulated sirtuin 1 (SIRT1, an NAD+-dependent class III histone deacetylase, deacetylates p53 and inhibits its transcriptional activity, leading to cell survival. SIRT1 overexpression has been reported to predict poor survival in some malignancies, including gastric cancer. However, the antitumor effect of SIRT1 inhibition remains elusive in gastric cancer. Here, we investigated the antitumor mechanisms of a sirtuin inhibitor, tenovin-6, in seven human gastric cancer cell lines (four cell lines with wild-type TP53, two with mutant-type TP53, and one with null TP53. Interestingly, tenovin-6 induced apoptosis in all cell lines, not only those with wild-type TP53, but also mutant-type and null versions, accompanied by up-regulation of death receptor 5 (DR5. In the KatoIII cell line (TP53-null, DR5 silencing markedly attenuated tenovin-6-induced apoptosis, suggesting that the pivotal mechanism behind its antitumor effects is based on activation of the death receptor signal pathway. Although endoplasmic reticulum stress caused by sirtuin inhibitors was reported to induce DR5 up-regulation in other cancer cell lines, we could not find marked activation of its related molecules, such as ATF6, PERK, and CHOP, in gastric cancer cells treated with tenovin-6. Tenovin-6 in combination with docetaxel or SN-38 exerted a slight to moderate synergistic cytotoxicity against gastric cancer cells. In conclusion, tenovin-6 has potent antitumor activity against human gastric cancer cells via DR5 up-regulation. Our results should be helpful for the future clinical development of sirtuin inhibitors.

Cytocompatibility and uptake of halloysite clay nanotubes.

Science.gov (United States)

Vergaro, Viviana; Abdullayev, Elshad; Lvov, Yuri M; Zeitoun, Andre; Cingolani, Roberto; Rinaldi, Ross; Leporatti, Stefano

2010-03-08

Halloysite is aluminosilicate clay with hollow tubular structure of 50 nm external diameter and 15 nm diameter lumen. Halloysite biocompatibility study is important for its potential applications in polymer composites, bone implants, controlled drug delivery, and for protective coating (e.g., anticorrosion or antimolding). Halloysite nanotubes were added to different cell cultures for toxicity tests. Its fluorescence functionalization by aminopropyltriethosilane (APTES) and with fluorescently labeled polyelectrolyte layers allowed following halloysite uptake by the cells with confocal laser scanning microscopy (CLSM). Quantitative Trypan blue and MTT measurements performed with two neoplastic cell lines model systems as a function of the nanotubes concentration and incubation time indicate that halloysite exhibits a high level of biocompatibility and very low cytotoxicity, rendering it a good candidate for household materials and medicine. A combination of transmission electron microscopy (TEM), scanning electron microscopy (SEM), and scanning force microscopy (SFM) imaging techniques have been employed to elucidate the structure of halloysite nanotubes.

Cyanide-induced death of dopaminergic cells is mediated by uncoupling protein-2 up-regulation and reduced Bcl-2 expression

International Nuclear Information System (INIS)

Zhang, X.; Li, L.; Zhang, L.; Borowitz, J.L.; Isom, G.E.

2009-01-01

Cyanide is a potent inhibitor of mitochondrial oxidative metabolism and produces mitochondria-mediated death of dopaminergic neurons and sublethal intoxications that are associated with a Parkinson-like syndrome. Cyanide toxicity is enhanced when mitochondrial uncoupling is stimulated following up-regulation of uncoupling protein-2 (UCP-2). In this study, the role of a pro-survival protein, Bcl-2, in cyanide-mediated cell death was determined in a rat dopaminergic immortalized mesencephalic cell line (N27 cells). Following pharmacological up-regulation of UCP-2 by treatment with Wy14,643, cyanide reduced cellular Bcl-2 expression by increasing proteasomal degradation of the protein. The increased turnover of Bcl-2 was mediated by an increase of oxidative stress following UCP-2 up-regulation. The oxidative stress involved depletion of mitochondrial glutathione (mtGSH) and increased H 2 O 2 generation. Repletion of mtGSH by loading cells with glutathione ethyl ester reduced H 2 O 2 generation and in turn blocked the cyanide-induced decrease of Bcl-2. To determine if UCP-2 mediated the response, RNAi knock down was conducted. The RNAi decreased cyanide-induced depletion of mtGSH, reduced H 2 O 2 accumulation, and inhibited down-regulation of Bcl-2, thus blocking cell death. To confirm the role of Bcl-2 down-regulation in the cell death, it was shown that over-expression of Bcl-2 by cDNA transfection attenuated the enhancement of cyanide toxicity after UCP-2 up-regulation. It was concluded that UCP-2 up-regulation sensitizes cells to cyanide by increasing cellular oxidative stress, leading to an increase of Bcl-2 degradation. Then the reduced Bcl-2 levels sensitize the cells to cyanide-mediated cell death.

Ocular Surface Reconstruction with Cultivated Limbal Epithelial Cells in Limbal Stem Cell Deficiency: One-year Follow-up Results

Directory of Open Access Journals (Sweden)

İsmet Durak

2012-05-01

Full Text Available Pur po se: To evaluate the 1-year follow-up results of cultivated limbal epithelial cell (CLEC transplantation in unilateral limbal stem cell deficiency (LSCD. Ma te ri al and Met hod: One-year follow-up results of five unilateral LSCD patients who had undergone CLEC transplantation were evaluated. Parameters for this evaluation were: fluorescein staining of ocular surface, corneal vascularization and status of epithelium with slit lamp, and visual acuity. 1.5-mm limbal biopsy was performed from the superior limbus of the healthy eyes, broke into two equal pieces, expanded on human amniotic membrane (hAM and inserts for 14 days until getting 20 mm in size. CLECs on hAMs were used directly, and cells on inserts were usedafter detachment procedure. The symblepharon and pannus tissues were removed, superficial keratectomy was performed. CLEC on hAMs were transplanted with the epithelial side up onto the bare corneal stroma, sutured to the conjunctiva with 10-0 nylon sutures. Free CLEC layer from insert was placed on hAM as a second layer, additional hAM was used as a protective layer all over other tissues. Re sults: Median age was 44.4 years (14-71. The etiology was chemical burn in all patients. Median duration of symptoms was 10 years (2-18, median follow-up period was 12.6 (12-12.5 months. Preoperative best corrected visual acuities (BCVA were light perception in three patients, counting fingers at 50 cm in one patient and 3/10 in one patient. Visions were improved in all patients. Postoperative BCVA 12 months after the surgery were between counting fingers at 3 meters to 6/10. There was a temporary hemorrhage between the two layers of hAMs in one patient at the early postoperative period. Peripheral corneal vascularization has occurred in three patients, in patient corneal vascularization has reached to the paracentral area. Dis cus si on: CLEC transplantation is an efficient treatment option for unilateral LSCD in mid-long term. (Turk J

MaxSynBio - Avenues towards creating cells from the bottom up.

Science.gov (United States)

Schwille, Petra; Spatz, Joachim; Landfester, Katharina; Bodenschatz, Eberhard; Herminghaus, Stephan; Sourjik, Victor; Erb, Tobias; Bastiaens, Philippe; Lipowsky, Reinhard; Hyman, Anthony; Dabrock, Peter; Baret, Jean-Christophe; Vidakovic-Koch, Tanja; Bieling, Peter; Dimova, Rumiana; Mutschler, Hannes; Robinson, Tom; Tang, Dora; Wegner, Seraphine; Sundmacher, Kai

2018-05-11

A large Max Planck-based German research consortium ('MaxSynBio') was formed to investigate living systems from a fundamental perspective. The research program of MaxSynBio relies solely on the bottom-up approach to Synthetic Biology. MaxSynBio focuses on the detailed analysis and understanding of essential processes of life, via their modular reconstitution in minimal synthetic systems. The ultimate goal is to construct a basic living unit entirely from non-living components. The fundamental insights gained from the activities in MaxSynBio can eventually be utilized for establishing a new generation of biotechnological processes, which would be based on synthetic cell constructs that replace natural cells currently used in conventional biotechnology. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fuel cells - an option for decentralized power supply?

International Nuclear Information System (INIS)

Ketterer, H.

1995-01-01

Development efforts worldwide are made on industrial-scale power stations with high-temperature fuel cells fuelled with coal gas and with off-gases of up to 1000 C, which will improve the high efficiency of the plant even further. As reported at a conference of the VDI-Gesellschaft Energietechnik, it with still take several decades until these base load power station will be in operation. On the other hand, heating power stations with low-temperature fuel cells in the range up to 200 kW have been tested successfully worldwide. (orig.) [de

PTX3 is up-regulated in epithelial mammary cells during S. aureus intramammary infection in goat

Directory of Open Access Journals (Sweden)

Joel Fernando Soares Filipe

2015-07-01

PTX3 was up-regulated in epithelial mammary cells and in milk cells after S. aureus infection, demonstrating that it represents a first line of immune defense in goat udder. No modulation was observed in macrophages, in the secretum and in the ductal epithelial cells. Further experiments are needed to elucidate the role of PTX3 in the pathogenesis of S. aureus infection.

The juxtamembrane domain in ETV6/FLT3 is critical for PIM-1 up-regulation and cell proliferation

International Nuclear Information System (INIS)

Vu, Hoang Anh; Xinh, Phan Thi; Kano, Yasuhiko; Tokunaga, Katsushi; Sato, Yuko

2009-01-01

We recently reported that the ETV6/FLT3 fusion protein conferred interleukin-3-independent growth on Ba/F3 cells. The present study has been conducted to assess role of the juxtamembrane domain of FLT3 for signal transduction and cell transformation. The wild-type ETV6/FLT3 fusion protein in transfected cells was a constitutively activated tyrosine kinase that led to up-regulation of PIM-1 and activations of STAT5, AKT, and MAPK. Deletion of the juxtamembrane domain abrogated interleukin-3-independent growth of the transfected cells and PIM-1 up-regulation, whereas it retained compatible levels of phosphorylations of STAT5, AKT, and MAPK. Further deletion of N-terminal region of the tyrosine kinase I domain of FLT3 completely abolished these phosphorylations. Our data indicate that the juxtamembrane domain of FLT3 in ETV6/FLT3 fusion protein is critical for cell proliferation and PIM-1 up-regulation that might be independent of a requirement for signaling through STAT5, MAPK, and AKT pathways.

Hooking-Up, Religiosity, and Sexting Among College Students.

Science.gov (United States)

Hall, Michael; Williams, Ronald D; Ford, M Allison; Cromeans, Erin Murphy; Bergman, Randall J

2016-07-28

The purpose of this study was to evaluate the mediation effect of sexting, and taking sexually suggestive photos on religiosity and hooking-up with three separate sexual outcomes. A web-based survey examined the relationship between religiosity and the three hooking-up outcomes among students reporting sexting or taking a sexually suggestive photo in the last 30 days (n = 231). Sexting, as well as taking sexually suggestive photos mediated the relationship between religiosity and hooking-up among females. Sexting may be initiated by females as a way to engage in a nonphysical sexual interaction, which ultimately predisposes them to a physical sexual outcome.

Nutrient acquisition strategies of mammalian cells.

Science.gov (United States)

Palm, Wilhelm; Thompson, Craig B

2017-06-07

Mammalian cells are surrounded by diverse nutrients, such as glucose, amino acids, various macromolecules and micronutrients, which they can import through transmembrane transporters and endolysosomal pathways. By using different nutrient sources, cells gain metabolic flexibility to survive periods of starvation. Quiescent cells take up sufficient nutrients to sustain homeostasis. However, proliferating cells depend on growth-factor-induced increases in nutrient uptake to support biomass formation. Here, we review cellular nutrient acquisition strategies and their regulation by growth factors and cell-intrinsic nutrient sensors. We also discuss how oncogenes and tumour suppressors promote nutrient uptake and thereby support the survival and growth of cancer cells.

Stuck between a ROC and a hard place? Barriers to the take up of green energy in the UK

International Nuclear Information System (INIS)

Diaz-Rainey, Ivan; Ashton, John K.

2008-01-01

This paper examines the UK mechanisms for ensuring future investment in renewable energy through consumer adoption of green energy tariffs and the Renewable Obligation Certificate (ROC) system. Using a national survey and focus groups the stated willingness by UK customers to pay a premium for renewable or green energy and actual take up of such tariffs is assessed. Substantial differences between willingness to pay for and the adoption of green energy tariffs are reported. This disparity is linked to a range of factors including consumer confusion, lack of supply, complexities of constructing 'green source' tariffs under the ROC system and a lack of customer trust. It is concluded that the re-definition of the green energy market in favour of 'green source' tariffs, greater direct compliance with the Renewable Obligation by addressing supply constraints, and efforts in providing clearer information and choices for consumers via a compulsory green energy accreditation scheme are required if willing consumers' are to contribute to investment in renewable energy

Effects of extracellular calcium on calcium transport during hyperthermia of tumor cells.

Science.gov (United States)

Anghileri, L J; Marcha, C; Crone-Escanyé, M C; Robert, J

1985-08-01

The effects of different concentrations of extracellular ion calcium on the transport of calcium by tumor cells have been studied by means of the uptake of radiocalcium. Tumor cells incubated at 45 degrees C take up 4-10 times the amount of radioactivity incorporated by cells incubated at 37 degrees C. The difference is still greater (up to 100 times) for the intracellular incorporation as assessed by elimination of the membrane-bound calcium by EGTA treatment. The possible mechanisms involved in this differential behavior are discussed.

Rho-family GTPase Cdc42 controls migration of Langerhans cells in vivo

DEFF Research Database (Denmark)

Luckashenak, Nancy; Wähe, Anna; Breit, Katharina

2013-01-01

Epidermal Langerhans cells (LCs) of the skin represent the prototype migratory dendritic cell (DC) subtype. In the skin, they take up Ag, migrate to the draining lymph nodes, and contribute to Ag transport and immunity. Different depletion models for LCs have revealed contrasting roles and contri...

Antimicrobial property, cytocompatibility and corrosion resistance of Zn-doped ZrO{sub 2}/TiO{sub 2} coatings on Ti6Al4V implants

Energy Technology Data Exchange (ETDEWEB)

Wang, Ruoyun; He, Xiaojing; Gao, Yuee; Zhang, Xiangyu; Yao, Xiaohong, E-mail: xhyao@tyut.edu.cn; Tang, Bin

2017-06-01

Zn-doped ZrO{sub 2}/TiO{sub 2} porous coatings (Zn-ZrO{sub 2}/TiO{sub 2}) were prepared on the surface of titanium alloy (Ti6Al4V) by a hybrid approach of magnetron sputtering and micro-arc oxidation (MAO). The microstructures, phase constituents and elemental states of the coating were investigated by scanning electron microscope (SEM) equipped with energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The results demonstrate that the Zn-ZrO{sub 2}/TiO{sub 2} coatings are porous and its thickness is approximately 13 μm. The major phases in the oxidation coating are tetragonal ZrO{sub 2} (t-ZrO{sub 2}), cubic ZrO{sub 2} (c-ZrO{sub 2}) and rutile TiO{sub 2}. XPS result reveals that Zn exists as ZnO in the Zn-ZrO{sub 2}/TiO{sub 2} coatings. The biological experiments indicate that Zn-ZrO{sub 2}/TiO{sub 2} coatings exhibit not only excellent antibacterial property against Gram-positive Staphylococcus aureus (S. aureus), but also favorable cytocompatibility. In addition, the corrosion resistance of the coating is also appreciably improved in the simulated body fluids (SBF), which can ensure better biocompatibility in body fluids. - Highlights: • The porous Zn-ZrO{sub 2}/TiO{sub 2} coatings were successfully prepared by a novel duplex-treatment technique. • Zn-ZrO{sub 2}/TiO{sub 2} coatings possess superior corrosion resistance and excellent antibacterial ability against S. aureus. • Zn-ZrO{sub 2}/TiO{sub 2} coatings can enhance in vitro angiogenesis activity of osteoblastic cells.

Xanthophylls are preferentially taken up compared with β-carotene by retinal cells via a SRBI-dependent mechanism*1

Science.gov (United States)

During, Alexandrine; Doraiswamy, Sundari; Harrison, Earl H.

2008-01-01

The purpose of this study was to investigate the mechanisms by which carotenoids [xanthophylls vs. β-carotene(β-C)] are taken up by retinal pigment epithelial (RPE) cells. The human RPE cell line, ARPE-19, was used. When ARPE-19 cells were fully differentiated (7–9 weeks), the xanthophylls lutein (LUT) and zeaxanthin (ZEA) were taken up by cells to an extent 2-fold higher than β-C (P xanthophylls versus the carotene by a process that appears to be entirely SR-BI-dependent for ZEA and partly so for β-C. This mechanism may explain, in part, the preferential accumulation of xanthophylls in the macula of the retina. PMID:18424859

Endothelial Progenitor Cells as Shuttle of Anticancer Agents.

Science.gov (United States)

Laurenzana, Anna; Margheri, Francesca; Chillà, Anastasia; Biagioni, Alessio; Margheri, Giancarlo; Calorini, Lido; Fibbi, Gabriella; Del Rosso, Mario

2016-10-01

Cell therapies are treatments in which stem or progenitor cells are stimulated to differentiate into specialized cells able to home to and repair damaged tissues. After their discovery, endothelial progenitor cells (EPCs) stimulated worldwide interest as possible vehicles to perform autologous cell therapy of tumors. Taking into account the tumor-homing properties of EPCs, two different approaches to control cancer progression have been pursued by combining cell-based therapy with gene therapy or with nanomedicine. The first approach is based on the possibility of engineering EPCs to express different transgenes, and the second is based on the capacity of EPCs to take up nanomaterials. Here we review the most important progress covering the following issues: the characterization of bona fide endothelial progenitor cells, their role in tumor vascularization and metastasis, and preclinical data about their use in cell-based tumor therapy, considering antiangiogenic, suicide, immune-stimulating, and oncolytic virus gene therapy. The mixed approach of EPC cell therapy and nanomedicine is discussed in terms of plasmonic-dependent thermoablation and molecular imaging.

The effect of interferons and viral proteins on antigen-presenting cells in chronic hepatitis B

NARCIS (Netherlands)

A. Boltjes (Arjan)

2014-01-01

markdownabstract__Abstract__ The innate immune system forms the so-called first line of defense against invading pathogens like viruses. Innate immune cells include phagocytes like monocytes, macrophages and dendritic cells (DC). Phagocytes sample their environments, binding and taking up viral

Increasing conversion efficiency of two-step photon up-conversion solar cell with a voltage booster hetero-interface.

Science.gov (United States)

Asahi, Shigeo; Kusaki, Kazuki; Harada, Yukihiro; Kita, Takashi

2018-01-17

Development of high-efficiency solar cells is one of the attractive challenges in renewable energy technologies. Photon up-conversion can reduce the transmission loss and is one of the promising concepts which improve conversion efficiency. Here we present an analysis of the conversion efficiency, which can be increased by up-conversion in a single-junction solar cell with a hetero-interface that boosts the output voltage. We confirm that an increase in the quasi-Fermi gap and substantial photocurrent generation result in a high conversion efficiency.

Scaling-up vaccine production: implementation aspects of a biomass growth observer and controller

OpenAIRE

Soons, Z.I.T.A.; IJssel, van den, J.; Pol, van der, L.A.; Straten, van, G.; Boxtel, van, A.J.B.

2009-01-01

Abstract This study considers two aspects of the implementation of a biomass growth observer and specific growth rate controller in scale-up from small- to pilot-scale bioreactors towards a feasible bulk production process for whole-cell vaccine against whooping cough. The first is the calculation of the oxygen uptake rate, the starting point for online monitoring and control of biomass growth, taking into account the dynamics in the gas-phase. Mixing effects and delays are caused by amongst ...

Bottom-up assembly of salivary gland microtissues for assessing myoepithelial cell function.

Science.gov (United States)

Ozdemir, Tugba; Srinivasan, Padma Pradeepa; Zakheim, Daniel R; Harrington, Daniel A; Witt, Robert L; Farach-Carson, Mary C; Jia, Xinqiao; Pradhan-Bhatt, Swati

2017-10-01

Myoepithelial cells are flat, stellate cells present in exocrine tissues including the salivary glands. While myoepithelial cells have been studied extensively in mammary and lacrimal gland tissues, less is known of the function of myoepithelial cells derived from human salivary glands. Several groups have isolated tumorigenic myoepithelial cells from cancer specimens, however, only one report has demonstrated isolation of normal human salivary myoepithelial cells needed for use in salivary gland tissue engineering applications. Establishing a functional organoid model consisting of myoepithelial and secretory acinar cells is therefore necessary for understanding the coordinated action of these two cell types in unidirectional fluid secretion. Here, we developed a bottom-up approach for generating salivary gland microtissues using primary human salivary myoepithelial cells (hSMECs) and stem/progenitor cells (hS/PCs) isolated from normal salivary gland tissues. Phenotypic characterization of isolated hSMECs confirmed that a myoepithelial cell phenotype consistent with that from other exocrine tissues was maintained over multiple passages of culture. Additionally, hSMECs secreted basement membrane proteins, expressed adrenergic and cholinergic neurotransmitter receptors, and released intracellular calcium [Ca 2+ i ] in response to parasympathetic agonists. In a collagen I contractility assay, activation of contractile machinery was observed in isolated hSMECs treated with parasympathetic agonists. Recombination of hSMECs with assembled hS/PC spheroids in a microwell system was used to create microtissues resembling secretory complexes of the salivary gland. We conclude that the engineered salivary gland microtissue complexes provide a physiologically relevant model for both mechanistic studies and as a building block for the successful engineering of the salivary gland for restoration of salivary function in patients suffering from hyposalivation. Copyright © 2017

Cytocompatibility and Mechanical Properties of Short Phosphate Glass Fibre Reinforced Polylactic Acid (PLA Composites: Effect of Coupling Agent Mediated Interface

Directory of Open Access Journals (Sweden)

Gavin Walker

2012-10-01

Full Text Available In this study three chemical agents Amino-propyl-triethoxy-silane (APS, sorbitol ended PLA oligomer (SPLA and Hexamethylene diisocyanate (HDI were identified to be used as coupling agents to react with the phosphate glass fibre (PGF reinforcement and the polylactic acid (PLA polymer matrix of the composite. Composites were prepared with short chopped strand fibres (l = 20 mm, ϕ = 20 µm in a random arrangement within PLA matrix. Improved, initial composite flexural strength (~20 MPa was observed for APS treated fibres, which was suggested to be due to enhanced bonding between the fibres and polymer matrix. Both APS and HDI treated fibres were suggested to be covalently linked with the PLA matrix. The hydrophobicity induced by these coupling agents (HDI, APS helped to resist hydrolysis of the interface and thus retained their mechanical properties for an extended period of time as compared to non-treated control. Approximately 70% of initial strength and 65% of initial modulus was retained by HDI treated fibre composites in contrast to the control, where only ~50% of strength and modulus was retained after 28 days of immersion in PBS at 37 °C. All coupling agent treated and control composites demonstrated good cytocompatibility which was comparable to the tissue culture polystyrene (TCP control, supporting the use of these materials as coupling agent’s within medical implant devices.

Frédérick Bordry takes up his new position

CERN Multimedia

Antonella Del Rosso & Anaïs Schaeffer

2014-01-01

For Frédérick Bordry, the former head of the Technology (TE) Department, the new year brings a new start as CERN’s Director for Accelerators and Technology. As passionate and enthusiastic as his predecessor Steve Myers, he tells us all about the three key areas of his role.   Frédérick Bordry. Exploitation of the machines “I’m taking on the role of Director for Accelerators and Technology at a crucial time for CERN. This year, we’re going to restart all our non-LHC physics and the LHC injectors, which will allow us to restart the collider at 13 TeV energy next year. LS1 is the priority for 2014. We still have a lot of work to do, but almost all the activities are well within schedule and we are sticking to our philosophy that safety comes first, then quality and finally the schedule. Since the diversity of research is a fundamental aspect of CERN, I would like to highlight that non-LHC physics is also one ...

Analysis of flooding in urban areas, taking into account the residence time of the water on site case of study: Veracruz, México

Directory of Open Access Journals (Sweden)

Faustino De Luna C

2016-01-01

To estimate the damage, shall take into account the hydrodynamic behaviour of the flows. Since houses remain flooded for several days, was the reason to use precipitation level for more than seven days. in the mathematical modelling of flows water with a regular grid made up of cells 10 m by side with the boundary condition downstream, corresponding to the predicted change in the average sea level.

Histones Induce the Procoagulant Phenotype of Endothelial Cells through Tissue Factor Up-Regulation and Thrombomodulin Down-Regulation.

Science.gov (United States)

Kim, Ji Eun; Yoo, Hyun Ju; Gu, Ja Yoon; Kim, Hyun Kyung

2016-01-01

The high circulating levels of histones found in various thrombotic diseases may compromise the anticoagulant barrier of endothelial cells. We determined how histones affect endothelial procoagulant tissue factor (TF) and anticoagulant thrombomodulin (TM). Surface antigens, soluble forms, and mRNA levels of TF and TM were measured by flow cytometry, ELISA, and real-time RT-PCR, respectively. TF and TM activity were measured using procoagulant activity, thrombin generation, or chromogenic assays. Involvement of the toll-like receptor (TLR) was assessed using the neutralizing antibodies. Histones dose-dependently induced surface antigens, activity and mRNA levels of endothelial TF. Histone-treated endothelial cells significantly shortened the lag time and enhanced the endogenous thrombin potential of normal plasma, which was normalized by a TF neutralizing antibody. Histones induced phosphatidylserine and protein-disulfide isomerase expression in endothelial cells. Histones also reduced the surface antigen, activity, and mRNA levels of endothelial TM. Polysialic acid and heparin reversed the histone-induced TF up-regulation and TM down-regulation. Activated protein C did not affect the TF up-regulation, but interrupted TM down-regulation. TLR2, and TLR4 inhibitors partially blocked the TF up-regulation. Histones induced the endothelial procoagulant phenotype through TF up-regulation and TM down-regulation. The effects of histones were partly mediated by TLR2, TLR4. Strategies to inhibit the harmful effects of histones in endothelial cells may be required in order to prevent a thrombotic environment.

Hydro-Quebec International : taking up the challenges of globalization

Energy Technology Data Exchange (ETDEWEB)

Carpentier, J.M.

1997-12-31

With the ever increasing demand for electricity, it is estimated that the world`s electrical generating capacity will grow by about 1,000,000 MW over the next eight years. This represents a 40 per cent increase over today`s capacity. Hydro-Quebec is determined to stake its place in international markets and to maximize the profits from the strong expertise gained during the construction of Quebec`s major electric facilities. The venture into international markets is primarily a commercial strategy. To that effect, Hydro-Quebec plans to invest up to $300 million in international projects around the world so that after five years it can have major interests and assets totaling $12 billion or more. China, North Africa and the Middle East are some of the market that Hydro-Quebec wishes to enter in the years ahead. The Eastern European and Southeast Asian markets are also worthy of interest. It was pointed out that Hydro-Quebec is not the only large electric utility turning to world market to pursue its growth. French, Spanish and American companies are also presently investing billions of dollars in the world market.

Hydro-Quebec International : taking up the challenges of globalization

International Nuclear Information System (INIS)

Carpentier, J.M.

1997-01-01

With the ever increasing demand for electricity, it is estimated that the world''s electrical generating capacity will grow by about 1,000,000 MW over the next eight years. This represents a 40 per cent increase over today''s capacity. Hydro-Quebec is determined to stake its place in international markets and to maximize the profits from the strong expertise gained during the construction of Quebec''s major electric facilities. The venture into international markets is primarily a commercial strategy. To that effect, Hydro-Quebec plans to invest up to $300 million in international projects around the world so that after five years it can have major interests and assets totaling $12 billion or more. China, North Africa and the Middle East are some of the market that Hydro-Quebec wishes to enter in the years ahead. The Eastern European and Southeast Asian markets are also worthy of interest. It was pointed out that Hydro-Quebec is not the only large electric utility turning to world market to pursue its growth. French, Spanish and American companies are also presently investing billions of dollars in the world market

Photoluminescence light-up detection of zinc ion and imaging in living cells based on the aggregation induced emission enhancement of glutathione-capped copper nanoclusters.

Science.gov (United States)

Lin, Liyun; Hu, Yuefang; Zhang, Liangliang; Huang, Yong; Zhao, Shulin

2017-08-15

In this work, we prepared glutathione (GSH)-capped copper nanoclusters (Cu NCs) with red emission by simply adjusting the pH of GSH/Cu 2+ mixture at room temperature. A photoluminescence light-up method for detecting Zn 2+ was then developed based on the aggregation induced emission enhancement of GSH-capped Cu NCs. Zn 2+ could trigger the aggregation of Cu NCs, inducing the enhancement of luminescence and the increase of absolute quantum yield from 1.3% to 6.2%. GSH-capped Cu NCs and the formed aggregates were characterized, and the possible mechanism was also discussed. The prepared GSH-capped Cu NCs exhibited a fast response towards Zn 2+ and a wider detection range from 4.68 to 2240μM. The detection limit (1.17μM) is much lower than that of the World Health Organization permitted in drinking water. Furthermore, taking advantages of the low cytotoxicity, large Stokes shift, red emission and light-up detection mode, we explored the use of the prepared GSH-capped Cu NCs in the imaging of Zn 2+ in living cells. The developed luminescence light-up nanoprobe may hold the potentials for Zn 2+ -related drinking water safety and biological applications. Copyright © 2017 Elsevier B.V. All rights reserved.

Cell internalizable and intracellularly degradable cationic polyurethane micelles as a potential platform for efficient imaging and drug delivery.

Science.gov (United States)

Ding, Mingming; Zeng, Xin; He, Xueling; Li, Jiehua; Tan, Hong; Fu, Qiang

2014-08-11

A cell internalizable and intracellularly degradable micellar system, assembled from multiblock polyurethanes bearing cell-penetrating gemini quaternary ammonium pendent groups in the side chain and redox-responsive disulfide linkages throughout the backbone, was developed for potential magnetic resonance imaging (MRI) and drug delivery. The nanocarrier is featured as a typical "cleavable core-internalizable shell-protective corona" architecture, which exhibits small size, positive surface charge, high loading capacity, and reduction-triggered destabilization. Furthermore, it can rapidly enter tumor cells and release its cargo in response to an intracellular level of glutathione, resulting in enhanced drug efficacy in vitro. The magnetic micelles loaded with superparamagnetic iron oxide (SPIO) nanoparticles demonstrate excellent MRI contrast enhancement, with T2 relaxivity found to be affected by the morphology of SPIO-clustering inside the micelle core. The multifunctional carrier with good cytocompatibility and nontoxic degradation products can serve as a promising theranostic candidate for efficient intracellular delivery of anticancer drugs and real-time monitoring of therapeutic effect.

Direct Light-up of cAMP Derivatives in Living Cells by Click Reactions

Directory of Open Access Journals (Sweden)

Yan Xu

2013-10-01

Full Text Available 8-Azidoadenosine 3′,5′-cyclic monophosphate (8-azido cAMP was directly detected in living cells, by applying Cu-free azide-alkyne cycloaddition to probe cAMP derivatives by fluorescence light-up. Fluorescence emission was generated by two non-fluorescent molecules, 8-azido cAMP as a model target and difluorinated cyclooctyne (DIFO reagent as a probe. The azide-alkyne cycloaddition reaction between 8-azido cAMP and DIFO induces fluorescence in 8-azido cAMP. The fluorescence emission serves as a way to probe 8-azido cAMP in cells.

Cytocompatibility of polyethylene grafted with triethylenetetramine functionalized carbon nanoparticles

Science.gov (United States)

Žáková, Pavlína; Slepičková Kasálková, Nikola; Slepička, Petr; Kolská, Zdeňka; Karpíšková, Jana; Stibor, Ivan; Švorčík, Václav

2017-11-01

Various carbon nanostructures are widely researched as scaffolds for tissue engineering. We evaluated the surface properties and cell-substrate interactions of carbon nanoparticles functionalized with triethylenetetramine (CNPs) grafted polymer film. Two forms of polyethylene (HDPE, LDPE) were treated in an inert argon plasma discharge and, subsequently, grafted with CNPs. The surface properties were studied using multiple methods, including Raman spectroscopy, goniometry, atomic force microscopy, X-ray photoelectron spectroscopy and electrokinetic analysis. Cell-substrate interactions were determined in vitro by studying adhesion, proliferation and viability of vascular smooth muscle cells (VSMCs) from the aorta of a rat. Cell-substrate interactions on pristine and modified substrates were compared to standard tissue culture polystyrene. Our results show that CNPs affect surface morphology and wettability and therefore adhesion, proliferation and viability of cultured muscle cells.

Taking Care of You: Support for Caregivers

Science.gov (United States)

... For Parents / Taking Care of You: Support for Caregivers What's in this article? The Caregiver's Dilemma Tips for Caregivers More Tips Getting Help ... there are moments when the sheer magnitude of what you're up against is so ... not alone. The Caregiver's Dilemma When you're the caregiver of a ...

Foldable and Cytocompatible Sol-gel TiO2 Photonics.

Science.gov (United States)

Li, Lan; Zhang, Ping; Wang, Wei-Ming; Lin, Hongtao; Zerdoum, Aidan B; Geiger, Sarah J; Liu, Yangchen; Xiao, Nicholas; Zou, Yi; Ogbuu, Okechukwu; Du, Qingyang; Jia, Xinqiao; Li, Jingjing; Hu, Juejun

2015-09-07

Integrated photonics provides a miniaturized and potentially implantable platform to manipulate and enhance the interactions between light and biological molecules or tissues in in-vitro and in-vivo settings, and is thus being increasingly adopted in a wide cross-section of biomedical applications ranging from disease diagnosis to optogenetic neuromodulation. However, the mechanical rigidity of substrates traditionally used for photonic integration is fundamentally incompatible with soft biological tissues. Cytotoxicity of materials and chemicals used in photonic device processing imposes another constraint towards these biophotonic applications. Here we present thin film TiO2 as a viable material for biocompatible and flexible integrated photonics. Amorphous TiO2 films were deposited using a low temperature (<250 °C) sol-gel process fully compatible with monolithic integration on plastic substrates. High-index-contrast flexible optical waveguides and resonators were fabricated using the sol-gel TiO2 material, and resonator quality factors up to 20,000 were measured. Following a multi-neutral-axis mechanical design, these devices exhibit remarkable mechanical flexibility, and can sustain repeated folding without compromising their optical performance. Finally, we validated the low cytotoxicity of the sol-gel TiO2 devices through in-vitro cell culture tests. These results demonstrate the potential of sol-gel TiO2 as a promising material platform for novel biophotonic devices.

Remembrance of Dead Cells Past: Discovering That the Extracellular Matrix Is a Cell Survival Factor

OpenAIRE

Schwartz, Martin A.

2010-01-01

In 1992, Jere Meredith and I followed up on a serendipitous observation and showed that matrix deprivation can lead to apoptosis. Our article in Molecular Biology of the Cell, together with work form Steve Frisch's lab, helped establish the paradigm that integrin signals control cell survival in a variety of systems. It has been a pleasure to watch that work take on a life of its own as other investigators have explored its role in processes such as cavitation, regression of the mammary gland...

Short term clinical disease progression in HIV-1 positive patients taking combination antiretroviral therapy : The EuroSIDA risk-score

DEFF Research Database (Denmark)

Mocroft, A; Ledergerber, B; Zilmer, K

2007-01-01

/death in patients taking cART. A score was derived for 4169 patients from EuroSIDA and validated on 5150 patients from the Swiss HIV Cohort Study (SHCS). RESULTS: In EuroSIDA, 658 events occurred during 22 321 person-years of follow-up: an incidence rate of 3.0/100 person-years of follow-up [95% confidence interval...... (CI), 2.7-3.3]. Current levels of viral load, CD4 cell count, CD4 cell slope, anaemia, and body mass index all independently predicted new AIDS/death, as did age, exposure group, a prior AIDS diagnosis, prior antiretroviral treatment and stopping all antiretroviral drugs. The EuroSIDA risk...... in the risk-score was associated with a 2.70 times higher incidence of clinical progression (95% CI, 2.56-2.84) in EuroSIDA and 2.88 (95% CI, 2.75-3.02) in SHCS. CONCLUSIONS: A clinically relevant prognostic score was derived in EuroSIDA and validated within the SHCS, with good agreement. The EuroSIDA risk...

Up-regulation of P-glycoprotein expression by catalase via JNK activation in HepG2 cells.

Science.gov (United States)

Li, Lin; Xu, Jianfeng; Min, Taishan; Huang, Weida

2006-01-01

Overexpression of the MDR1 gene is one of the reasons for multidrug resistance (MDR). Some studies suggested that antioxidants could down-regulate MDR1 expression as a possible cancer treatment. In this report, we try to determine the effects of antioxidants (catalase or N-acetylcysteine [NAC]) on the regulation of intrinsic MDR1 overexpression in HepG2 cells. Adding catalase or N-acetylcysteine to the HepG2 culture led to a significant increase of MDR1 mRNA and P-glycoprotein drug transporter activity. After catalase or NAC treatment, a reduced intracellular reactive oxygen species (ROS) was observed. The JNK inhibitor SP600125 abolished the positive effects of catalase on drug transporter activity in a dose-dependent manner. Furthermore, the up-regulation of P-glycoprotein functions by catalase was only observed in HepG2 cells but not in other cell lines tested (MCF-7, A549, A431). These data suggested that catalase can up-regulate P-glycoprotein expression in HepG2 cells via reducing intracellular ROS, and JNK may mediate this process.

Hairy B-cell lymphoproliferative disorder and its differential diagnosis: a case with long-term follow-up

Directory of Open Access Journals (Sweden)

Kensuke Matsuda

2017-09-01

Full Text Available Hairy B-cell lymphoproliferative disorder (HBLD is one of chronic polyclonal B-cell lymphocytosis. We report a 47-year-old female Japanese patient diagnosed as having HBLD based on lymphocytosis with hairy cell appearance and characteristic phenotypes including CD11c+, and without B-cell monoclonalities. She was a non-smoker, and possessed HLA-DR4. She has been closely followed up without treatment and lymphoma development for over five years. Although this disease is quite rare and has been reported, to our knowledge, in only 13 Japanese cases, an accurate diagnosis, particularly differential diagnosis from persistent polyclonal B-cell lymphocytosis or hairy cell leukemia-Japanese variant is essential for the prevention of unnecessary treatments.

Ectopic pituitary null cell adenoma arising from the infundibulum in the third ventricle: A successful endonasal transsphenoidal resection after long-term follow-up MR imaging – A technical note

Directory of Open Access Journals (Sweden)

Yuichiro Yoneoka, M.D., Ph.D.

2017-12-01

Conclusion: To our best knowledge, this is the first case with long-term preoperative follow-up images, which can bridge the knowledge gap in operations of third ventricle ectPA as following: (1 Truly third ventricle ectPA can exist, (2 the third ventricle ectPA extended into the sella turcica along the pituitary stalk, (3 this ectPA can arise from the suprasellar peri-infundibular ectopic pituitary cells or the pars tuberalis of the adenohypophysis, and therefore adhere to the optic chiasm, (4 thus neurosurgeons should take great care in resection of ectPA arising from the infundibulum, and (5 it can be resected through an endoscopic extended transsphenoidal approach.

Sexuality educators: taking a stand by participating in research

African Journals Online (AJOL)

Sexuality educators: taking a stand by participating in research ... and Sexually Transmitted Infections (STIs) (United Nations Educational, Scientific, .... assimilates new ideas which could assist in keeping up with what learners need from.

Preparing nuclei from cells in monolayer cultures suitable for counting and for following synchronized cells through the cell cycle.

Science.gov (United States)

Butler, W B

1984-08-15

A procedure is described for preparing nuclei from cells in monolayer culture so that they may be counted using an electronic particle counter. It takes only 10 to 15 min, and consists of swelling the cells in hypotonic buffer and then lysing them with the quaternary ammonium salt, ethylhexadecyldimethylammonium bromide. The cells are completely lysed, yielding a suspension of clean single nuclei which is stable, free of debris, and easily counted. The method was developed for a cell line of epithelial origin (MCF-7), which is often difficult to trypsinize to single cells. It works equally well at all cell densities up to and beyond confluence, and has been used with a variety of cells in culture, including 3T3 cells, bovine macrophages, rat mammary epithelial cells, mouse mammary tumor cell lines, and human fibroblasts. The size of the nuclei produced by this procedure is related to their DNA content, and the method is thus suitable for following cultures of synchronized cells through the cell cycle, and for performing differential counts of cells with substantial differences in DNA content.

Follow-up of basal cell carcinomas: an audit of current practice.

Science.gov (United States)

Mc Loone, N M; Tolland, J; Walsh, M; Dolan, O M

2006-07-01

Follow-up of patients after treatment of basal cell carcinoma (BCC) allows for monitoring of recurrence and detection of new tumours, but adds a significant burden to outpatient clinics. At the skin tumour clinic in the dermatology department, the Royal Hospitals, Belfast, all patients are reviewed for 2 years after surgical excision of a low-risk primary BCC. An audit was undertaken to determine the quality of data set recorded relating to prognostic factors for BCCs to determine the rate of recurrence and number of new primary tumours detected and to determine the completeness of follow-up by patients. Patients who had primary BCCs treated by excision were identified from a database held at the clinic. Medical charts were reviewed to determine data recorded about lesions, the number of recurrent BCCs and new tumours detected, and the number of patients completing follow-up. Between January 1999 and December 2000, 114 patients had 121 primary BCCs excised. BCC location and size were recorded in 100% and 35% of cases, respectively. Histological type was stated for morphoeic or multifocal lesions. Two years of follow-up was completed by 53% of patients and 1 year by 78% of patients. The rate of recurrence was low, with 2 BCC recurring within 2 years of excision. The risk of developing a new BCC was 11.6% in the first year and 6.3% in the second year. Follow-up of patients after excision of a low-risk BCC at the clinic has been reduced to 1 year. A proforma has been developed to encourage documentation of prognostic factors.

Immunology: Exhausted T cells perk up

Science.gov (United States)

Williams, Matthew A.; Bevan, Michael J.

2006-02-01

During persistent infections, the immune cells responsible for killing infected cells and maintaining inflammation gradually stop functioning, allowing the pathogen to thrive. But can this process be reversed?

Radiation-induced cell disintegrations in cultured rat hepatoma cells JTC 2

International Nuclear Information System (INIS)

Sakka, Masatoshi

1979-01-01

Disintegration of hepatoma cells of rat were recorded by time lapse cinemicrography for more than 5 days and about 1000 pedigrees were analyzed. Five generations were followed up in control and 2 or 3 generations in irradiated cells. Cells were attached on vessel wall spreading themselves in intermitotic phase while they stood up from the wall in mitotic phase taking a roun form. When a cell disintegrates in interphase the disintegration is called D sub( s) and one in mitotic period D sub( r). The frequency of D sub( s)S' is about 3 times as much as D sub( r)S'. An age of a disintegrated cell in generation 1 and 2 was measured as the previous mitosis was age 0. Generation times of the comparable generations of surviving sister branches of the same pedigrees were used as controls. Most disintegration took place at the same age with surviving sisters indicating a determined, not at random, age of cell death. A cell in an initial state flowed to any one of the following states with or without irradiation; surviving, disintegrated, end cell or escaping out of observation field. A single exposure of 400 to 900 R induced a typical reproductive death but effective extinction of clones was observed only in small pedigrees. Temporary hypothermia and hyperthermia immediately after exposure had no remarkable lethal effects on several early generations. (author)

Nicotine induces cell proliferation in association with cyclin D1 up-regulation and inhibits cell differentiation in association with p53 regulation in a murine pre-osteoblastic cell line

International Nuclear Information System (INIS)

Sato, Tsuyoshi; Abe, Takahiro; Nakamoto, Norimichi; Tomaru, Yasuhisa; Koshikiya, Noboru; Nojima, Junya; Kokabu, Shoichiro; Sakata, Yasuaki; Kobayashi, Akio; Yoda, Tetsuya

2008-01-01

Recent studies have suggested that nicotine critically affects bone metabolism. Many studies have examined the effects of nicotine on proliferation and differentiation, but the underlying molecular mechanisms remain unclear. We examined cell cycle regulators involved in the proliferation and differentiation of MC3T3-E1 cells. Nicotine induced cell proliferation in association with p53 down-regulation and cyclin D1 up-regulation. In differentiated cells, nicotine reduced alkaline phosphatase activity and mineralized nodule formation in dose-dependent manners. Furthermore, p53 expression was sustained in nicotine-treated cells during differentiation. These findings indicate that nicotine promotes the cell cycle and inhibits differentiation in association with p53 regulation in pre-osteoblastic cells

Antimicrobial activity and cytocompatibility of silver nanoparticles coated catheters via a biomimetic surface functionalization strategy

Directory of Open Access Journals (Sweden)

Wu K

2015-12-01

Full Text Available Ke Wu,1 Yun Yang,2,3 Yanmei Zhang,2,3 Jiexi Deng,1 Changjian Lin2,31Department of Cardiology, The Affiliated Dongnan Hospital of Xiamen University, Zhangzhou, 2Department of Medical Materials, Beijing Medical Implant Engineering Research Center, Beijing Naton Technology Group, Beijing, 3State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, People’s Republic of ChinaAbstract: Catheter-related bloodstream infections are a significant problem in the clinic and may result in a serious infection. Here, we developed a facile and green procedure for buildup of silver nanoparticles (AgNPs on the central venous catheters (CVCs surface. Inspired by mussel adhesive proteins, dopamine was used to form a thin polydopamine layer and induce AgNPs formation without additional reductants or stabilizers. The chemical and physicochemical properties of AgNPs coated CVCs were characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, and water contact angle. The Staphylococcus aureus culture experiment was used to study the antibacterial properties. The cytocompatibility was assessed by water soluble tetrazolium salts (WST-1 assay, fluorescence staining, and scanning electron microscopy analysis. The results indicated that the CVCs surface was successfully coated with compact AgNPs. AgNPs were significantly well separated and spherical with a size of 30–50 nm. The density of AgNPs could be modulated by the concentration of silver nitrate solution. The antibacterial activity was dependent on the AgNPs dose. The high dose of AgNPs showed excellent antibacterial activity while associated with increased cytotoxicity. The appropriate density of AgNPs coated CVCs could exhibit improved biocompatibility and maintained evident sterilization effect. It is promising to design mussel-inspired silver releasing CVCs with both

Single-cell axotomy of cultured hippocampal neurons integrated in neuronal circuits.

Science.gov (United States)

Gomis-Rüth, Susana; Stiess, Michael; Wierenga, Corette J; Meyn, Liane; Bradke, Frank

2014-05-01

An understanding of the molecular mechanisms of axon regeneration after injury is key for the development of potential therapies. Single-cell axotomy of dissociated neurons enables the study of the intrinsic regenerative capacities of injured axons. This protocol describes how to perform single-cell axotomy on dissociated hippocampal neurons containing synapses. Furthermore, to axotomize hippocampal neurons integrated in neuronal circuits, we describe how to set up coculture with a few fluorescently labeled neurons. This approach allows axotomy of single cells in a complex neuronal network and the observation of morphological and molecular changes during axon regeneration. Thus, single-cell axotomy of mature neurons is a valuable tool for gaining insights into cell intrinsic axon regeneration and the plasticity of neuronal polarity of mature neurons. Dissociation of the hippocampus and plating of hippocampal neurons takes ∼2 h. Neurons are then left to grow for 2 weeks, during which time they integrate into neuronal circuits. Subsequent axotomy takes 10 min per neuron and further imaging takes 10 min per neuron.

Anticoagulation and endothelial cell behaviors of heparin-loaded graphene oxide coating on titanium surface

Energy Technology Data Exchange (ETDEWEB)

Pan, Chang-Jiang, E-mail: panchangjiang@hyit.edu.cn [Jiangsu Provincial Key Laboratory for Interventional Medical Devices, Huaiyin Institute of Technology, Huai' an 223003 (China); Pang, Li-Qun [Department of General Surgery, Huai' an First People' s Hospital, Nanjing Medical University, Huai' an 223300 (China); Gao, Fei [Zhejiang Zylox Medical Devices Co., Ltd., Hangzhou 310000 (China); Wang, Ya-Nan; Liu, Tao; Ye, Wei; Hou, Yan-Hua [Jiangsu Provincial Key Laboratory for Interventional Medical Devices, Huaiyin Institute of Technology, Huai' an 223003 (China)

2016-06-01

Owing to its unique physical and chemical properties, graphene oxide (GO) has attracted tremendous interest in many fields including biomaterials and biomedicine. The purpose of the present study is to investigate the endothelial cell behaviors and anticoagulation of heparin-loaded GO coating on the titanium surface. To this end, the titanium surface was firstly covered by the polydopamine coating followed by the deposition of the GO coating. Heparin was finally loaded on the GO coating to improve the blood compatibility. The results of attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) indicated that the heparin-loaded GO coating was successfully created on the titanium surface. The scanning electron microscopy (SEM) images indicated that a relative uniform GO coating consisting of multilayer GO sheets was formed on the substrate. The hydrophilicity of the titanium surface was enhanced after the deposition of GO and further improved significantly by the loading heparin. The GO coating can enhance the endothelial cell adhesion and proliferation as compared with polydopamine coating and the blank titanium. Loading heparin on the GO coating can significantly reduce the platelet adhesion and prolong the activated partial thromboplastin time (APTT) while not influence the endothelial cell adhesion and proliferation. Therefore, the heparin-loaded GO coating can simultaneously enhance the cytocompatibility to endothelial cells and blood compatibility of biomaterials. Because the polydopamine coating can be easily prepared on most of biomaterials including polymer, ceramics and metal, thus the approach of the present study may open up a new window of promising an effective and efficient way to promote endothelialization and improve the blood compatibility of blood-contact biomedical devices such as intravascular stents. - Highlights: • Heparin-loaded graphene oxide coating was

HDAC up-regulation in early colon field carcinogenesis is involved in cell tumorigenicity through regulation of chromatin structure.

Directory of Open Access Journals (Sweden)

Yolanda Stypula-Cyrus

Full Text Available Normal cell function is dependent on the proper maintenance of chromatin structure. Regulation of chromatin structure is controlled by histone modifications that directly influence chromatin architecture and genome function. Specifically, the histone deacetylase (HDAC family of proteins modulate chromatin compaction and are commonly dysregulated in many tumors, including colorectal cancer (CRC. However, the role of HDAC proteins in early colorectal carcinogenesis has not been previously reported. We found HDAC1, HDAC2, HDAC3, HDAC5, and HDAC7 all to be up-regulated in the field of human CRC. Furthermore, we observed that HDAC2 up-regulation is one of the earliest events in CRC carcinogenesis and observed this in human field carcinogenesis, the azoxymethane-treated rat model, and in more aggressive colon cancer cell lines. The universality of HDAC2 up-regulation suggests that HDAC2 up-regulation is a novel and important early event in CRC, which may serve as a biomarker. HDAC inhibitors (HDACIs interfere with tumorigenic HDAC activity; however, the precise mechanisms involved in this process remain to be elucidated. We confirmed that HDAC inhibition by valproic acid (VPA targeted the more aggressive cell line. Using nuclease digestion assays and transmission electron microscopy imaging, we observed that VPA treatment induced greater changes in chromatin structure in the more aggressive cell line. Furthermore, we used the novel imaging technique partial wave spectroscopy (PWS to quantify nanoscale alterations in chromatin. We noted that the PWS results are consistent with the biological assays, indicating a greater effect of VPA treatment in the more aggressive cell type. Together, these results demonstrate the importance of HDAC activity in early carcinogenic events and the unique role of higher-order chromatin structure in determining cell tumorigenicity.

A Miniaturized Optical Sensor with Integrated Gas Cell

NARCIS (Netherlands)

Ayerden, N.P.; Ghaderi, M.; De Graaf, G.; Wolffenbuttel, R.F.

2015-01-01

The design, fabrication and characterization of a highly integrated optical gas sensor is presented. The gas cell takes up most of the space in a microspectrometer and is the only component that has so far not been miniaturized. Using the tapered resonator cavity of a linear variable optical filter

Glucose capped silver nanoparticles induce cell cycle arrest in HeLa cells.

Science.gov (United States)

Panzarini, Elisa; Mariano, Stefania; Vergallo, Cristian; Carata, Elisabetta; Fimia, Gian Maria; Mura, Francesco; Rossi, Marco; Vergaro, Viviana; Ciccarella, Giuseppe; Corazzari, Marco; Dini, Luciana

2017-06-01

This study aims to determine the interaction (uptake and biological effects on cell viability and cell cycle progression) of glucose capped silver nanoparticles (AgNPs-G) on human epithelioid cervix carcinoma (HeLa) cells, in relation to amount, 2×10 3 or 2×10 4 NPs/cell, and exposure time, up to 48h. The spherical and well dispersed AgNPs (30±5nm) were obtained by using glucose as reducing agent in a green synthesis method that ensures to stabilize AgNPs avoiding cytotoxic soluble silver ions Ag + release. HeLa cells take up abundantly and rapidly AgNPs-G resulting toxic to cells in amount and incubation time dependent manner. HeLa cells were arrested at S and G2/M phases of the cell cycle and subG1 population increased when incubated with 2×10 4 AgNPs-G/cell. Mitotic index decreased accordingly. The dissolution experiments demonstrated that the observed effects were due only to AgNPs-G since glucose capping prevents Ag + release. The AgNPs-G influence on HeLa cells viability and cell cycle progression suggest that AgNPs-G, alone or in combination with chemotherapeutics, may be exploited for the development of novel antiproliferative treatment in cancer therapy. However, the possible influence of the cell cycle on cellular uptake of AgNPs-G and the mechanism of AgNPs entry in cells need further investigation. Copyright © 2017 Elsevier B.V. All rights reserved.

String theorist takes over as Lucasian Professor

Science.gov (United States)

Banks, Michael

2009-11-01

String theorist Michael Green will be the next Lucasian Professor of Mathematics at Cambridge University. Green, 63, will succeed Stephen Hawking, who held the chair from 1980 before retiring last month at the age of 67 and taking up a distinguished research chair at the Perimeter Institute for Theoretical Physics in Canada (see above).

Radiation up-regulated the expression of VEGF in a canine oral melanoma cell line

International Nuclear Information System (INIS)

Flickinger, I.; Rütgen, B.C.; Gerner, W.; Tichy, A.; Saalmüller, A.; Kleiter, M.; Calice, I.

2013-01-01

To evaluate radiosensitivity and the effects of radiation on the expression of vascular endothelial growth factor (VEGF) and VEGF receptors in the canine oral melanoma cell line, TLM 1, cells were irradiated with doses of 0, 2, 4, 6, 8 and 10 Gray (Gy). Survival rates were then determined by a MTT assay, while vascular endothelial growth factor receptor (VEGFR)-1 and -2 expression was measured by flow cytometry and apoptotic cell death rates were investigated using an Annexin assay. Additionally, a commercially available canine VEGF ELISA kit was used to measure VEGF. Radiosensitivity was detected in TLM 1 cells, and mitotic and apoptotic cell death was found to occur in a radiation dose dependent manner. VEGF was secreted constitutively and significant up-regulation was observed in the 8 and 10 Gy irradiated cells. In addition, a minor portion of TLM 1 cells expressed vascular endothelial growth factor receptor (VEGFR)-1 intracellularly. VEGFR-2 was detected in the cytoplasm and was down-regulated following radiation with increasing dosages. In TLM 1 cells, apoptosis plays an important role in radiation induced cell death. It has also been suggested that the significantly higher VEGF production in the 8 and 10 Gy group could lead to tumour resistance. (author)

Corrosion resistance and biocompatibility of magnesium alloy modified by alkali heating treatment followed by the immobilization of poly (ethylene glycol), fibronectin and heparin

Energy Technology Data Exchange (ETDEWEB)

Pan, Changjiang, E-mail: panchangjiang@hyit.edu.cn [Jiangsu Provincial Key Laboratory for Interventional Medical Devices, Huaiyin Institute of Technology, Huai' an 223003 (China); Hu, Youdong [Department of Geriatrics, The Affiliated Huai' an Hospital of Xuzhou Medical College, Huai' an 223003 (China); Hou, Yu; Liu, Tao; Lin, Yuebin; Ye, Wei; Hou, Yanhua; Gong, Tao [Jiangsu Provincial Key Laboratory for Interventional Medical Devices, Huaiyin Institute of Technology, Huai' an 223003 (China)

2017-01-01

modified by fibronectin or fibronectin/heparin complex can significantly promote endothelial cell adhesion and proliferation. Taking all these results into consideration, the method of the present study can be used for the surface modification of the magnesium alloy to simultaneously impart it better corrosion resistance, favorable blood compatibility and good cytocompatibility to endothelial cells. - Highlights: • The magnesium alloy surface was successfully functionalized with biomolecules. • The resulting modified surface exhibited excellent hydrophilicity and improved anticorrosion. • The hemocompatibility and cytocompatibility of magnesium were enhanced after surface modification. • The method can be used to control the biodegradation behaviors of magnesium alloy and to improve its biocompatibility.

CALCULATION OF OPERATING PARAMETERS OF HIGH-VOLTAGE POWER TAKE-OFF SYSTEM FOR THE PHOTOVOLTAIC FACILITY

Directory of Open Access Journals (Sweden)

R.V. Zaitsev

2016-09-01

Full Text Available Purpose. To ensure maximum production of electric power by photovoltaic vacilities, in addition to using highly efficient photovoltaic modules equipped with solar radiation concentrators must use a highly effective power take-off system. This paper is inscribed to solving the problem of a highly efficient and economic power take-off system development. Methodology. To solving the problem, we implemented three stages. On the first stage examines the dependence of electrical power from the intensity of the incident solar radiation. Based on this, the second stage is calculated the DC-DC converter resonant circuit and its working parameters, and developed circuit diagram of DC-DC converter. On the third stage, we carry out an analysis of power take-off system with step up DC-DC converter working. Results. In this paper, we carry out the analysis of working efficiency for photovoltaic facility power take-off system with step-up boost converter. The result of such analysis show that the efficiency of such system in a wide range of photovoltaic energy module illumination power is at 0.92, whereas the efficiency of classic power take-off systems does not exceed 0.70. Achieved results allow designing a circuit scheme of a controlled bridge resonant step-up converter with digital control. Proposed scheme will ensure reliable operation, fast and accurate location point of maximum power and conversion efficiency up to 0.96. Originality. Novelty of proposed power take-off system solution constitute in implementation of circuit with DC-DC converters, which as it shown by results of carrying out modeling is the most effective. Practical value. Practical implementation of proposed power take-off system design will allow reducing losses in connective wires and increasing the efficiency of such a system up to 92.5% in wide range of photovoltaic energy modules illumination.

[Comparison of fibroblastic cell compatibility of type I collagen-immobilized titanium between electrodeposition and immersion].

Science.gov (United States)

Kyuragi, Takeru

2014-03-01

Titanium is widely used for medical implants. While many techniques for surface modification have been studied for optimizing its biocompatibility with hard tissues, little work has been undertaken to explore ways of maximizing its biocompatibility with soft tissues. We investigated cell attachment to titanium surfaces modified with bovine Type I collagen immobilized by either electrodeposition or a conventional immersion technique. The apparent thickness and durability of the immobilized collagen layer were evaluated prior to incubation of the collagen-immobilized titanium surfaces with NIH/3T3 mouse embryonic fibroblasts. The initial cell attachment and expression of actin and vinculin were evaluated. We determined that the immobilized collagen layer was much thicker and more durable when placed using the electrodeposition technique than the immersion technique. Both protocols produced materials that promoted better cell attachment, growth and structural protein expression than titanium alone. However, electrodeposition was ultimately superior to immersion because it is quicker to perform and produces a more durable collagen coating. We conclude that electrodeposition is an effective technique for immobilizing type I collagen on titanium surfaces, thus improving their cytocompatibility with fibroblasts.

Preparation and characterization of novel antibacterial castor oil-based polyurethane membranes for wound dressing application.

Science.gov (United States)

Yari, Abbas; Yeganeh, Hamid; Bakhshi, Hadi; Gharibi, Reza

2014-01-01

Preparation of novel antibacterial and cytocompatible polyurethane membranes as occlusive dressing, which can provide moist and sterile environment over mild exudative wounds is considered in this work. In this regard, an epoxy-terminated polyurethane (EPU) prepolymer based on castor oil and glycidyltriethylammonium chloride (GTEAC) as a reactive bactericidal agent were synthesized. Polyurethane membranes were prepared through cocuring of EPU and different content of GTEAC with 1,4-butane diamine. The physical and mechanical properties, as well as cytocompatibility and antibacterial performance of prepared membranes were studied. Depending on their chemical formulations, the equilibrium water absorption and water vapor transmission rate values of the membranes were in ranges of 3-85% and 53-154g m(-2) day(-1), respectively. Therefore, these transparent membranes can maintain for a long period the moist environment over the wounds with low exudates. Detailed cytotoxicity analysis of samples against mouse L929 fibroblast and MCA-3D keratinocyte cells showed good level of cytocompatibility of membranes after purification via extraction of residual unreacted GTEAC moieties. The antibacterial activity of the membranes against Escherichia coli and Staphylococcus aureus bacteria was also studied. The membrane containing 50% GTEAC exhibited an effective antibacterial activity, while showed acceptable cytocompatibility and therefore, can be applied as an antibacterial occlusive wound dressing. Copyright © 2013 Wiley Periodicals, Inc., a Wiley Company.

Involvement of up-regulated Necl-5/Tage4/PVR/CD155 in the loss of contact inhibition in transformed NIH3T3 cells

International Nuclear Information System (INIS)

Minami, Yukiko; Ikeda, Wataru; Kajita, Mihoko; Fujito, Tsutomu; Monden, Morito; Takai, Yoshimi

2007-01-01

Normal cells show contact inhibition of cell movement and proliferation, but this is lost following transformation. We found that Necl-5, originally identified as a poliovirus receptor and up-regulated in many cancer cells, enhances growth factor-induced cell movement and proliferation. We showed that when cells contact other cells, Necl-5 interacts in trans with nectin-3 and is removed by endocytosis from the cell surface, resulting in a reduction of cell movement and proliferation. We show here that up-regulation of the gene encoding Necl-5 by the oncogene V12-Ki-Ras causes enhanced cell movement and proliferation. Upon cell-cell contact, de novo synthesis of Necl-5 exceeds the rate of Necl-5 endocytosis, eventually resulting in a net increase in the amount of Necl-5 at the cell surface. In addition, expression of the gene encoding nectin-3 is markedly reduced in transformed cells. Thus, up-regulation of Necl-5 following transformation contributes to the loss of contact inhibition in transformed cells

Model studies on heterogeneous reactions of organic components within aerosols and their influence on the condensation of water: Surface-analytical investigations on the water up-take of fly-ashes before and after exposition to fluoranthene and toluene

International Nuclear Information System (INIS)

Faude, F.; Goschnick, J.

1993-01-01

The condensation of water onto four different fly ashes was investigated without any treatment, after annealing and subsequent to exposure with toluene and fluoranthene. It was intented to reveal the influence of organic aerosol components on atmospheric scavenging from particulate pollutants. Because the interaction with the ambient atmosphere is restricted to a very thin surface layer, surface analysis methods were applied to examine directly the adsorption of water or organic compounds at the surface of the fly ashes. Already some of the fly ashes as received contained organic components, which could be desorbed thermally. After their thermal removal the take-up of water improved considerably. Fluoranthene as well as the far more volatile toluene adsorbed at the particle surfaces and both caused strong impediment of the water take-up of originally hydrophilic fly ashes. The results suggest, that for any type of fly ashes the formation of a hydrophobic organic coating can be expected. This may be a result of organic flue gas components such as fluoranthene which condense downstream onto combustion aerosol particles. Or during transport of fly ash particles through organically polluted areas - e.g. with toluene in the air of busy traffic locations - organic coatings may built up. In all cases the hydrophobic coating interferes with the water take-up resulting at least in a considerable delay of the removal of pollutant particulates from the atmosphere. (orig.) [de

A sub-population of circulating porcine gammadelta T cells can act as professional antigen presenting cells.

Science.gov (United States)

Takamatsu, H-H; Denyer, M S; Wileman, T E

2002-09-10

A sub-population of circulating porcine gammadelta T cells express cell surface antigens associated with antigen presenting cells (APCs), and are able to take up soluble antigen very effectively. Functional antigen presentation by gammadelta T cells to memory helper T cells was studied by inbred pig lymphocytes immunised with ovalbumin (OVA). After removing all conventional APCs from the peripheral blood of immunised pigs, the remaining lymphocytes still proliferated when stimulated with OVA. When gammadelta T cells were further depleted, OVA specific proliferation was abolished, but reconstitution with gammadelta T cells restored proliferation. The proliferation was blocked by monoclonal antibodies (mAb) against MHC class II or CD4, and by pre-treatment of gammadelta T cells with chloroquine. These results indicate that a sub-population of circulating porcine gammadelta T cells act as APCs and present antigen via MHC class II.

Non-take-up of Tax-favored Savings Plans : Are Household Portfolios Optimal?

NARCIS (Netherlands)

Alessie, R.J.M.; Hochgürtel, S.; van Soest, A.H.O.

2001-01-01

Since the early nineties, the Dutch tax system allows for a tax-favored form of risk free savings through employer-sponsored savings plans (ESSPs).Under some conditions and up to a certain amount, the contributions to this plan are tax-deductible, and the returns as well as the withdrawals are

Glucocorticoid up-regulation of high-affinity interleukin 6 receptors on human epithelial cells

International Nuclear Information System (INIS)

Snyers, L.; De Wit, L.; Content, J.

1990-01-01

Interleukin 6 (IL-6) is a potent pleiotropic cytokine, known, among others, to stimulate immunoglobulin production by B cells and to trigger acute-phase protein synthesis by hepatocytes. Similar to IL-1, it is produced by monocytes and macrophages following an inflammatory challenge. Analysis of IL-6 receptor (IL-6R) expression on different human cell lines indicates that dexamethasone could up-regulate the number of IL-6R on one epithelial cell line (UAC) and on two hepatoma cell lines (HepG2 and Hep3B). This effect was confirmed by Scatchard analysis of binding experiments, using [ 35 S]methionine and [ 35 S]cysteine metabolically labeled IL-6. It was confirmed at the level of mRNA expression by Northern blot analysis. These results provide evidence for a link between IL-6 and glucocorticoids. They could represent an example of a system in which one role of glucocorticoids is to define more accurately the target of cytokines, and they could explain, at least partly, the frequently observed synergy between IL-6 and glucocorticoids, notably in the case of hepatocytes

TakeCARE, a Video to Promote Bystander Behavior on College Campuses: Replication and Extension.

Science.gov (United States)

Jouriles, Ernest N; Sargent, Kelli S; Salis, Katie Lee; Caiozzo, Christina; Rosenfield, David; Cascardi, Michele; Grych, John H; O'Leary, K Daniel; McDonald, Renee

2017-08-01

Previous research has demonstrated that college students who view TakeCARE, a video bystander program designed to encourage students to take action to prevent sexual and relationship violence (i.e., bystander behavior), display more bystander behavior relative to students who view a control video. The current study aimed to replicate and extend these findings by testing two different methods of administering TakeCARE and examining moderators of TakeCARE's effects on bystander behavior. Students at four universities ( n = 557) were randomly assigned to one of three conditions: (a) view TakeCARE in a monitored computer lab, (b) view TakeCARE at their own convenience after receiving an email link to the video, or (c) view a video about study skills (control group). Participants completed measures of bystander behavior at baseline and at a 1-month follow-up. Participants in both TakeCARE conditions reported more bystander behavior at follow-up assessments, compared with participants in the control condition. The beneficial effect of TakeCARE did not differ significantly across administration methods. However, the effects of TakeCARE on bystander behavior were moderated by students' perceptions of campus responsiveness to sexual violence, with more potent effects when students perceived their institution as responsive to reports of sexual violence.

Graphene Oxide Hybridized nHAC/PLGA Scaffolds Facilitate the Proliferation of MC3T3-E1 Cells

Science.gov (United States)

Liang, Chunyong; Luo, Yongchao; Yang, Guodong; Xia, Dan; Liu, Lei; Zhang, Xiaomin; Wang, Hongshui

2018-01-01

Biodegradable porous biomaterial scaffolds play a critical role in bone regeneration. In this study, the porous nano-hydroxyapatite/collagen/poly(lactic-co-glycolic acid)/graphene oxide (nHAC/PLGA/GO) composite scaffolds containing different amount of GO were fabricated by freeze-drying method. The results show that the synthesized scaffolds possess a three-dimensional porous structure. GO slightly improves the hydrophilicity of the scaffolds and reinforces their mechanical strength. Young's modulus of the 1.5 wt% GO incorporated scaffold is greatly increased compared to the control sample. The in vitro experiments show that the nHAC/PLGA/GO (1.5 wt%) scaffolds significantly cell adhesion and proliferation of osteoblast cells (MC3T3-E1). This present study indicates that the nHAC/PLGA/GO scaffolds have excellent cytocompatibility and bone regeneration ability, thus it has high potential to be used as scaffolds in the field of bone tissue engineering.

Induction of osteogenic differentiation of adipose derived stem cells by microstructured nitinol actuator-mediated mechanical stress.

Directory of Open Access Journals (Sweden)

Sarah Strauß

Full Text Available The development of large tissue engineered bone remains a challenge in vitro, therefore the use of hybrid-implants might offer a bridge between tissue engineering and dense metal or ceramic implants. Especially the combination of the pseudoelastic implant material Nitinol (NiTi with adipose derived stem cells (ASCs opens new opportunities, as ASCs are able to differentiate osteogenically and therefore enhance osseointegration of implants. Due to limited knowledge about the effects of NiTi-structures manufactured by selective laser melting (SLM on ASCs the study started with an evaluation of cytocompatibility followed by the investigation of the use of SLM-generated 3-dimensional NiTi-structures preseeded with ASCs as osteoimplant model. In this study we could demonstrate for the first time that osteogenic differentiation of ASCs can be induced by implant-mediated mechanical stimulation without support of osteogenic cell culture media. By use of an innovative implant design and synthesis via SLM-technique we achieved high rates of vital cells, proper osteogenic differentiation and mechanically loadable NiTi-scaffolds could be achieved.

Deterministic hydrodynamics: Taking blood apart

Science.gov (United States)

Davis, John A.; Inglis, David W.; Morton, Keith J.; Lawrence, David A.; Huang, Lotien R.; Chou, Stephen Y.; Sturm, James C.; Austin, Robert H.

2006-10-01

We show the fractionation of whole blood components and isolation of blood plasma with no dilution by using a continuous-flow deterministic array that separates blood components by their hydrodynamic size, independent of their mass. We use the technology we developed of deterministic arrays which separate white blood cells, red blood cells, and platelets from blood plasma at flow velocities of 1,000 μm/sec and volume rates up to 1 μl/min. We verified by flow cytometry that an array using focused injection removed 100% of the lymphocytes and monocytes from the main red blood cell and platelet stream. Using a second design, we demonstrated the separation of blood plasma from the blood cells (white, red, and platelets) with virtually no dilution of the plasma and no cellular contamination of the plasma. cells | plasma | separation | microfabrication

Surface microstructure and in vitro analysis of nanostructured akermanite (Ca2MgSi2O7) coating on biodegradable magnesium alloy for biomedical applications.

Science.gov (United States)

Razavi, Mehdi; Fathi, Mohammadhossein; Savabi, Omid; Hashemi Beni, Batoul; Vashaee, Daryoosh; Tayebi, Lobat

2014-05-01

Magnesium (Mg) alloys, owing to their biodegradability and good mechanical properties, have potential applications as biodegradable orthopedic implants. However, several poor properties including low corrosion resistance, mechanical stability and cytocompatibility have prevented their clinical application, as these properties may result in the sudden failure of the implants during the bone healing. In this research, nanostructured akermanite (Ca2MgSi2O7) powder was coated on the AZ91 Mg alloy through electrophoretic deposition (EPD) assisted micro arc oxidation (MAO) method to modify the properties of the alloy. The surface microstructure of coating, corrosion resistance, mechanical stability and cytocompatibility of the samples were characterized with different techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), electrochemical corrosion test, immersion test, compression test and cell culture test. The results showed that the nanostructured akermanite coating can improve the corrosion resistance, mechanical stability and cytocompatibility of the biodegradable Mg alloy making it a promising material to be used as biodegradable bone implants for orthopedic applications. Published by Elsevier B.V.

Street racing video games and risk-taking driving: An Internet survey of automobile enthusiasts.

Science.gov (United States)

Vingilis, Evelyn; Seeley, Jane; Wiesenthal, David L; Wickens, Christine M; Fischer, Peter; Mann, Robert E

2013-01-01

The purpose of this study was to examine the relationships among risky driving attitudes, self-perceptions as a risky driver, playing of "drive'em up" (which rewarded players for frequent traffic and other violations) and "circuit" racing video games as well as self-reported risky driving through a web-based survey of car and racing club members in relation to a socio-cognitive model of the effects of racing video game playing. An Internet questionnaire was developed and included: (1) self-perceptions as a risky driver scales (Driver Thrill Seeking and Competitive Attitude Toward Driving); (2) attitudes regarding street racing; (3) street racing video game playing, and (4) self-reported risky driving (Risk-Taking Driving Scale). A sequential logistic regression was performed entering age and driving exposure as control variables in the first block, self-perceptions as a risky driver in the second block, attitudes in the third block and playing "drive'em up" and "circuit" racing games in the last block to examine their effects on self-reported risk-taking driving. A total of 503 survey respondents were included in the analyses and only 20% reported any risk-taking driving. Higher score on the Competitive Attitude Toward Driving Scale, more positive attitudes toward street racing, and more frequent reported playing of "drive'em up" video games were associated with higher odds on the self-reported Risk-Taking Driving Scale. However, the Driver Thrill Seeking Scale and "circuit" video game playing failed to predict self-reported risk-taking driving. Self-perceptions as a risky driver, positive attitudes toward risky driving and "drive'em up" street-racing games, but not "circuit" racing games, are associated with increased risk-taking driving. These findings are congruent with experimental studies in which games that reward driving violations increased risk taking, suggesting that risk taking may be a function of type of street racing game played by affecting self

Taking up the sustainability challenge

DEFF Research Database (Denmark)

McAloone, Tim C.

2009-01-01

? And how much can we, or should we, design? What is surprising is that around 90% of the waste associated with the average mechanical or mechatronic product has occurred before end-users even get their hands on it. And if the product bears a plug or a battery, it will probably continue to make its most...... optimization for environmental improvement. The tough issue, however, is how to integrate these resources into each and every product development process. The answer, of course, is motivation. What will motivate a company to begin applying environmental improvements into its business practices and, therefore......, also the products? Beyond the altruistic ideals of a few individual employees, motivation can be found in three main sources: regulation (or the threat hereof), market factors, and innovation opportunities. All three of these sources are very relevant for the necessary implementation of ecodesign...

Humankind Takes up Environmental Ethics

Science.gov (United States)

Huiying, Xu

2004-01-01

Environmental ethics examines the relationship between human beings and nature from the moral perspective. It is also a kind of ethics arising from a concern with an earth which is on the verge of losing balance. Environmental ethics originated at the end of the 1940s. Since the 1970s, great progress has been made in environmental ethics. This…

Fluorescent water-Soluble Probes Based on Ammonium Cation Peg Substituted Perylenepisimides: Synthesis, Photophysical Properties, and Live Cell Images

Science.gov (United States)

Yang, Wei; Cai, Jiaxuan; Zhang, Shuchen; Yi, Xuegang; Gao, Baoxiang

2018-01-01

To synthesize perylenbisimides (PBI) fluorescent probes that will improve the water-soluble ability and the cytocompatibility, the synthesis and properties of fluorescent water-soluble probes based on dendritic ammonium cation polyethylene glycol (PEG) substituted perylenebisimides(GPDIs) are presented. As we expected, with increased ammonium cation PEG, the aggregation of the PBI in an aqueous solution is completely suppressed by the hydrophilic ammonium cation PEG groups. And the fluorescence quantum yield increases from 25% for GPDI-1 to 62% for GPDI-2. When incubated with Hela cells for 48 h, the viabilities are 71% (for GPDI-1) and 76% (for GPDI-2). Live cell imaging shows that these probes are efficiently internalized by HeLa cells. The study of the photophysical properties indicated increasing the ammonium cation PEG generation can increase the fluorescence quantum yield. Live cell imaging shows that with the ammonium cation PEG chains of perylenebisimides has high biocompatibility. The exceptionally low cytotoxicity is ascribed to the ammonium cation PEG chains, which protect the dyes from nonspecifically interacting with the extracellular proteins. Live cell imaging shows that ammonium cations PEG chains can promote the internalization of these probes.

Pharmacoeconomic impact of up-front use of plerixafor for autologous stem cell mobilization in patients with multiple myeloma.

Science.gov (United States)

Kim, Sara S; Renteria, Anne S; Steinberg, Amir; Banoff, Karen; Isola, Luis

2014-11-01

Stem cell collection can be a major component of overall cost of autologous stem cell transplantation (ASCT). Plerixafor is an effective agent for mobilization; however, it is often reserved for salvage therapy because of its high cost. We present data on the pharmacoeconomic impact of the use of plerixafor as an up-front mobilization in patients with multiple myeloma (MM). Patients with MM who underwent ASCT between January 2008 and April 2011 at the Mount Sinai Medical Center were reviewed retrospectively. In April 2010, practice changes were instituted for patients with MM to delay initiation of granulocyte-colony-stimulating factor (G-CSF) support from day 0 to day +5 and to add plerixafor to G-CSF as an up-front autologous mobilization. Targets of collection were 5-10 × 10(6) CD34(+) cells/kg. Of 50 adults with MM who underwent ASCT, 25 received plerixafor/filgrastim and 25 received G-CSF alone as an up-front mobilization. Compared with the control, plerixafor mobilization yielded higher CD34(+) cell content (16.1 versus 8.4 × 10(6) CD34(+) cells/kg; P = 0.0007) and required fewer sessions of apheresis (1.9 versus 3.1; P = 0.0001). In the plerixafor group, the mean number of plerixafor doses required per patient was 1.8. Although the overall cost of medications was higher in the plerixafor group, the cost for blood products and overall cost of hospitalization were similar between the two groups. Up-front use of plerixafor is an effective mobilization strategy in patients with MM and does not have a substantial pharmacoeconomic impact in overall cost of hospitalization combined with the apheresis procedure. Copyright © 2014 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

Microfluidic assisted one-step fabrication of porous silicon@acetalated dextran nanocomposites for precisely controlled combination chemotherapy.

Science.gov (United States)

Liu, Dongfei; Zhang, Hongbo; Mäkilä, Ermei; Fan, Jin; Herranz-Blanco, Bárbara; Wang, Chang-Fang; Rosa, Ricardo; Ribeiro, António J; Salonen, Jarno; Hirvonen, Jouni; Santos, Hélder A

2015-01-01

An advanced nanocomposite consisting of an encapsulated porous silicon (PSi) nanoparticle and an acid-degradable acetalated dextran (AcDX) matrix (nano-in-nano), was efficiently fabricated by a one-step microfluidic self-assembly approach. The obtained nano-in-nano PSi@AcDX composites showed improved surface smoothness, homogeneous size distribution, and considerably enhanced cytocompatibility. Furthermore, multiple drugs with different physicochemical properties have been simultaneously loaded into the nanocomposites with a ratiometric control. The release kinetics of all the payloads was predominantly controlled by the decomposition rate of the outer AcDX matrix. To facilitate the intracellular drug delivery, a nona-arginine cell-penetrating peptide (CPP) was chemically conjugated onto the surface of the nanocomposites by oxime click chemistry. Taking advantage of the significantly improved cell uptake, the proliferation of two breast cancer cell lines was markedly inhibited by the CPP-functionalized multidrug-loaded nanocomposites. Overall, this nano-in-nano PSi@polymer composite prepared by the microfluidic self-assembly approach is a universal platform for nanoparticles encapsulation and precisely controlled combination chemotherapy. Copyright © 2014 Elsevier Ltd. All rights reserved.

Isoreserpine promotes {beta}-catenin degradation via Siah-1 up-regulation in HCT116 colon cancer cells

Energy Technology Data Exchange (ETDEWEB)

Gwak, Jungsug; Song, Taeyun [PharmacoGenomics Research Center, Inje University, Busan 614-735 (Korea, Republic of); Song, Jie-Young; Yun, Yeon-Sook [Laboratory of Radiation Cancer Science, Korea Institute of Radiological and Medical Sciences, Seoul 139-706 (Korea, Republic of); Choi, Il-Whan [Department of Microbiology, Center for Viral Disease Research, Inje University College of Medicine, Busan 614-735 (Korea, Republic of); Jeong, Yongsu [Department of Genetic Engineering, and Graduate School of Biotechnology, Kyung Hee University, Yongin 446-701 (Korea, Republic of); Shin, Jae-Gook [PharmacoGenomics Research Center, Inje University, Busan 614-735 (Korea, Republic of); Department of Clinical Pharmacology, Inje University Busan Paik Hospital, Busan 614-735 (Korea, Republic of); Oh, Sangtaek, E-mail: ohsa@inje.ac.kr [PharmacoGenomics Research Center, Inje University, Busan 614-735 (Korea, Republic of)

2009-09-25

Aberrant accumulation of intracellular {beta}-catenin in intestinal epithelial cells is a frequent early event during the development of colon cancer. To identify small molecules that decrease the level of intracellular {beta}-catenin, we performed cell-based chemical screening using genetically engineered HEK293 reporter cells to detect compounds that inhibit TOPFlash reporter activity, which was stimulated by Wnt3a-conditioned medium. We found that isoreserpine promoted the degradation of intracellular {beta}-catenin by up-regulation of Siah-1 in HEK293 and HCT116 colon cancer cells. Moreover, isoreserpine repressed the expression of {beta}-catenin/T-cell factor (TCF)-dependent genes, such as cyclin D1 and c-myc, resulting in the suppression of HCT116 cell proliferation. Our findings suggest that isoreserpine can potentially be used as a chemotherapeutic agent against colon cancer.

Take Charge. Take the Test. PSA (:30)

Centers for Disease Control (CDC) Podcasts

As part of the Take Charge. Take the Test. campaign, this 30 second PSA encourages African American women to get tested for HIV. Locations for a free HIV test can be found by visiting hivtest.org/takecharge or calling 1-800-CDC-INFO (1-800-232-4636).

γ-irradiated ribosomes from Micrococcus radiodurans in a cell-free protein synthesizing system

International Nuclear Information System (INIS)

Suessmuth, R.; Widmann, A.

1979-01-01

γ-irradiation inactivation of isolated ribosomes of Micrococcus radiodurans was studied by examining poly U directed synthesis of polyphenylalanine. Ribosomes of M. radiodurans did not show significant γ-radiation sensitivity up to a dose of approx. 11.6 k Gy. Cells of M. radiodurans take up more magnesium than E. coli cells under the same conditions. The magnesium content of ribosomes of M. radiodurans was 18% higher than that of E.coli ribosomes. A possible relation between Mg 2+ -content and γ-resistance is discussed. (orig.) [de

Mechanism of sphingosine 1-phosphate- and lysophosphatidic Acid-induced up-regulation of adhesion molecules and eosinophil chemoattractant in nerve cells.

LENUS (Irish Health Repository)

Costello, Richard W

2012-02-01

The lysophospholipids sphingosine 1-phosphate (S1P) and lysophosphatidic acid (LPA) act via G-protein coupled receptors S1P(1-5) and LPA(1-3) respectively, and are implicated in allergy. Eosinophils accumulate at innervating cholinergic nerves in asthma and adhere to nerve cells via intercellular adhesion molecule-1 (ICAM-1). IMR-32 neuroblastoma cells were used as an in vitro cholinergic nerve cell model. The G(i) coupled receptors S1P(1), S1P(3), LPA(1), LPA(2) and LPA(3) were expressed on IMR-32 cells. Both S1P and LPA induced ERK phosphorylation and ERK- and G(i)-dependent up-regulation of ICAM-1 expression, with differing time courses. LPA also induced ERK- and G(i)-dependent up-regulation of the eosinophil chemoattractant, CCL-26. The eosinophil granule protein eosinophil peroxidase (EPO) induced ERK-dependent up-regulation of transcription of S1P(1), LPA(1), LPA(2) and LPA(3), providing the situation whereby eosinophil granule proteins may enhance S1P- and\\/or LPA- induced eosinophil accumulation at nerve cells in allergic conditions.

Mechanism of sphingosine 1-phosphate- and lysophosphatidic Acid-induced up-regulation of adhesion molecules and eosinophil chemoattractant in nerve cells.

LENUS (Irish Health Repository)

Costello, Richard W

2011-05-01

The lysophospholipids sphingosine 1-phosphate (S1P) and lysophosphatidic acid (LPA) act via G-protein coupled receptors S1P(1-5) and LPA(1-3) respectively, and are implicated in allergy. Eosinophils accumulate at innervating cholinergic nerves in asthma and adhere to nerve cells via intercellular adhesion molecule-1 (ICAM-1). IMR-32 neuroblastoma cells were used as an in vitro cholinergic nerve cell model. The G(i) coupled receptors S1P(1), S1P(3), LPA(1), LPA(2) and LPA(3) were expressed on IMR-32 cells. Both S1P and LPA induced ERK phosphorylation and ERK- and G(i)-dependent up-regulation of ICAM-1 expression, with differing time courses. LPA also induced ERK- and G(i)-dependent up-regulation of the eosinophil chemoattractant, CCL-26. The eosinophil granule protein eosinophil peroxidase (EPO) induced ERK-dependent up-regulation of transcription of S1P(1), LPA(1), LPA(2) and LPA(3), providing the situation whereby eosinophil granule proteins may enhance S1P- and\\/or LPA- induced eosinophil accumulation at nerve cells in allergic conditions.

Ionizing radiation and nitric oxide donor sensitize Fas-induced apoptosis via up-regulation of Fas in human cervical cancer cells

International Nuclear Information System (INIS)

Park, In Chul; Woo, Sang Hyeok; Park, Myung Jin; Lee, Hyung Chahn; Lee Su Jae; Hong, Young Joon; Lee, Seung Hoon; Hong, Seok II; Rhee, Chang Hun

2004-01-01

Fas/CD95/Apo1 is a transmembrane receptor known to trigger apoptotic cell death in several cell types. In the present study, we showed that ionizing radiation (IR) and NO donor, S-nitroso-N-acetyl-penicillamine (SNAP), sensitized Fas-induced apoptotic cell death of HeLa human cervical cancers. Suboptimal dose of IR and SNAP up-regulated cell-surface Fas antigen, detected by FACScan using FITC-anti-Fas antibody. When combined with IR or SNAP, agonistic anti-Fas antibody CH-11 resulted in marked enhancement of apoptosis. This sensitization was completely abrogated by anti-Fas neutralizing antibody ZB4. During the IR and SNAP sensitized Fas-induced apoptosis, mitochondria permeabilization, cytochrome c release, and DNA fragmentation were detected. Furthermore, combined treatment of IR and SNAP additively up-regulated the surface Fas protein expression and sensitized Fas-induced apoptosis. Our finding demonstrate that sensitization of HeLa cervical cells to Fas-mediated apoptosis by IR and NO donor is most likely due to the up-regulation of Fas expression and also provides a means with which to sensitize tumors to the killing effects of cancer therapy via the Fas receptor

Development of high pressure rinsing set up for 650 MHz, 5- cell superconducting RF cavity cleaning

International Nuclear Information System (INIS)

Suhane, S.K.; Chauhan, S.K.; Bose, A.; Kokil, S.V.; Rajput, D.S.; Oraon, B.; Md Hussain; Sahu, A.; Raghavendra, S.; Joshi, S.C.

2015-01-01

High pressure rinsing (HPR) is an ultra-cleanliness process for the surface preparation of high field superconducting RF cavities. Any dust particle or chemical residue on the interior of cavity causes field emission. Jets of high pressure (80-100 bar) ultra pure water dislodge surface contaminants that normally resist removal with conventional rinsing procedures, leading to substantial reduction in field emission and better cavity performance. For cleaning of 650 MHz, 5-cell SRF cavities, a high pressure rinsing set up has been developed at RRCAT. The HPR tool has a rotating wand coaxial with the vertically mounted SRF cavity that is moving up and down. Fan style spray nozzles are attached to the end of the rotating wand and the water jets emerging from spray nozzles scan the entire internal surface of the cavity. The set-up was installed in a specially built clean area meeting cleanliness class 100 standards. The ultrapure water with resistivity 2 ≥ 18 MΩ-cm required for rinsing is obtained from a dedicated water purification system installed for this purpose. The paper describes the salient design and constructional details of the high pressure rinsing set up. Characterization of water jet parameters based on the momentum transfer between the water jet and a load cell is also presented. (author)

Direct intramyocardial mesenchymal stromal cell injections in patients with severe refractory angina - one year follow-up

DEFF Research Database (Denmark)

Haack-Sørensen, Mandana; Friis, Tina; Mathiasen, Anders B

2013-01-01

Aims: In patients with stable coronary artery disease (CAD) and refractory angina we performed direct intra-myocardial injections of autologous mesenchymal stromal cells (MSCs) and followed the safety and efficacy of the treatment for 12 months. Methods and Results: A total of 31 patients...... with stable CAD, moderate to severe angina, normal left ventricular ejection fraction and no further revascularization options, were included. Bone marrow MSCs were isolated and culture expanded for 6 - 8 weeks and then stimulated with vascular endothelial growth factor (VEGF) for one week.The 12 months...... follow-up demonstrated, that it was safe to culture expand MSCs and use the cells for clinical treatment. The patients maximal metabolic equivalent (MET) during exercise increased from 4.23 MET at baseline to 4.72 MET at 12 months follow-up (p...

Homeobox A7 stimulates breast cancer cell proliferation by up-regulating estrogen receptor-alpha

International Nuclear Information System (INIS)

Zhang, Yu; Cheng, Jung-Chien; Huang, He-Feng; Leung, Peter C.K.

2013-01-01

Highlights: •HOXA7 regulates MCF7 cell proliferation. •HOXA7 up-regulates ERα expression. •HOXA7 mediates estrogen-induced MCF7 cell proliferation. -- Abstract: Breast cancer is the most common hormone-dependent malignancy in women. Homeobox (HOX) transcription factors regulate many cellular functions, including cell migration, proliferation and differentiation. The aberrant expression of HOX genes has been reported to be associated with human reproductive cancers. Estradiol (E2) and its nuclear receptors, estrogen receptor (ER)-alpha and ER-beta, are known to play critical roles in the regulation of breast cancer cell growth. However, an understanding of the potential relationship between HOXA7 and ER in breast cancer cells is limited. In this study, our results demonstrate that knockdown of HOXA7 in MCF7 cells significantly decreased cell proliferation and ERα expression. In addition, HOXA7 knockdown attenuated E2-induced cell proliferation as well as progesterone receptor (PR) expression. The stimulatory effects of E2 on cell proliferation and PR expression were abolished by co-treatment with ICI 182780, a selective ERα antagonist. In contrast, overexpression of HOXA7 significantly stimulated cell proliferation and ERα expression. Moreover, E2-induced cell proliferation, as well as PR expression, was enhanced by the overexpression of HOXA7. Neither knockdown nor overexpression of HOXA7 affected the ER-beta levels. Our results demonstrate a novel mechanistic role for HOXA7 in modulating breast cancer cell proliferation via regulation of ERα expression. This finding contributes to our understanding of the role HOXA7 plays in regulating the proliferation of ER-positive cancer cells

Homeobox A7 stimulates breast cancer cell proliferation by up-regulating estrogen receptor-alpha

Energy Technology Data Exchange (ETDEWEB)

Zhang, Yu [Department of Reproductive Endocrinology, Women’s Hospital, School of Medicine, Zhejiang University, Hangzhou 310006 (China); Department of Obstetrics and Gynaecology, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia V5Z 4H4 (Canada); Cheng, Jung-Chien [Department of Obstetrics and Gynaecology, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia V5Z 4H4 (Canada); Huang, He-Feng, E-mail: huanghefg@hotmail.com [Department of Reproductive Endocrinology, Women’s Hospital, School of Medicine, Zhejiang University, Hangzhou 310006 (China); Leung, Peter C.K., E-mail: peter.leung@ubc.ca [Department of Reproductive Endocrinology, Women’s Hospital, School of Medicine, Zhejiang University, Hangzhou 310006 (China); Department of Obstetrics and Gynaecology, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia V5Z 4H4 (Canada)

2013-11-01

Highlights: •HOXA7 regulates MCF7 cell proliferation. •HOXA7 up-regulates ERα expression. •HOXA7 mediates estrogen-induced MCF7 cell proliferation. -- Abstract: Breast cancer is the most common hormone-dependent malignancy in women. Homeobox (HOX) transcription factors regulate many cellular functions, including cell migration, proliferation and differentiation. The aberrant expression of HOX genes has been reported to be associated with human reproductive cancers. Estradiol (E2) and its nuclear receptors, estrogen receptor (ER)-alpha and ER-beta, are known to play critical roles in the regulation of breast cancer cell growth. However, an understanding of the potential relationship between HOXA7 and ER in breast cancer cells is limited. In this study, our results demonstrate that knockdown of HOXA7 in MCF7 cells significantly decreased cell proliferation and ERα expression. In addition, HOXA7 knockdown attenuated E2-induced cell proliferation as well as progesterone receptor (PR) expression. The stimulatory effects of E2 on cell proliferation and PR expression were abolished by co-treatment with ICI 182780, a selective ERα antagonist. In contrast, overexpression of HOXA7 significantly stimulated cell proliferation and ERα expression. Moreover, E2-induced cell proliferation, as well as PR expression, was enhanced by the overexpression of HOXA7. Neither knockdown nor overexpression of HOXA7 affected the ER-beta levels. Our results demonstrate a novel mechanistic role for HOXA7 in modulating breast cancer cell proliferation via regulation of ERα expression. This finding contributes to our understanding of the role HOXA7 plays in regulating the proliferation of ER-positive cancer cells.

Transcriptional up-regulation of restin by all-trans retinoic acid through STAT1 in cancer cell differentiation process

International Nuclear Information System (INIS)

Fu Haiyan; Yang Guodong; Lu Fan; Wang Ruihua; Yao Libo; Lu Zifan

2006-01-01

RESTIN, a member of the melanoma-associated antigen superfamily, is a nuclear protein induced by atRA (all-trans retinoic acid) in HL60 cells. HeLa cells stably transfected with restin results in G1 cell cycle arrest. How this gene is regulated by atRA in the cell differentiation process is still unclear. In this study, we observed that up-regulation of restin was present during the atRA-induced HL60 cell differentiation process, suggesting the functional relevance between RESTIN and atRA-induced cellular effects. In order to further define the transcriptional regulation of restin by atRA, we analyzed the promoter region of restin. About 2.1 kb 5' flanking sequence of this gene was cloned into vector pGL3 and its core promoter region was identified through systemic deletions. Interestingly, restin promoter containing several potential consensus-binding sites of STAT-1α was activated by atRA in ER + MCF-7 cells but not in ER - MDA-MB-231 cells, over-expression of STAT-1α in latter rescued the activation effect of restin promoter in response to atRA and IFNγ. Our evidence supported that STAT-1α plays an important role in the atRA-induced transcriptional up-regulation of restin, which was associated with the atRA-induced HL60 cell differentiation and potentially mediated the downstream effects of atRA signal pathway via STAT-1α in some cancer cells

Biodegradable electrospun nanofibers coated with platelet-rich plasma for cell adhesion and proliferation

International Nuclear Information System (INIS)

Diaz-Gomez, Luis; Alvarez-Lorenzo, Carmen; Concheiro, Angel; Silva, Maite; Dominguez, Fernando; Sheikh, Faheem A.; Cantu, Travis; Desai, Raj; Garcia, Vanessa L.; Macossay, Javier

2014-01-01

Biodegradable electrospun poly(ε-caprolactone) (PCL) scaffolds were coated with platelet-rich plasma (PRP) to improve cell adhesion and proliferation. PRP was obtained from human buffy coat, and tested on human adipose-derived mesenchymal stem cells (MSCs) to confirm cell proliferation and cytocompatibility. Then, PRP was adsorbed on the PCL scaffolds via lyophilization, which resulted in a uniform sponge-like coating of 2.85 (S.D. 0.14) mg/mg. The scaffolds were evaluated regarding mechanical properties (Young's modulus, tensile stress and tensile strain), sustained release of total protein and growth factors (PDGF-BB, TGF-β1 and VEGF), and hemocompatibility. MSC seeded on the PRP–PCL nanofibers showed an increased adhesion and proliferation compared to pristine PCL fibers. Moreover, the adsorbed PRP enabled angiogenesis features observed as neovascularization in a chicken chorioallantoic membrane (CAM) model. Overall, these results suggest that PRP–PCL scaffolds hold promise for tissue regeneration applications. - Highlights: • Platelet-rich plasma (PRP) can be adsorbed on electrospun fibers via lyophilization. • PRP coating enhanced mesenchymal stem cell adhesion and proliferation on scaffolds. • PRP-coated scaffolds showed sustained release of growth factors. • Adsorbed PRP provided angiogenic features. • PRP-poly(ε-caprolactone) scaffolds hold promise for tissue regeneration applications

Biodegradable electrospun nanofibers coated with platelet-rich plasma for cell adhesion and proliferation

Energy Technology Data Exchange (ETDEWEB)

Diaz-Gomez, Luis [Departamento de Farmacia y Tecnología Farmacéutica, Facultad de Farmacia, Universidad de Santiago de Compostela, 15872 Santiago de Compostela (Spain); Instituto de Ortopedia y Banco de Tejidos Musculoesqueléticos, Universidad de Santiago de Compostela, 15872 Santiago de Compostela (Spain); Alvarez-Lorenzo, Carmen, E-mail: carmen.alvarez.lorenzo@usc.es [Departamento de Farmacia y Tecnología Farmacéutica, Facultad de Farmacia, Universidad de Santiago de Compostela, 15872 Santiago de Compostela (Spain); Concheiro, Angel [Departamento de Farmacia y Tecnología Farmacéutica, Facultad de Farmacia, Universidad de Santiago de Compostela, 15872 Santiago de Compostela (Spain); Silva, Maite [Instituto de Ortopedia y Banco de Tejidos Musculoesqueléticos, Universidad de Santiago de Compostela, 15872 Santiago de Compostela (Spain); Dominguez, Fernando [Fundación Publica Galega de Medicina Xenómica, Santiago de Compostela (Spain); Sheikh, Faheem A.; Cantu, Travis; Desai, Raj; Garcia, Vanessa L. [Department of Chemistry, University of Texas Pan American, Edinburg, TX 78541 (United States); Macossay, Javier, E-mail: jmacossay@utpa.edu [Department of Chemistry, University of Texas Pan American, Edinburg, TX 78541 (United States)

2014-07-01

Biodegradable electrospun poly(ε-caprolactone) (PCL) scaffolds were coated with platelet-rich plasma (PRP) to improve cell adhesion and proliferation. PRP was obtained from human buffy coat, and tested on human adipose-derived mesenchymal stem cells (MSCs) to confirm cell proliferation and cytocompatibility. Then, PRP was adsorbed on the PCL scaffolds via lyophilization, which resulted in a uniform sponge-like coating of 2.85 (S.D. 0.14) mg/mg. The scaffolds were evaluated regarding mechanical properties (Young's modulus, tensile stress and tensile strain), sustained release of total protein and growth factors (PDGF-BB, TGF-β1 and VEGF), and hemocompatibility. MSC seeded on the PRP–PCL nanofibers showed an increased adhesion and proliferation compared to pristine PCL fibers. Moreover, the adsorbed PRP enabled angiogenesis features observed as neovascularization in a chicken chorioallantoic membrane (CAM) model. Overall, these results suggest that PRP–PCL scaffolds hold promise for tissue regeneration applications. - Highlights: • Platelet-rich plasma (PRP) can be adsorbed on electrospun fibers via lyophilization. • PRP coating enhanced mesenchymal stem cell adhesion and proliferation on scaffolds. • PRP-coated scaffolds showed sustained release of growth factors. • Adsorbed PRP provided angiogenic features. • PRP-poly(ε-caprolactone) scaffolds hold promise for tissue regeneration applications.

Merkel Cell Carcinoma: An Update of Key Imaging Techniques, Prognostic Factors, Treatment, and Follow-up.

Science.gov (United States)

Llombart, B; Kindem, S; Chust, M

2017-03-01

Merkel cell carcinoma, though rare, is one of the most aggressive tumors a dermatologist faces. More than a third of patients with this diagnosis die from the disease. Numerous researchers have attempted to identify clinical and pathologic predictors to guide prognosis, but their studies have produced inconsistent results. Because the incidence of Merkel cell carcinoma is low and it appears in patients of advanced age, prospective studies have not been done and no clear treatment algorithm has been developed. This review aims to provide an exhaustive, up-to-date account of Merkel cell carcinoma for the dermatologist. We describe prognostic factors and the imaging techniques that are most appropriate for evaluating disease spread. We also discuss current debates on treating Merkel cell carcinoma. Copyright © 2016 AEDV. Publicado por Elsevier España, S.L.U. All rights reserved.

Expansion and differentiation of germline-derived pluripotent stem cells on biomaterials.

Science.gov (United States)

Hoss, Mareike; Šarić, Tomo; Denecke, Bernd; Peinkofer, Gabriel; Bovi, Manfred; Groll, Jürgen; Ko, Kinarm; Salber, Jochen; Halbach, Marcel; Schöler, Hans R; Zenke, Martin; Neuss, Sabine

2013-05-01

Stem cells with broad differentiation potential, such as the recently described germline-derived pluripotent stem cells (gPS cells), are an appealing source for tissue engineering strategies. Biomaterials can inhibit, support, or induce proliferation and differentiation of stem cells. Here we identified (1) polymers that maintain self-renewal and differentiation potential of gPS cells for feeder-free expansion and (2) polymers supporting the cardiomyogenic fate of gPS cells by analyzing a panel of polymers of an established biomaterial bank previously used to assess growth of diverse stem cell types. Identification of cytocompatible gPS cell/biomaterial combinations required analysis of several parameters, including morphology, viability, cytotoxicity, apoptosis, proliferation, and differentiation potential. Pluripotency of gPS cells was visualized by the endogenous Oct4-promoter-driven GFP and by Sox2 and Nanog immunofluorescence. Viability assay, proliferation assay, and flow cytometry showed that gPS cells efficiently adhere and are viable on synthetic polymers, such as Resomer(®) LR704 (poly(L-lactic-D,L-lactic acid), poly(tetrafluor ethylene) (PTFE), poly(vinylidene fluoride) (PVDF), and on gelatine-coated tissue culture polystyrene. Expansion experiments showed that Resomer LR704 is an alternative substrate for feeder-free gPS cell maintenance. Resomer LR704, PTFE, and PVDF were found to be suitable for gPS cell differentiation. Spontaneous beating in embryoid bodies cultured on Resomer LR704 occurred already on day 8 of differentiation, much earlier compared to the other surfaces. This indicates that Resomer LR704 supports spontaneous cardiomyogenic differentiation of gPS cells, which was also confirmed on molecular, protein and functional level.

Suspension state increases reattachment of breast cancer cells by up-regulating lamin A/C.

Science.gov (United States)

Zhang, Xiaomei; Lv, Yonggang

2017-12-01

Extravasation is a rate-limiting step of tumor metastasis, for which adhesion to endothelium of circulating tumor cells (CTCs) is the prerequisite. The suspension state of CTCs undergoing detachment from primary tumor is a persistent biomechanical cue, which potentially regulates the biophysical characteristics and cellular behaviors of tumor cells. In this study, breast tumor cells MDA-MB-231 in suspension culture condition were used to investigate the effect of suspension state on reattachment of CTCs. Our study demonstrated that suspension state significantly increased the adhesion ability of breast tumor cells. In addition, suspension state markedly promoted the formation of stress fibers and focal adhesions and reduced the motility in reattached breast cancer cells. Moreover, lamin A/C was reversibly accumulated at posttranscriptional level under suspension state, improving the cell stiffness of reattached breast cancer cells. Disruption of actin cytoskeleton by cytochalasin D caused lamin A/C accumulation. Conversely, decreasing actomyosin contraction by ROCK inhibitor Y27632 reduced lamin A/C level. Knocking down lamin A/C weakened the suspension-induced increase of adhesion, and also abolished the suspension-induced decrease of motility and increase of stress fibers and focal adhesion in reattaching tumor cells, suggesting a crucial role of lamin A/C. In conclusion, it was demonstrated that suspension state promoted the reattachment of breast tumor cells by up-regulating lamin A/C via cytoskeleton disruption. These findings highlight the important role of suspension state for tumor cells in tumor metastasis. Copyright © 2017 Elsevier B.V. All rights reserved.

Biocompatible nanocomposite scaffolds based on copolymer-grafted chitosan for bone tissue engineering with drug delivery capability

International Nuclear Information System (INIS)

Saber-Samandari, Samaneh; Saber-Samandari, Saeed

2017-01-01

Significant efforts have been made to develop a suitable biocompatible scaffold for bone tissue engineering. In this work, a chitosan-graft-poly(acrylic acid-co-acrylamide)/hydroxyapatite nanocomposite scaffold was synthesized through a novel multi-step route. The prepared scaffolds were characterized for crystallinity, morphology, elemental analysis, chemical bonds, and pores size in their structure. The mechanical properties (i.e. compressive strength and elastic modulus) of the scaffolds were examined. Further, the biocompatibility of scaffolds was determined by MTT assays on HUGU cells. The result of cell culture experiments demonstrated that the prepared scaffolds have good cytocompatibility without any cytotoxicity, and with the incorporation of hydroxyapatite in their structure improves cell viability and proliferation. Finally, celecoxib as a model drug was efficiently loaded into the prepared scaffolds because of the large specific surface area. The in vitro release of the drug displayed a biphasic pattern with a low initial burst and a sustained release of up to 14 days. Furthermore, different release kinetic models were employed for the description of the release process. The results suggested that the prepared cytocompatible and non-toxic nanocomposite scaffolds might be efficient implants and drug carriers in bone-tissue engineering. - Highlights: • A series of biocompatible scaffolds were synthesized through a novel multi-step route. • The mechanical properties of the scaffolds were found close to those of trabecular bone. • The prepared scaffolds were able to load celecoxib efficiently as a model drug. • The celecoxib release was mainly controlled by a Fickian diffusion process. • The scaffold can be efficient as an implant for tissue engineering and drug delivery.

Biocompatible nanocomposite scaffolds based on copolymer-grafted chitosan for bone tissue engineering with drug delivery capability

Energy Technology Data Exchange (ETDEWEB)

Saber-Samandari, Samaneh, E-mail: samaneh.saber@gmail.com [Department of Chemistry, Eastern Mediterranean University, Gazimagusa, TRNC via Mersin 10 (Turkey); Saber-Samandari, Saeed, E-mail: saeedss@aut.ac.ir [New Technologies Research Center, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of)

2017-06-01

Significant efforts have been made to develop a suitable biocompatible scaffold for bone tissue engineering. In this work, a chitosan-graft-poly(acrylic acid-co-acrylamide)/hydroxyapatite nanocomposite scaffold was synthesized through a novel multi-step route. The prepared scaffolds were characterized for crystallinity, morphology, elemental analysis, chemical bonds, and pores size in their structure. The mechanical properties (i.e. compressive strength and elastic modulus) of the scaffolds were examined. Further, the biocompatibility of scaffolds was determined by MTT assays on HUGU cells. The result of cell culture experiments demonstrated that the prepared scaffolds have good cytocompatibility without any cytotoxicity, and with the incorporation of hydroxyapatite in their structure improves cell viability and proliferation. Finally, celecoxib as a model drug was efficiently loaded into the prepared scaffolds because of the large specific surface area. The in vitro release of the drug displayed a biphasic pattern with a low initial burst and a sustained release of up to 14 days. Furthermore, different release kinetic models were employed for the description of the release process. The results suggested that the prepared cytocompatible and non-toxic nanocomposite scaffolds might be efficient implants and drug carriers in bone-tissue engineering. - Highlights: • A series of biocompatible scaffolds were synthesized through a novel multi-step route. • The mechanical properties of the scaffolds were found close to those of trabecular bone. • The prepared scaffolds were able to load celecoxib efficiently as a model drug. • The celecoxib release was mainly controlled by a Fickian diffusion process. • The scaffold can be efficient as an implant for tissue engineering and drug delivery.

The effect of hirudin modification of silk fibroin on cell growth and antithrombogenicity

Energy Technology Data Exchange (ETDEWEB)

Wang, Qiongyu; Tu, Fangfang; Liu, Yunfei; Zhang, Yujin; Li, Helei; Kang, Zhao [National Engineering Laboratory for Modern Silk, College of Textile and Clothing Engineering, Soochow University, No. 199 Ren-ai Road, Suzhou Industrial Park, Suzhou, Jiangsu Province 215123 (China); Yin, Yin [Laboratory Animal Research Center, Soochow University, Suzhou, Jiangsu 215123 (China); Wang, Jiannan, E-mail: wangjn@suda.edu.cn [National Engineering Laboratory for Modern Silk, College of Textile and Clothing Engineering, Soochow University, No. 199 Ren-ai Road, Suzhou Industrial Park, Suzhou, Jiangsu Province 215123 (China)

2017-06-01

Thrombus formation remains a particular challenge for small-diameter vascular grafts. In this study, the direct thrombin inhibitor hirudin (Hir) was used to modify silk fibroin films in an attempt to enhance its antithrombogenic properties. Hir was successfully attached to silk fibroin and uniformly distributed in the regenerative material. Hir-modified films showed good cytocompatibility, and supported adhesion and proliferation of fibroblasts (L929), human umbilical vascular endothelial cells (HUVECs) and human aortic smooth muscle cells (HASMCs). Proliferation of HAVSMCs was inhibited by increasing Hir concentration. Activated partial thrombin time (APTT), prothrombin time (PT) and thrombin time (TT) of Hir-modified silk fibroin tubular scaffolds (SFTSs) were all increased markedly compared with fresh rabbit blood, ethanol-treated SFTS and unmodified SFTS, demonstrating the improved antithrombogenicity of SFTSs following modification with Hir. - Highlights: • A direct thrombin inhibitor hirudin was used to modify silk fibroin. • Antithrombogenic property of Hir-modified silk fibroin films was improved. • Hir-modified silk fibroin films supported adhesion and proliferation of HUVECs and HAVSMCs. • Proliferation of HAVSMCs on silk fibroin films was inhibited by increasing Hir concentration.

Up-regulation of granzyme B and perforin by staphylococcal enterotoxin C2 mutant induces enhanced cytotoxicity in Hepa1–6 cells

Energy Technology Data Exchange (ETDEWEB)

Zhang, Guojun [Institute of Applied Ecology, Chinese Academy of Sciences, No.72 Wenhua Road Shenhe Dis., Shenyang, Liaoning (China); University of Chinese Academy of Sciences, Beijing (China); Xu, Mingkai, E-mail: mkxu@iae.ac.cn [Institute of Applied Ecology, Chinese Academy of Sciences, No.72 Wenhua Road Shenhe Dis., Shenyang, Liaoning (China); Zhang, Huiwen [Institute of Applied Ecology, Chinese Academy of Sciences, No.72 Wenhua Road Shenhe Dis., Shenyang, Liaoning (China); Song, Yubo [Institute of Applied Ecology, Chinese Academy of Sciences, No.72 Wenhua Road Shenhe Dis., Shenyang, Liaoning (China); University of Chinese Academy of Sciences, Beijing (China); Wang, Jian; Zhang, Chenggang [Institute of Applied Ecology, Chinese Academy of Sciences, No.72 Wenhua Road Shenhe Dis., Shenyang, Liaoning (China)

2016-12-15

Staphylococcal enterotoxin C2 (SEC2), a member of bacterial superantigen, is one of the most potent known activators of T lymphocytes. With this property, SEC2 has already been used in clinic as a tumor immunotherapy agent in China. To increase the antitumor activity, a SEC2 mutant named ST-4 (GKVTG102-106WWH) with amino acid substitutions in T cell receptor (TCR)-binding domain was generated by site-directed mutagenesis, and the molecular mechanism of the enhanced antitumor activity was investigated. Results showed that ST-4 could activate much more Vβ 8.2 and 8.3 T cells and NK cells compared with SEC2, and exhibited significantly enhanced immunocyte stimulation and antitumor activity in vitro. The synthetic peptide sequencing the residues of mutant TCR-binding domain could competitively inhibit the immunocyte stimulation activity of ST-4. Most importantly, ST-4 up-regulated granzyme B and perforin at both mRNA and protein levels. We also found that expression of proapoptotic proteins cytochrome c, BAX and activation of caspase-3, 9 was up-regulated, and antiapoptotic protein Bcl-xL was down-regulated in the treatment with either ST-4 or SEC2. When granzyme B inhibitor or perforin inhibitor is presented, tumor cell viability was significantly rescued. Taken together, we demonstrate that increased ST-4-TCR recognition contributed to massive T cells and NK cells activation. These activated cells released up-regulated granzyme B and perforin, which induced the enhanced tumor cells apoptosis by mitochondrial apoptotic pathway, and ultimately led to enhanced tumor cell growth inhibition. ST-4 may be a promising candidate for antitumor clinic usage in future. - Highlights: • We obtained a SEC2 mutant ST-4 with enhanced superantigen and antitumor activity. • Increased ST-4-TCR recognition contributed to massive T cells and NK cells activation. • Up-regulated GzmB and PRF1 in T cell by ST-4 induced enhanced tumor cells apoptosis. • Enhanced tumor cell apoptosis

Novel strontium-doped bioactive glass nanoparticles enhance proliferation and osteogenic differentiation of human bone marrow stromal cells

Energy Technology Data Exchange (ETDEWEB)

Strobel, L. A. [University of Erlangen-Nuremberg Medical Center, Department of Plastic and Hand Surgery (Germany); Hild, N.; Mohn, D.; Stark, W. J. [ETH Zurich, Department of Chemistry and Applied Biosciences, Institute for Chemical and Bioengineering (Switzerland); Hoppe, A. [University of Erlangen-Nuremberg, Department of Materials Science and Engineering, Institute of Biomaterials (Germany); Gbureck, U. [University of Wuerzburg, Department for Functional Materials in Medicine and Dentistry (Germany); Horch, R. E.; Kneser, U. [University of Erlangen-Nuremberg Medical Center, Department of Plastic and Hand Surgery (Germany); Boccaccini, A. R., E-mail: aldo.boccaccini@ww.uni-erlangen.de [University of Erlangen-Nuremberg, Department of Materials Science and Engineering, Institute of Biomaterials (Germany)

2013-07-15

The present study investigates a new family of bioactive glass nanoparticles with and without Sr-doping focusing on the influence of the nanoparticles on human bone marrow stromal cells (hBMSCs) in vitro. The bioactive glass nanoparticles were fabricated by flame spray synthesis and a particle diameter of 30-35 nm was achieved. Glass nanoparticles were undoped (BG 13-93-0Sr) or doped with 5 wt% strontium (Sr) (BG 13-93-5Sr) and used at concentrations of 10 and 100 {mu}g/cm Superscript-Two (particles per culture plate area), respectively. Cells were cultured for 14 days after which the samples were analysed regarding metabolic activity and expression of various bone-specific genes. Cell growth and morphology indicated the high cytocompatibility of the nanoparticulate bioactive glass. The presence of the nanoparticles enhanced cell growth compared to the plain polystyrene control group. At a concentration of 100 {mu}g/cm Superscript-Two , Sr-doped particles led to significantly enhanced gene expression of osteocalcin, collagen type 1 and vascular endothelial growth factor. Thus, Sr-doped nanoparticles showing a dose-dependent increase of osteogenic differentiation in hBMSCs are a promising biomaterial for bone regeneration purposes.

Novel strontium-doped bioactive glass nanoparticles enhance proliferation and osteogenic differentiation of human bone marrow stromal cells

International Nuclear Information System (INIS)

Strobel, L. A.; Hild, N.; Mohn, D.; Stark, W. J.; Hoppe, A.; Gbureck, U.; Horch, R. E.; Kneser, U.; Boccaccini, A. R.

2013-01-01

The present study investigates a new family of bioactive glass nanoparticles with and without Sr-doping focusing on the influence of the nanoparticles on human bone marrow stromal cells (hBMSCs) in vitro. The bioactive glass nanoparticles were fabricated by flame spray synthesis and a particle diameter of 30–35 nm was achieved. Glass nanoparticles were undoped (BG 13-93-0Sr) or doped with 5 wt% strontium (Sr) (BG 13-93-5Sr) and used at concentrations of 10 and 100 μg/cm² (particles per culture plate area), respectively. Cells were cultured for 14 days after which the samples were analysed regarding metabolic activity and expression of various bone-specific genes. Cell growth and morphology indicated the high cytocompatibility of the nanoparticulate bioactive glass. The presence of the nanoparticles enhanced cell growth compared to the plain polystyrene control group. At a concentration of 100 μg/cm², Sr-doped particles led to significantly enhanced gene expression of osteocalcin, collagen type 1 and vascular endothelial growth factor. Thus, Sr-doped nanoparticles showing a dose-dependent increase of osteogenic differentiation in hBMSCs are a promising biomaterial for bone regeneration purposes

Novel strontium-doped bioactive glass nanoparticles enhance proliferation and osteogenic differentiation of human bone marrow stromal cells

Science.gov (United States)

Strobel, L. A.; Hild, N.; Mohn, D.; Stark, W. J.; Hoppe, A.; Gbureck, U.; Horch, R. E.; Kneser, U.; Boccaccini, A. R.

2013-07-01

The present study investigates a new family of bioactive glass nanoparticles with and without Sr-doping focusing on the influence of the nanoparticles on human bone marrow stromal cells (hBMSCs) in vitro. The bioactive glass nanoparticles were fabricated by flame spray synthesis and a particle diameter of 30-35 nm was achieved. Glass nanoparticles were undoped (BG 13-93-0Sr) or doped with 5 wt% strontium (Sr) (BG 13-93-5Sr) and used at concentrations of 10 and 100 μg/cm² (particles per culture plate area), respectively. Cells were cultured for 14 days after which the samples were analysed regarding metabolic activity and expression of various bone-specific genes. Cell growth and morphology indicated the high cytocompatibility of the nanoparticulate bioactive glass. The presence of the nanoparticles enhanced cell growth compared to the plain polystyrene control group. At a concentration of 100 μg/cm², Sr-doped particles led to significantly enhanced gene expression of osteocalcin, collagen type 1 and vascular endothelial growth factor. Thus, Sr-doped nanoparticles showing a dose-dependent increase of osteogenic differentiation in hBMSCs are a promising biomaterial for bone regeneration purposes.

Reducing gravity takes the bounce out of running.

Science.gov (United States)

Polet, Delyle T; Schroeder, Ryan T; Bertram, John E A

2018-02-13

In gravity below Earth-normal, a person should be able to take higher leaps in running. We asked 10 subjects to run on a treadmill in five levels of simulated reduced gravity and optically tracked centre-of-mass kinematics. Subjects consistently reduced ballistic height compared with running in normal gravity. We explain this trend by considering the vertical take-off velocity (defined as maximum vertical velocity). Energetically optimal gaits should balance the energetic costs of ground-contact collisions (favouring lower take-off velocity), and step frequency penalties such as leg swing work (favouring higher take-off velocity, but less so in reduced gravity). Measured vertical take-off velocity scaled with the square root of gravitational acceleration, following energetic optimality predictions and explaining why ballistic height decreases in lower gravity. The success of work-based costs in predicting this behaviour challenges the notion that gait adaptation in reduced gravity results from an unloading of the stance phase. Only the relationship between take-off velocity and swing cost changes in reduced gravity; the energetic cost of the down-to-up transition for a given vertical take-off velocity does not change with gravity. Because lower gravity allows an elongated swing phase for a given take-off velocity, the motor control system can relax the vertical momentum change in the stance phase, thus reducing ballistic height, without great energetic penalty to leg swing work. Although it may seem counterintuitive, using less 'bouncy' gaits in reduced gravity is a strategy to reduce energetic costs, to which humans seem extremely sensitive. © 2018. Published by The Company of Biologists Ltd.

FOXO3-mediated up-regulation of Bim contributes to rhein-induced cancer cell apoptosis.

Science.gov (United States)

Wang, Jiao; Liu, Shu; Yin, Yancun; Li, Mingjin; Wang, Bo; Yang, Li; Jiang, Yangfu

2015-03-01

The anthraquinone compound rhein is a natural agent in the traditional Chinese medicine rhubarb. Preclinical studies demonstrate that rhein has anticancer activity. Treatment of a variety of cancer cells with rhein may induce apoptosis. Here, we report that rhein induces atypical unfolded protein response in breast cancer MCF-7 cells and hepatoma HepG2 cells. Rhein induces CHOP expression, eIF2α phosphorylation and caspase cleavage, while it does not induce glucose-regulated protein 78 (GRP78) expression in both MCF-7 and HepG2 cells. Meanwhile, rhein inhibits thapsigargin-induced GRP78 expression and X box-binding protein 1 splicing. In addition, rhein inhibits Akt phosphorylation and stimulates FOXO transactivation activity. Rhein induces Bim expression in MCF-7 and HepG2 cells, which can be abrogated by FOXO3a knockdown. Knockdown of FOXO3a or Bim abrogates rhein-induced caspase cleavage and apoptosis. The chemical chaperone 4-phenylbutyrate acid antagonizes the induction of FOXO activation, Bim expression and caspase cleavage by rhein, indicating that protein misfolding may be involved in triggering these deleterious effects. We conclude that FOXO3a-mediated up-regulation of Bim is a key mechanism underlying rhein-induced cancer cells apoptosis.

Up-Regulation of P21 Inhibits TRAIL-Mediated Extrinsic Apoptosis, Contributing Resistance to SAHA in Acute Myeloid Leukemia Cells

Directory of Open Access Journals (Sweden)

Xing Wu

2014-08-01

Full Text Available Background/Aim: P21, a multifunctional cell cycle-regulatory molecule, regulates apoptotic cell death. In this study we examined the effect of altered p21 expression on the sensitivity of acute myeloid leukemia cells in response to HDAC inhibitor SAHA treatment and investigated the underlying mechanism. Methods: Stably transfected HL60 cell lines were established in RPMI-1640 with supplementation of G-418. Cell viability was measured by MTT assay. Western blot was applied to assess the protein expression levels of target genes. Cell apoptosis was monitored by AnnexinV-PE/7AAD assay. Results: We showed HL60 cells that that didn't up-regulate p21 expression were more sensitive to SAHA-mediated apoptosis than NB4 and U937 cells that had increased p21 level. Enforced expression of p21 in HL60 cells reduced sensitivity to SAHA and blocked TRAIL-mediated apoptosis. Conversely, p21 silencing in NB4 cells enhanced SAHA-mediated apoptosis and lethality. Finally, we found that combined treatment with SAHA and rapamycin down-regulated p21 and enhanced apoptosis in AML cells. Conclusion: We conclude that up-regulated p21 expression mediates resistance to SAHA via inhibition of TRAIL apoptotic pathway. P21 may serve as a candidate biomarker to predict responsiveness or resistance to SAHA-based therapy in AML patients. In addition, rapamycin may be an effective agent to override p21-mediated resistance to SAHA in AML patients.

Extracellular creatine regulates creatine transport in rat and human muscle cells.

OpenAIRE

Loike, J D; Zalutsky, D L; Kaback, E; Miranda, A F; Silverstein, S C

1988-01-01

Muscle cells do not synthesize creatine; they take up exogenous creatine by specific Na+-dependent plasma membrane transporters. We found that extracellular creatine regulates the level of expression of these creatine transporters in L6 rat muscle cells. L6 myoblasts maintained for 24 hr in medium containing 1 mM creatine exhibited 1/3rd of the creatine transport activity of cells maintained for 24 hr in medium without creatine. Down-regulation of creatine transport was partially reversed whe...

Mannose receptor induces T-cell tolerance via inhibition of CD45 and up-regulation of CTLA-4.

Science.gov (United States)

Schuette, Verena; Embgenbroich, Maria; Ulas, Thomas; Welz, Meike; Schulte-Schrepping, Jonas; Draffehn, Astrid M; Quast, Thomas; Koch, Katharina; Nehring, Melanie; König, Jessica; Zweynert, Annegret; Harms, Frederike L; Steiner, Nancy; Limmer, Andreas; Förster, Irmgard; Berberich-Siebelt, Friederike; Knolle, Percy A; Wohlleber, Dirk; Kolanus, Waldemar; Beyer, Marc; Schultze, Joachim L; Burgdorf, Sven

2016-09-20

The mannose receptor (MR) is an endocytic receptor involved in serum homeostasis and antigen presentation. Here, we identify the MR as a direct regulator of CD8(+) T-cell activity. We demonstrate that MR expression on dendritic cells (DCs) impaired T-cell cytotoxicity in vitro and in vivo. This regulatory effect of the MR was mediated by a direct interaction with CD45 on the T cell, inhibiting its phosphatase activity, which resulted in up-regulation of cytotoxic T-lymphocyte-associated Protein 4 (CTLA-4) and the induction of T-cell tolerance. Inhibition of CD45 prevented expression of B-cell lymphoma 6 (Bcl-6), a transcriptional inhibitor that directly bound the CTLA-4 promoter and regulated its activity. These data demonstrate that endocytic receptors expressed on DCs contribute to the regulation of T-cell functionality.

Influence of layer-by-layer assembled electrospun poly (L-lactic acid) nanofiber mats on the bioactivity of endothelial cells

Science.gov (United States)

Wu, Keke; Zhang, Xiazhi; Yang, Wufeng; Liu, Xiaoyan; Jiao, Yanpeng; Zhou, Changren

2016-12-01

Electrospun poly(L-lactic acid) (PLLA) nanofiber mats were successfully modified by deposition of multilayers with chitosan (CS), heparin (Hep) and graphene oxide (GO) through electrostatic layer-by-layer (LBL) self-assembly method. In this study, the surface properties of PLLA nanofiber mats before and after modification were investigated via scanning electron microscope (SEM), atomic force microscopy (AFM), attenuated total reflectance fourier transformation infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and water contact angle measurement. In addition, the cytocompatibility of the modified PLLA nanofiber mats were investigated by testing endothelial cells compatibility, including cell attachment, cell proliferation and cell cycle. The results revealed that the surfaces of modified PLLA nanofiber mats become much rougher, stifiness and the hydrophilicity of the LBL modified PLLA nanofiber mats were improved compared to original PLLA one. Moreover, the modified PLLA nanofiber mats had promoted the endothelial cells viability attachment significantly. Besides, we studied the PLLA nanofiber mats on the expression of necrosis factor (TNF-α), interleukine-1β (IL-1β), monocyte chemoattractant protein-1 (MCP-1) and vascular cell adhesion molecule-1 (VCAM-1) in endothelial cells. The results showed that modified PLLA nanofiber mats had inhibited the inflammatory response to some extent.

Irradiation-induced up-regulation of HLA-E on macrovascular endothelial cells confers protection against killing by activated natural killer cells.

Directory of Open Access Journals (Sweden)

Isabelle Riederer

-induced, transient up-regulation of HLA-E on macrovascular ECs might confer protection against NK cell-mediated vascular injury.

Interakce kmenových buněk s polymerním substrátem

Czech Academy of Sciences Publication Activity Database

Kasálková-Slepičková, N.; Slepička, P.; Bačáková, Lucie; Kolská, Z.; Švorčík, V.

2017-01-01

Roč. 111, č. 7 (2017), s. 439-444 ISSN 0009-2770 R&D Projects: GA MZd(CZ) NV15-33018A Institutional support: RVO:67985823 Keywords : polymer * plasma * surface modification * cytocompatibility * stem cells Subject RIV: EI - Biotechnology ; Bionics OBOR OECD: Technologies involving the manipulation of cells, tissues, organs or the whole organism (assisted reproduction) Impact factor: 0.387, year: 2016

Taking into account the binding effects in positronium

International Nuclear Information System (INIS)

Tyukhtyaev, Yu.N.

1978-01-01

In order to take into acount the binding of particles in quantum electrodynamics, the Coulomb Green function at all stages of constructing the quasipotential is used. For the first time in the quasipotential approach the contribution of the possitronium ground state splitting from the one-photon direct diagram is calculated up to the α 6 lnα terms

How we make cell therapy in Italy

Directory of Open Access Journals (Sweden)

Montemurro T

2015-08-01

Full Text Available Tiziana Montemurro, Mariele Viganò, Silvia Budelli, Elisa Montelatici, Cristiana Lavazza, Luigi Marino, Valentina Parazzi, Lorenza Lazzari, Rosaria GiordanoCell Factory, Unit of Cell Therapy and Cryobiology, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milano, ItalyAbstract: In the 21st century scenario, new therapeutic tools are needed to take up the social and medical challenge posed by the more and more frequent degenerative disorders and by the aging of population. The recent category of advanced therapy medicinal products has been created to comprise cellular, gene therapy, and tissue engineered products, as a new class of drugs. Their manufacture requires the same pharmaceutical framework as for conventional drugs and this means that industrial, large-scale manufacturing process has to be adapted to the peculiar characteristics of cell-containing products. Our hospital took up the challenge of this new path in the early 2000s; and herein we describe the approach we followed to set up a pharmaceutical-grade facility in a public hospital context, with the aim to share the solutions we found to make cell therapy compliant with the requirements for the production and the quality control of a high-standard medicinal product.Keywords: advanced therapy medicinal product, good manufacturing practices, stem cells

Ceramide-induced TCR up-regulation

DEFF Research Database (Denmark)

Menné, C; Lauritsen, Jens Peter Holst; Dietrich, J

2000-01-01

to increase T cell responsiveness. The purpose of this study was to identify and characterize potential pathways for TCR up-regulation. We found that ceramide affected TCR recycling dynamics and induced TCR up-regulation in a concentration- and time-dependent manner. Experiments applying phosphatase......The TCR is a constitutively recycling receptor meaning that a constant fraction of TCR from the plasma membrane is transported inside the cell at the same time as a constant fraction of TCR from the intracellular pool is transported to the plasma membrane. TCR recycling is affected by protein...... kinase C activity. Thus, an increase in protein kinase C activity affects TCR recycling kinetics leading to a new TCR equilibrium with a reduced level of TCR expressed at the T cell surface. Down-regulation of TCR expression compromises T cell activation. Conversely, TCR up-regulation is expected...

Up-regulation of Store-operated Ca2+ Entry and Nuclear Factor of Activated T Cells Promote the Acinar Phenotype of the Primary Human Salivary Gland Cells*

Science.gov (United States)

Jang, Shyh-Ing; Ong, Hwei Ling; Liu, Xibao; Alevizos, Ilias; Ambudkar, Indu S.

2016-01-01

The signaling pathways involved in the generation and maintenance of exocrine gland acinar cells have not yet been established. Primary human salivary gland epithelial cells, derived from salivary gland biopsies, acquired an acinar-like phenotype when the [Ca2+] in the serum-free medium (keratinocyte growth medium, KGM) was increased from 0.05 mm (KGM-L) to 1.2 mm (KGM-H). Here we examined the mechanism underlying this Ca2+-dependent generation of the acinar cell phenotype. Compared with cells in KGM-L, those in KGM-H display enhancement of Orai1, STIM1, STIM2, and nuclear factor of activated T cells 1 (NFAT1) expression together with an increase in store-operated Ca2+ entry (SOCE), SOCE-dependent nuclear translocation of pGFP-NFAT1, and NFAT-dependent but not NFκB-dependent gene expression. Importantly, AQP5, an acinar-specific protein critical for function, is up-regulated in KGM-H via SOCE/NFAT-dependent gene expression. We identified critical NFAT binding motifs in the AQP5 promoter that are involved in Ca2+-dependent up-regulation of AQP5. These important findings reveal that the Ca2+-induced switch of salivary epithelial cells to an acinar-like phenotype involves remodeling of SOCE and NFAT signaling, which together control the expression of proteins critically relevant for acinar cell function. Our data provide a novel strategy for generating and maintaining acinar cells in culture. PMID:26903518

Histone deacetylase inhibitors up-regulate LL-37 expression independent of toll-like receptor mediated signalling in airway epithelial cells.

Science.gov (United States)

Liu, Quan; Liu, Juan; Roschmann, Kristina Irene Lisolette; van Egmond, Danielle; Golebski, Korneliusz; Fokkens, Wytske Johanna; Wang, Dehui; van Drunen, Cornelis Maria

2013-04-11

HDAC inhibitors have been proposed as anticancer agents. However, their roles in innate genes expression remain not well known. Cathelicidin LL-37 is one of the few human bactericidal peptides, but the regulation of histone acetylation on LL-37 expression in airway epithelium remains largely unknown. Therefore, we investigated the effects of two non-selective HDACi, trichostatin A (TSA) and sodium butyrate (SB), on the expression of the cathelicidin LL-37 in human airway epithelial cells. LL37 in human NCI-H292 airway epithelial cells and the primary cultures of normal nasal epithelial cells(PNEC) in response to HDAC inhibitors with or without poly (I:C) stimulation was assessed using real-time PCR and western blot. In parallel, IL-6 expression was evaluated by ELISA. Our results showed that HDAC inhibitors up-regulated LL-37 gene expression independent of poly (I:C) stimulation in PNEC as well as in NCI-H292 cells. HDAC inhibitors increased LL37 protein expression in NCI-H292 cells but not in PNEC. In addition, HDAC inhibitors significantly inhibited poly (I:C)-induced IL-6 production in both of the epithelial cells. In conclusion, HDAC inhibitors directly up-regulated LL-37 gene expression in human airway epithelial cells.

Hypoxia promotes Mycobacterium tuberculosis-specific up-regulation of granulysin in human T cells.

Science.gov (United States)

Zenk, Sebastian F; Vollmer, Michael; Schercher, Esra; Kallert, Stephanie; Kubis, Jan; Stenger, Steffen

2016-06-01

Oxygen tension affects local immune responses in inflammation and infection. In tuberculosis mycobacteria avoid hypoxic areas and preferentially persist and reactivate in the oxygen-rich apex of the lung. Oxygen restriction activates antimicrobial effector mechanisms in macrophages and restricts growth of intracellular Mycobacterium tuberculosis (M.Tb). The effect of oxygen restriction on T cell-mediated antimicrobial effector mechanisms is unknown. Therefore we determined the influence of hypoxia on the expression of granulysin, an antimicrobial peptide of lymphocytes. Hypoxia increased the antigen-specific up-regulation of granulysin mRNA and protein in human CD4(+) and CD8(+) T lymphocytes. This observation was functionally relevant, because oxygen restriction supported the growth-limiting effect of antigen-specific T cells against virulent M.Tb residing in primary human macrophages. Our results provide evidence that oxygen restriction promotes the expression of granulysin and suggest that this effect-in conjunction with additional T cell-mediated immune responses-supports protection against mycobacteria. The therapeutic modulation of oxygen availability may offer a new strategy for the host-directed therapy of infectious diseases with intracellular pathogens.

Stem Cell Spheroids and Ex Vivo Niche Modeling: Rationalization and Scaling-Up.

Science.gov (United States)

Chimenti, Isotta; Massai, Diana; Morbiducci, Umberto; Beltrami, Antonio Paolo; Pesce, Maurizio; Messina, Elisa

2017-04-01

Improved protocols/devices for in vitro culture of 3D cell spheroids may provide essential cues for proper growth and differentiation of stem/progenitor cells (S/PCs) in their niche, allowing preservation of specific features, such as multi-lineage potential and paracrine activity. Several platforms have been employed to replicate these conditions and to generate S/PC spheroids for therapeutic applications. However, they incompletely reproduce the niche environment, with partial loss of its highly regulated network, with additional hurdles in the field of cardiac biology, due to debated resident S/PCs therapeutic potential and clinical translation. In this contribution, the essential niche conditions (metabolic, geometric, mechanical) that allow S/PCs maintenance/commitment will be discussed. In particular, we will focus on both existing bioreactor-based platforms for the culture of S/PC as spheroids, and on possible criteria for the scaling-up of niche-like spheroids, which could be envisaged as promising tools for personalized cardiac regenerative medicine, as well as for high-throughput drug screening.

Toll-like receptor 3 signalling up-regulates expression of the HIV co-receptor G-protein coupled receptor 15 on human CD4+ T cells.

Directory of Open Access Journals (Sweden)

Miriam Kiene

Full Text Available BACKGROUND: Many HIV-2 and SIV isolates, as well as some HIV-1 strains, can use the orphan 7-transmembrane receptor GPR15 as co-receptor for efficient entry into host cells. GPR15 is expressed on central memory and effector memory CD4(+ T cells in healthy individuals and a subset of these cells is susceptible to HIV-1 and SIV infection. However, it has not been determined whether GPR15 expression is altered in the context of HIV-1 infection. RESULTS: Here, we show that GPR15 expression in CD4(+ T cells is markedly up-regulated in some HIV-1 infected individuals compared to the rest of the infected patients and to healthy controls. Infection of the PM1 T cell line with primary HIV-1 isolates was found to up-regulate GPR15 expression on the infected cells, indicating that viral components can induce GPR15 expression. Up-regulation of GPR15 expression on CD4(+ T cells was induced by activation of Toll-like receptor 3 signalling via TIR-domain-containing adapter-inducing interferon-β (TRIF and was more prominent on gut-homing compared to lymph node-homing CD4(+ T cells. CONCLUSION: These results suggest that infection-induced up-regulation of GPR15 expression could increase susceptibility of CD4(+ T cells to HIV infection and target cell availability in the gut in some infected individuals.

Construction of membrane-bound artificial cells using microfluidics: a new frontier in bottom-up synthetic biology.

Science.gov (United States)

Elani, Yuval

2016-06-15

The quest to construct artificial cells from the bottom-up using simple building blocks has received much attention over recent decades and is one of the grand challenges in synthetic biology. Cell mimics that are encapsulated by lipid membranes are a particularly powerful class of artificial cells due to their biocompatibility and the ability to reconstitute biological machinery within them. One of the key obstacles in the field centres on the following: how can membrane-based artificial cells be generated in a controlled way and in high-throughput? In particular, how can they be constructed to have precisely defined parameters including size, biomolecular composition and spatial organization? Microfluidic generation strategies have proved instrumental in addressing these questions. This article will outline some of the major principles underpinning membrane-based artificial cells and their construction using microfluidics, and will detail some recent landmarks that have been achieved. © 2016 The Author(s).

Tissues from equine cadaver ligaments up to 72 hours of post-mortem: a promising reservoir of stem cells.

Science.gov (United States)

Shikh Alsook, Mohamad Khir; Gabriel, Annick; Piret, Joëlle; Waroux, Olivier; Tonus, Céline; Connan, Delphine; Baise, Etienne; Antoine, Nadine

2015-12-18

Mesenchymal stem cells (MSCs) harvested from cadaveric tissues represent a promising approach for regenerative medicine. To date, no study has investigated whether viable MSCs could survive in cadaveric tissues from tendon or ligament up to 72 hours of post-mortem. The purpose of the present work was to find out if viable MSCs could survive in cadaveric tissues from adult equine ligaments up to 72 hours of post-mortem, and to assess their ability (i) to remain in an undifferentiated state and (ii) to divide and proliferate in the absence of any specific stimulus. MSCs were isolated from equine cadaver (EC) suspensory ligaments within 48-72 hours of post-mortem. They were evaluated for viability, proliferation, capacity for tri-lineage differentiation, expression of cell surface markers (CD90, CD105, CD73, CD45), pluripotent transcription factor (OCT-4), stage-specific embryonic antigen-1 (SSEA-1), neuron-specific class III beta-tubulin (TUJ-1), and glial fibrillary acidic protein (GFAP). As well, they were characterized by transmission electron microscope (TEM). EC-MSCs were successfully isolated and maintained for 20 passages with high cell viability and proliferation. Phase contrast microscopy revealed that cells with fibroblast-like appearance were predominant in the culture. Differentiation assays proved that EC-MSCs are able to differentiate towards mesodermal lineages (osteogenic, adipogenic, chondrogenic). Flow cytometry analysis demonstrated that EC-MSCs expressed CD90, CD105, and CD73, while being negative for the leukocyte common antigen CD45. Immunofluorescence analysis showed a high percentage of positive cells for OCT-4 and SSEA-1. Surprisingly, in absence of any stimuli, some adherent cells closely resembling neuronal and glial morphology were also observed. Interestingly, our results revealed that approximately 15 % of the cell populations were TUJ-1 positive, whereas GFAP expression was detected in only a few cells. Furthermore, TEM analysis

Influence of non-thermal TiCl{sub 4}/Ar + O{sub 2} plasma-assisted TiOx based coatings on the surface of polypropylene (PP) films for the tailoring of surface properties and cytocompatibility

Energy Technology Data Exchange (ETDEWEB)

Pandiyaraj, K.N., E-mail: dr.knpr@gmail.com [Surface Engineering Laboratory, Department of Physics, Sri Shakthi Institute of Engineering and Technology, L& T by pass, Chinniyam Palayam (post), Coimbatore 641062 (India); Kumar, A. Arun; Ramkumar, M.C. [Surface Engineering Laboratory, Department of Physics, Sri Shakthi Institute of Engineering and Technology, L& T by pass, Chinniyam Palayam (post), Coimbatore 641062 (India); Sachdev, A.; Gopinath, P. [Nanobiotechnology Laboratory, Centre for Nanotechnology, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand 247667 (India); Cools, Pieter; De Geyter, N.; Morent, R. [Research Unit Plasma Technology (RUPT), Department of Applied Physics, Faculty of Engineering and Architecture, Ghent University, Jozef Plateaustraat 22, 9000 Gent (Belgium); Deshmukh, R.R. [Department of Physics, Institute of Chemical Technology, Matunga, Mumbai 400 019 (India); Hegde, P. [William Mason High School, Mason 45040 (United States); Han, C. [Department of Biomedical, Chemical and Environmental Engineering, University of Cincinnati, Cincinnati, OH 45221-0012 (United States); Nadagouda, M.N. [Center for Nanoscale Multifunctional Materials, Wright State University, Dayton, OH 45435 (United States)

2016-05-01

The superior bulk properties (corrosion resistance, high strength to weight ratio, relatively low cost and easy processing) of hydrocarbon based polymers such as polypropylene (PP) have contributed significantly to the development of new biomedical applications such as artificial organs and cell scaffolds. However, low cell affinity is one of the main draw backs for PP due to its poor surface properties. In tissue engineering, physico-chemical surface properties such as hydrophilicity, polar functional groups, surface charge and morphology play a crucial role to enrich the cell proliferation and adhesion. In this present investigation TiOx based biocompatible coatings were developed on the surface of PP films via DC excited glow discharge plasma, using TiCl{sub 4}/Ar + O{sub 2} gas mixture as a precursor. Various TiOx-based coatings are deposited on the surface of PP films as a function of discharge power. The changes in hydrophilicity of the TiO{sub x}/PP film surfaces were studied using contact angle analysis and surface energy calculations by Fowke's approximation. X-ray photo-electron spectroscopy (XPS) was used to investigate the surface chemical composition of TiOx/PP films. The surface morphology of the obtained TiO{sub x}/PP films was investigated by scanning electron and transmission electron microscopy (SEM &TEM). Moreover, the surface topography of the material was analyzed by atomic force microscopy (AFM). The cytocompatibility of the TiO{sub x}/PP films was investigated via in vitro analysis (cell viability, adhesion and cytotoxicity) using NIH3T3 (mouse embryonic fibroblast) cells. Furthermore the antibacterial activities of TiO{sub x}/PP films were also evaluated against two distinct bacterial models namely Gram positive Staphylococcus aureus (S.aureus) and Gram negative Escherichia coli DH5α. (E.coli) bacteria. XPS results clearly indicate the successful incorporation of TiO{sub x} and oxygen containing polar functional groups on the surface

Live-cell super-resolution imaging of intrinsically fast moving flagellates

Science.gov (United States)

Glogger, M.; Stichler, S.; Subota, I.; Bertlein, S.; Spindler, M.-C.; Teßmar, J.; Groll, J.; Engstler, M.; Fenz, S. F.

2017-02-01

Recent developments in super-resolution microscopy make it possible to resolve structures in biological cells at a spatial resolution of a few nm and observe dynamical processes with a temporal resolution of ms to μs. However, the optimal structural resolution requires repeated illumination cycles and is thus limited to chemically fixed cells. For live cell applications substantial improvement over classical Abbe-limited imaging can already be obtained in adherent or slow moving cells. Nonetheless, a large group of cells are fast moving and thus could not yet be addressed with live cell super-resolution microscopy. These include flagellate pathogens like African trypanosomes, the causative agents of sleeping sickness in humans and nagana in livestock. Here, we present an embedding method based on a in situ forming cytocompatible UV-crosslinked hydrogel. The fast cross-linking hydrogel immobilizes trypanosomes efficiently to allow microscopy on the nanoscale. We characterized both the trypanosomes and the hydrogel with respect to their autofluorescence properties and found them suitable for single-molecule fluorescence microscopy (SMFM). As a proof of principle, SMFM was applied to super-resolve a structure inside the living trypanosome. We present an image of a flagellar axoneme component recorded by using the intrinsic blinking behavior of eYFP. , which features invited work from the best early-career researchers working within the scope of J Phys D. This project is part of the Journal of Physics series’ 50th anniversary celebrations in 2017. Susanne Fenz was selected by the Editorial Board of J Phys D as an Emerging Talent/Leader.

Synthesis and Cell Seeding Assessment of Novel Biphasic Nano Powder in the CaO–MgO–SiO2 System for Bone Implant Application

Directory of Open Access Journals (Sweden)

Kazem Marzban

2017-02-01

Full Text Available Objective(s: CaO–MgO–SiO2 system bioceramics possess good characteristics for hard tissue engineering applications. The aim of the study was to synthesize the nano powder by using a sol-gel method and evaluate of bioactivity in the cells culture. Methods: To characterize of powder X-ray diffraction (XRD, transmission electron microscopy (TEM and to evaluate the bioactivity sample cell seeding and methylthiazol tetrazolium (MTT assay were performed. Results: X-ray diffraction (XRD analysis showed that the biphasic powder was obtained at 1300°C for 2 h by using a sol-gel method. Transmission electron microscopy (TEM image showed that powder particle size was about 45 nm. Besides, cell culture results indicated that the percentage of viability values was increased by the extension of period. Conclusions: found that the sample is cytocompatible and has cell proliferation potential in culture medium. The present study demonstrates that, the biphasic CaO–MgO–SiO2 system can be used to achieve novel bioactive materials for bone implant application.

A Long-Term Follow-Up Study of Allogeneic Mesenchymal Stem/Stromal Cell Transplantation in Patients with Drug-Resistant Systemic Lupus Erythematosus

Directory of Open Access Journals (Sweden)

Dandan Wang

2018-03-01

Full Text Available Summary: Allogeneic mesenchymal stem/stromal cells (MSCs have been widely studied as an alternative cell source for regenerative medicine. Here, we report a long-term follow-up study of allogeneic bone marrow and/or umbilical cord MSC transplantation (MSCT in severe and drug-refractory systemic lupus erythematosus (SLE patients. Eighty-one patients were enrolled, and the 5-year overall survival rate was 84% (68/81 after MSCT. At 5-year follow-up, 27% of patients (22/81 were in complete clinical remission and another 7% (6/81 were in partial clinical remission, with a 5-year disease remission rate of 34% (28/81. In total, 37 patients had achieved clinical remission and then 9 patients subsequently relapsed, with 5-year overall rate of relapse of 24% (9/37. SLE Disease Activity Index scores, serum albumin, complement C3, peripheral white blood cell, and platelet numbers, as well as proteinuria levels, continued to improve during the follow-up. Our results demonstrated that allogeneic MSCT is safe and resulted in long-term clinical remission in SLE patients. : In this article, Sun and colleagues show that allogeneic bone marrow and/or umbilical cord-derived mesenchymal stem/stromal cell transplantation both result in good clinical safety and effect in treating drug-refractory systemic lupus erythematosus patients, by introducing a 5- to 8-year follow-up study for all the 81 enrolled patients. Keywords: bone marrow, mesenchymal stem cells, systemic lupus erythematosus, safety, umbilical cord

In vitro bioactivity and cytocompatibility of tricalcium silicate

Indian Academy of Sciences (India)

tricalcium silicate powder showed that it could induce bone- like apatite formation after ... ated by soaking them in SBF, cell adhesion and MTT assay, respectively. 2. .... tibility, which might be used as one of the bioactive coating materials and ...

"Muddying the Clear Waters": Teachers' Take-up of the Linguistic Idea of Revoicing

Science.gov (United States)

Herbel-Eisenmann, Beth; Drake, Corey; Cirillo, Michelle

2009-01-01

This article examines a collaborative study group's discussions about "revoicing," an idea from linguistics that has been identified as an important discourse strategy in the teaching of mathematics as well as other content areas. This group, made up of eight middle grades (grades 6-10) mathematics teacher-researchers (TRs), one university…

Strategies for merging microbial fuel cell technologies in water desalination processes: Start-up protocol and desalination efficiency assessment

Science.gov (United States)

Borjas, Zulema; Esteve-Núñez, Abraham; Ortiz, Juan Manuel

2017-07-01

Microbial Desalination Cells constitute an innovative technology where microbial fuel cell and electrodialysis merge in the same device for obtaining fresh water from saline water with no energy-associated cost for the user. In this work, an anodic biofilm of the electroactive bacteria Geobacter sulfurreducens was able to efficiently convert the acetate present in synthetic waste water into electric current (j = 0.32 mA cm-2) able to desalinate water. .Moreover, we implemented an efficient start-up protocol where desalination up to 90% occurred in a desalination cycle (water production:0.308 L m-2 h-1, initial salinity: 9 mS cm-1, final salinity: osmosis (RO) or reverse electrodialysis.

Investigation of low-cost oligoanthraquinones for alkaline, aqueous rechargeable batteries with cell potential up to 1.13 V

Science.gov (United States)

Dražević, Emil; Andersen, Anders Søndergaard; Wedege, Kristina; Henriksen, Martin Lahn; Hinge, Mogens; Bentien, Anders

2018-03-01

The transition to renewable energy sources has created need for stationary, low-cost electrical energy storage. A possible technology to address both cost and environmental concerns are batteries based on organic materials. The use of oligoanthraquinones as a replacement for metal hydrides or cadmium in nickel hydroxide rechargeable batteries is investigated in detail regarding polymer composition, electrochemical reversibility and electroactive species cost. Two different oligoanthraquinones are paired with a nickel hydroxide cathode and demonstrate cycling stability dependent on parameters such as supporting electrolyte strength, C-rate, and anode swelling. The energy efficiencies are up to 75% and the cell potential up to 1.13 V. Simple functionalization of the basic structure increases the cell potential by 100 mV.

Colour bio-factories: Towards scale-up production of anthocyanins in plant cell cultures.

Science.gov (United States)

Appelhagen, Ingo; Wulff-Vester, Anders Keim; Wendell, Micael; Hvoslef-Eide, Anne-Kathrine; Russell, Julia; Oertel, Anne; Martens, Stefan; Mock, Hans-Peter; Martin, Cathie; Matros, Andrea

2018-06-08

Anthocyanins are widely distributed, glycosylated, water-soluble plant pigments, which give many fruits and flowers their red, purple or blue colouration. Their beneficial effects in a dietary context have encouraged increasing use of anthocyanins as natural colourants in the food and cosmetic industries. However, the limited availability and diversity of anthocyanins commercially have initiated searches for alternative sources of these natural colourants. In plants, high-level production of secondary metabolites, such as anthocyanins, can be achieved by engineering of regulatory genes as well as genes encoding biosynthetic enzymes. We have used tobacco lines which constitutively produce high levels of cyanidin 3-O-rutinoside, delphinidin 3-O-rutinoside or a novel anthocyanin, acylated cyanidin 3-O-(coumaroyl) rutinoside to generate cell suspension cultures. The cell lines are stable in their production rates and superior to conventional plant cell cultures. Scale-up of anthocyanin production in small scale fermenters has been demonstrated. The cell cultures have also proven to be a suitable system for production of 13 C-labelled anthocyanins. Our method for anthocyanin production is transferable to other plant species, such as Arabidopsis thaliana, demonstrating the potential of this approach for making a wide range of highly-decorated anthocyanins. The tobacco cell cultures represent a customisable and sustainable alternative to conventional anthocyanin production platforms and have considerable potential for use in industrial and medical applications of anthocyanins. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

Follow-up strategies in head and neck cancer other than upper aerodigestive tract squamous cell carcinoma

NARCIS (Netherlands)

Digonnet, Antoine; Hamoir, Marc; Andry, Guy; Vander Poorten, Vincent; Haigentz, Missak; Langendijk, Johannes A.; de Bree, Remco; Hinni, Michael L.; Mendenhall, William M.; Paleri, Vinidh; Rinaldo, Alessandra; Werner, Jochen A.; Takes, Robert P.; Ferlito, Alfio

Post-therapy follow-up for patients with head and neck cancer other than upper aerodigestive tract squamous cell carcinoma should meet several objectives: to detect both local, regional or distant recurrences, to evaluate acute and long-term treatment-related side effects, to guide the

Recent advances in engineering topography mediated antibacterial surfaces

Science.gov (United States)

Hasan, Jafar; Chatterjee, Kaushik

2015-09-01

The tendency of bacterial cells to adhere and colonize a material surface leading to biofilm formation is a fundamental challenge underlying many different applications including microbial infections associated with biomedical devices and products. Although, bacterial attachment to surfaces has been extensively studied in the past, the effect of surface topography on bacteria-material interactions has received little attention until more recently. We review the recent progress in surface topography based approaches for engineering antibacterial surfaces. Biomimicry of antibacterial surfaces in nature is a popular strategy. Whereas earlier endeavors in the field aimed at minimizing cell attachment, more recent efforts have focused on developing bactericidal surfaces. However, not all such topography mediated bactericidal surfaces are necessarily cytocompatible thus underscoring the need for continued efforts for research in this area for developing antibacterial and yet cytocompatible surfaces for use in implantable biomedical applications. This mini-review provides a brief overview of the current strategies and challenges in the emerging field of topography mediated antibacterial surfaces.

Preparation and in vitro evaluation of nanostructured TiO2/TCP composite coating by plasma electrolytic oxidation

International Nuclear Information System (INIS)

Hu, Hongjie; Liu, Xuanyong; Ding, Chuanxian

2010-01-01

Porous and nanostructured TiO 2 /tricalcium phosphate (TCP) composite coating on titanium substrate was prepared by plasma electrolytic oxidation (PEO). The microstructure and phase composition of the coating were characterized using scanning electron microscopy and X-ray diffraction. Its bioactivity was evaluated by simulated body fluid (SBF) immersion tests. MG63 cells were cultured on the surface of the coating to investigate its cytocompatibility. Potentiodynamic polarization tests were applied to measure its corrosion resistance. The results revealed that rough and hydrophilic TiO 2 /TCP composite coating with pores of several micrometers and grains of 50-200 nm was prepared by one-step PEO treatment. The TiO 2 /TCP composite coating showed good apatite-forming ability in SBF, and the TCP phase in the coating played an important role in inducing apatite formation. MG63 cells could adhere and proliferate on the surface of the coating, indicating its good cytocompatibility. The composite coating also exhibited good corrosion resistance in 0.9% NaCl solution.

Taking antacids

Science.gov (United States)

Heartburn - antacids; Reflux - antacids; GERD - antacids ... Antacids are a good treatment for heartburn that occurs once in a while. Take antacids about 1 hour after eating or when you have heartburn. If you are taking ...

Cell-in-Shell Hybrids: Chemical Nanoencapsulation of Individual Cells.

Science.gov (United States)

Park, Ji Hun; Hong, Daewha; Lee, Juno; Choi, Insung S

2016-05-17

Nature has developed a fascinating strategy of cryptobiosis ("secret life") for counteracting the stressful, and often lethal, environmental conditions that fluctuate sporadically over time. For example, certain bacteria sporulate to transform from a metabolically active, vegetative state to an ametabolic endospore state. The bacterial endospores, encased within tough biomolecular shells, withstand the extremes of harmful stressors, such as radiation, desiccation, and malnutrition, for extended periods of time and return to a vegetative state by breaking their protective shells apart when their environment becomes hospitable for living. Certain ciliates and even higher organisms, for example, tardigrades, and others are also found to adopt a cryptobiotic strategy for survival. A common feature of cryptobiosis is the structural presence of tough sheaths on cellular structures. However, most cells and cellular assemblies are not "spore-forming" and are vulnerable to the outside threats. In particular, mammalian cells, enclosed with labile lipid bilayers, are highly susceptible to in vitro conditions in the laboratory and daily life settings, making manipulation and preservation difficult outside of specialized conditions. The instability of living cells has been a main bottleneck to the advanced development of cell-based applications, such as cell therapy and cell-based sensors. A judicious question arises: can cellular tolerance against harmful stresses be enhanced by simply forming cell-in-shell hybrid structures? Experimental results suggest that the answer is yes. A micrometer-sized "Iron Man" can be generated by chemically forming an ultrathin (cell. Since the report on silica nanoencapsulation of yeast cells, in which cytoprotective yeast-in-silica hybrids were formed, several synthetic strategies have been developed to encapsulate individual cells in a cytocompatible fashion, mimicking the cryptobiotic cell-in-shell structures found in nature, for example

Taking warfarin (Coumadin)

Science.gov (United States)

... page: //medlineplus.gov/ency/patientinstructions/000292.htm Taking warfarin (Coumadin) To use the sharing features on this ... form a clot or have bleeding problems. Taking Warfarin It is important that you take warfarin exactly ...

Take Charge. Take the Test. PSA (:30)

Centers for Disease Control (CDC) Podcasts

2012-03-07

As part of the Take Charge. Take the Test. campaign, this 30 second PSA encourages African American women to get tested for HIV. Locations for a free HIV test can be found by visiting hivtest.org/takecharge or calling 1-800-CDC-INFO (1-800-232-4636).  Created: 3/7/2012 by National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention (NCHHSTP).   Date Released: 3/7/2012.

Up-regulation of Store-operated Ca2+ Entry and Nuclear Factor of Activated T Cells Promote the Acinar Phenotype of the Primary Human Salivary Gland Cells.

Science.gov (United States)

Jang, Shyh-Ing; Ong, Hwei Ling; Liu, Xibao; Alevizos, Ilias; Ambudkar, Indu S

2016-04-15

The signaling pathways involved in the generation and maintenance of exocrine gland acinar cells have not yet been established. Primary human salivary gland epithelial cells, derived from salivary gland biopsies, acquired an acinar-like phenotype when the [Ca(2+)] in the serum-free medium (keratinocyte growth medium, KGM) was increased from 0.05 mm (KGM-L) to 1.2 mm (KGM-H). Here we examined the mechanism underlying this Ca(2+)-dependent generation of the acinar cell phenotype. Compared with cells in KGM-L, those in KGM-H display enhancement of Orai1, STIM1, STIM2, and nuclear factor of activated T cells 1 (NFAT1) expression together with an increase in store-operated Ca(2+) entry (SOCE), SOCE-dependent nuclear translocation of pGFP-NFAT1, and NFAT-dependent but not NFκB-dependent gene expression. Importantly, AQP5, an acinar-specific protein critical for function, is up-regulated in KGM-H via SOCE/NFAT-dependent gene expression. We identified critical NFAT binding motifs in the AQP5 promoter that are involved in Ca(2+)-dependent up-regulation of AQP5. These important findings reveal that the Ca(2+)-induced switch of salivary epithelial cells to an acinar-like phenotype involves remodeling of SOCE and NFAT signaling, which together control the expression of proteins critically relevant for acinar cell function. Our data provide a novel strategy for generating and maintaining acinar cells in culture. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Chitosan hydrogels enriched with polyphenols: Antibacterial activity, cell adhesion and growth and mineralization

Czech Academy of Sciences Publication Activity Database

Lišková, Jana; Douglas, T.E.L.; Beranová, J.; Skwarczyńska, A.; Božič, M.; Samal, S. K.; Modrzejewska, Z.; Gorgieva, S.; Kokol, V.; Bačáková, Lucie

2015-01-01

Roč. 129, Sep 20 (2015), s. 135-142 ISSN 0144-8617 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0109; GA MŠk(CZ) EE2.3.30.0025 Institutional support: RVO:67985823 Keywords : hydrogel * polyphenol * cytocompatibility Subject RIV: EI - Biotechnology ; Bionics Impact factor: 4.219, year: 2015

Three-year follow-up of sentinel node-negative patients with early oral cavity squamous cell carcinoma

DEFF Research Database (Denmark)

Sebbesen, Lars; Bilde, Anders; Therkildsen, Marianne

2014-01-01

2009, 53 consecutive SNB-negative patients with oral cavity squamous cell carcinoma (SCC) T1 to T2 were accrued. Follow-up was done continuously with the most recent examination in October 2011. The location of the sentinel lymph nodes was determined using dynamic and planar lymphoscintigraphy...

Note Taking on Trial: A Legal Application of Note-Taking Research

Science.gov (United States)

Kiewra, Kenneth A.

2016-01-01

This article is about note taking, but it is not an exhaustive review of note-taking literature. Instead, it portrays the application of note-taking research to an unusual and important area of practice--the law. I was hired to serve as an expert witness on note taking in a legal case that hinged, in part, on the completeness and accuracy of…

Lactobacillus casei Exerts Anti-Proliferative Effects Accompanied by Apoptotic Cell Death and Up-Regulation of TRAIL in Colon Carcinoma Cells

Science.gov (United States)

Santarmaki, Valentina; Aindelis, Georgios; Tompoulidou, Evgenia; Lamprianidou, Eleftheria E.; Saxami, Georgia; Ypsilantis, Petros; Lampri, Evangeli S.; Simopoulos, Constantinos; Kotsianidis, Ioannis; Galanis, Alex; Kourkoutas, Yiannis; Dimitrellou, Dimitra; Chlichlia, Katerina

2016-01-01

Probiotic microorganisms such as lactic acid bacteria (LAB) exert a number of strain-specific health-promoting activities attributed to their immunomodulatory, anti-inflammatory and anti-carcinogenic properties. Despite recent attention, our understanding of the biological processes involved in the beneficial effects of LAB strains is still limited. To this end, the present study investigated the growth-inhibitory effects of Lactobacillus casei ATCC 393 against experimental colon cancer. Administration of live Lactobacillus casei (as well as bacterial components thereof) on murine (CT26) and human (HT29) colon carcinoma cell lines raised a significant concentration- and time-dependent anti-proliferative effect, determined by cell viability assays. Specifically, a dramatic decrease in viability of colon cancer cells co-incubated with 109 CFU/mL L. casei for 24 hours was detected (78% for HT29 and 52% for CT26 cells). In addition, live L. casei induced apoptotic cell death in both cell lines as revealed by annexin V and propidium iodide staining. The significance of the in vitro anti-proliferative effects was further confirmed in an experimental tumor model. Oral daily administration of 109 CFU live L. casei for 13 days significantly inhibited in vivo growth of colon carcinoma cells, resulting in approximately 80% reduction in tumor volume of treated mice. Tumor growth inhibition was accompanied by L. casei-driven up-regulation of the TNF-related apoptosis-inducing ligand TRAIL and down-regulation of Survivin. Taken together, these findings provide evidence for beneficial tumor-inhibitory, anti-proliferative and pro-apoptotic effects driven by this probiotic LAB strain. PMID:26849051

Lactobacillus casei Exerts Anti-Proliferative Effects Accompanied by Apoptotic Cell Death and Up-Regulation of TRAIL in Colon Carcinoma Cells.

Directory of Open Access Journals (Sweden)

Angeliki Tiptiri-Kourpeti

Full Text Available Probiotic microorganisms such as lactic acid bacteria (LAB exert a number of strain-specific health-promoting activities attributed to their immunomodulatory, anti-inflammatory and anti-carcinogenic properties. Despite recent attention, our understanding of the biological processes involved in the beneficial effects of LAB strains is still limited. To this end, the present study investigated the growth-inhibitory effects of Lactobacillus casei ATCC 393 against experimental colon cancer. Administration of live Lactobacillus casei (as well as bacterial components thereof on murine (CT26 and human (HT29 colon carcinoma cell lines raised a significant concentration- and time-dependent anti-proliferative effect, determined by cell viability assays. Specifically, a dramatic decrease in viability of colon cancer cells co-incubated with 10(9 CFU/mL L. casei for 24 hours was detected (78% for HT29 and 52% for CT26 cells. In addition, live L. casei induced apoptotic cell death in both cell lines as revealed by annexin V and propidium iodide staining. The significance of the in vitro anti-proliferative effects was further confirmed in an experimental tumor model. Oral daily administration of 10(9 CFU live L. casei for 13 days significantly inhibited in vivo growth of colon carcinoma cells, resulting in approximately 80% reduction in tumor volume of treated mice. Tumor growth inhibition was accompanied by L. casei-driven up-regulation of the TNF-related apoptosis-inducing ligand TRAIL and down-regulation of Survivin. Taken together, these findings provide evidence for beneficial tumor-inhibitory, anti-proliferative and pro-apoptotic effects driven by this probiotic LAB strain.

Lactobacillus casei Exerts Anti-Proliferative Effects Accompanied by Apoptotic Cell Death and Up-Regulation of TRAIL in Colon Carcinoma Cells.

Science.gov (United States)

Tiptiri-Kourpeti, Angeliki; Spyridopoulou, Katerina; Santarmaki, Valentina; Aindelis, Georgios; Tompoulidou, Evgenia; Lamprianidou, Eleftheria E; Saxami, Georgia; Ypsilantis, Petros; Lampri, Evangeli S; Simopoulos, Constantinos; Kotsianidis, Ioannis; Galanis, Alex; Kourkoutas, Yiannis; Dimitrellou, Dimitra; Chlichlia, Katerina

2016-01-01

Probiotic microorganisms such as lactic acid bacteria (LAB) exert a number of strain-specific health-promoting activities attributed to their immunomodulatory, anti-inflammatory and anti-carcinogenic properties. Despite recent attention, our understanding of the biological processes involved in the beneficial effects of LAB strains is still limited. To this end, the present study investigated the growth-inhibitory effects of Lactobacillus casei ATCC 393 against experimental colon cancer. Administration of live Lactobacillus casei (as well as bacterial components thereof) on murine (CT26) and human (HT29) colon carcinoma cell lines raised a significant concentration- and time-dependent anti-proliferative effect, determined by cell viability assays. Specifically, a dramatic decrease in viability of colon cancer cells co-incubated with 10(9) CFU/mL L. casei for 24 hours was detected (78% for HT29 and 52% for CT26 cells). In addition, live L. casei induced apoptotic cell death in both cell lines as revealed by annexin V and propidium iodide staining. The significance of the in vitro anti-proliferative effects was further confirmed in an experimental tumor model. Oral daily administration of 10(9) CFU live L. casei for 13 days significantly inhibited in vivo growth of colon carcinoma cells, resulting in approximately 80% reduction in tumor volume of treated mice. Tumor growth inhibition was accompanied by L. casei-driven up-regulation of the TNF-related apoptosis-inducing ligand TRAIL and down-regulation of Survivin. Taken together, these findings provide evidence for beneficial tumor-inhibitory, anti-proliferative and pro-apoptotic effects driven by this probiotic LAB strain.

An in vivo model to assess magnesium alloys and their biological effect on human bone marrow stromal cells.

Science.gov (United States)

Yoshizawa, Sayuri; Chaya, Amy; Verdelis, Kostas; Bilodeau, Elizabeth A; Sfeir, Charles

2015-12-01

Magnesium (Mg) alloys have many unique qualities which make them ideal candidates for bone fixation devices, including biocompatibility and degradation in vivo. Despite a rise in Mg alloy production and research, there remains no standardized system to assess their degradation or biological effect on human stem cells in vivo. In this study, we developed a novel in vivo model to assess Mg alloys for craniofacial and orthopedic applications. Our model consists of a collagen sponge seeded with human bone marrow stromal cells (hBMSCs) around a central Mg alloy rod. These scaffolds were implanted subcutaneously in mice and analyzed after eight weeks. Alloy degradation and biological effect were determined by microcomputed tomography (microCT), histological staining, and immunohistochemistry (IHC). MicroCT showed greater volume loss for pure Mg compared to AZ31 after eight weeks in vivo. Histological analysis showed that hBMSCs were retained around the Mg implants after 8 weeks. Furthermore, immunohistochemistry showed the expression of dentin matrix protein 1 and osteopontin around both pure Mg and AZ31 with implanted hBMSCs. In addition, histological sections showed a thin mineral layer around all degrading alloys at the alloy-tissue interface. In conclusion, our data show that degrading pure Mg and AZ31 implants are cytocompatible and do not inhibit the osteogenic property of hBMSCs in vivo. These results demonstrate that this model can be used to efficiently assess the biological effect of corroding Mg alloys in vivo. Importantly, this model may be modified to accommodate additional cell types and clinical applications. Magnesium (Mg) alloys have been investigated as ideal candidates for bone fixation devices due to high biocompatibility and degradation in vivo, and there is a growing need of establishing an efficient in vivo material screening system. In this study, we assessed degradation rate and biological effect of Mg alloys by transplanting Mg alloy rod with

Biphasic calcium sulfate dihydrate/iron-modified alpha-tricalcium phosphate bone cement for spinal applications: in vitro study

International Nuclear Information System (INIS)

Vlad, M D; Lopez, J; Torres, R; Barraco, M; Fernandez, E; Valle, L J; Poeata, I

2010-01-01

In this study, the cytocompatibility of new 'iron-modified/alpha-tricalcium phosphate (IM/α-TCP) and calcium sulfate dihydrate (CSD)' bone cement (IM/α-TCP/CSD-BC) intended for spinal applications has been approached. The objective was to investigate by direct-contact osteoblast-like cell cultures (from 1 to 14 days) the in vitro cell adhesion, proliferation, morphology and cytoskeleton organization of MG-63 cells seeded onto the new cements. The results were as follows: (a) quantitative MTT-assay and scanning electron microscopy (SEM) showed that cell adhesion, proliferation and viability were not affected with time by the presence of iron in the cements; (b) double immunofluorescent labeling of F-actin and α-tubulin showed a dynamic interaction between the cell and its porous substrates sustaining the locomotion phenomenon on the cements' surface, which favored the colonization, and confirming the biocompatibility of the experimental cements; (c) SEM-cell morphology and cytoskeleton observations also evidenced that MG-63 cells were able to adhere, to spread and to attain normal morphology on the new IM/α-TCP/CSD-BC which offered favorable substratum properties for osteoblast-like cells proliferation and differentiation in vitro. The results showed that these new iron-modified cement-like biomaterials have cytocompatible features of interest not only as possible spinal cancellous bone replacement biomaterial but also as bone tissue engineering scaffolds.

How we make cell therapy in Italy.

Science.gov (United States)

Montemurro, Tiziana; Viganò, Mariele; Budelli, Silvia; Montelatici, Elisa; Lavazza, Cristiana; Marino, Luigi; Parazzi, Valentina; Lazzari, Lorenza; Giordano, Rosaria

2015-01-01

In the 21st century scenario, new therapeutic tools are needed to take up the social and medical challenge posed by the more and more frequent degenerative disorders and by the aging of population. The recent category of advanced therapy medicinal products has been created to comprise cellular, gene therapy, and tissue engineered products, as a new class of drugs. Their manufacture requires the same pharmaceutical framework as for conventional drugs and this means that industrial, large-scale manufacturing process has to be adapted to the peculiar characteristics of cell-containing products. Our hospital took up the challenge of this new path in the early 2000s; and herein we describe the approach we followed to set up a pharmaceutical-grade facility in a public hospital context, with the aim to share the solutions we found to make cell therapy compliant with the requirements for the production and the quality control of a high-standard medicinal product.

Hydroxypropyl cellulose methacrylate as a photo-patternable and biodegradable hybrid paper substrate for cell culture and other bioapplications.

Science.gov (United States)

Qi, Aisha; Hoo, Siew Pei; Friend, James; Yeo, Leslie; Yue, Zhilian; Chan, Peggy P Y

2014-04-01

In addition to the choice of appropriate material properties of the tissue construct to be used, such as its biocompatibility, biodegradability, cytocompatibility, and mechanical rigidity, the ability to incorporate microarchitectural patterns in the construct to mimic that found in the cellular microenvironment is an important consideration in tissue engineering and regenerative medicine. Both these issues are addressed by demonstrating a method for preparing biodegradable and photo-patternable constructs, where modified cellulose is cross-linked to form an insoluble structure in an aqueous environment. Specifically, hydroxypropyl cellulose (HPC) is rendered photocrosslinkable by grafting with methylacrylic anhydride, whose linkages also render the cross-linked construct hydrolytically degradable. The HPC is then cross-linked via a photolithography-based fabrication process. The feasibility of functionalizing these HPC structures with biochemical cues is verified post-fabrication, and shown to facilitate the adhesion of mesenchymal progenitor cells. The HPC constructs are shown to be biocompatible and hydrolytically degradable, thus enabling cell proliferation and cell migration, and therefore constituting an ideal candidate for long-term cell culture and implantable tissue scaffold applications. In addition, the potential of the HPC structure is demonstrated as an alternative substrate to paper microfluidic diagnostic devices for protein and cell assays. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Taking Your iPad 2 to the Max

CERN Document Server

Sadun, Erica; Sande, Steve

2011-01-01

iPad 2: It looks different. It acts different. It connects to the world, yet it is as personal as a well-worn book. And now it has two cameras!. Taking Your iPad 2 to the Max is written so that anyone can quickly get up to speed on Apple's latest hit. As bloggers at The Unofficial Apple Weblog (TUAW.com), the authors have the happy privilege of working with Apple products every day, and they'll guide you through all of the perks of being an iPad 2 owner. This book takes you from selecting and buying an iPad, to connecting it to the Internet, to using the incredible power of the iPad and all it

DAQExpert - An expert system to increase CMS data-taking efficiency

CERN Document Server

Andre, Jean-marc Olivier; Branson, James; Chaze, Olivier; Cittolin, Sergio; Contescu, Cristian; Darlea, Georgiana Lavinia; Deldicque, Christian; Demiragli, Zeynep; Dobson, Marc; Doualot, Nicolas; Erhan, Samim; Fulcher, Jonathan Richard; Gigi, Dominique; Gladki, Maciej Szymon; Glege, Frank; Gomez Ceballos, Guillelmo; Hegeman, Jeroen Guido; Holzner, Andre Georg; Janulis, Mindaugas; Lettrich, Michael; Meijers, Franciscus; Meschi, Emilio; Mommsen, Remigius; Morovic, Srecko; O'Dell, Vivian; Orn, Samuel Johan; Orsini, Luciano; Papakrivopoulos, Ioannis; Paus, Christoph Maria Ernst; Petrova, Petia; Petrucci, Andrea; Pieri, Marco; Rabady, Dinyar Sebastian; Racz, Attila; Reis, Thomas; Sakulin, Hannes; Schwick, Christoph; Simelevicius, Dainius; Vougioukas, Michail; Zejdl, Petr

2017-01-01

The efficiency of the Data Acquisition (DAQ) of the Compact Muon Solenoid (CMS) experiment for LHC Run 2 is constantly being improved. A~significant factor affecting the data taking efficiency is the experience of the DAQ operator. One of the main responsibilities of the DAQ operator is to carry out the proper recovery procedure in case of failure of data-taking. At the start of Run 2, understanding the problem and finding the right remedy could take a considerable amount of time (up to many minutes). Operators heavily relied on the support of on-call experts, also outside working hours. Wrong decisions due to time pressure sometimes lead to an additional overhead in recovery time. To increase the efficiency of CMS data-taking we developed a new expert system, the DAQExpert, which provides shifters with optimal recovery suggestions instantly when a failure occurs. DAQExpert is a~web application analyzing frequently updating monitoring data from all DAQ components and identifying problems based on expert knowl...

Study on cell survival, induction of apoptosis and micronucleus formation in SCL-II and RTiV3 cells after exposure to the Auger electron emitter Tc-99m

International Nuclear Information System (INIS)

Kadenbach, K.; Kriehuber, R.; Weiss, D.G.

2003-01-01

Full text: Cell survival, induction of apoptosis and micronucleus (MN) formation have been investigated in the human squamous cell carcinoma cell line SCL-II and in the rat tracheal cell line RTiV3 after exposure to the Auger electron emitter Tc-99m. Cells were either acutely gamma(Co-60)-irradiated (0.78 Gy/min) or exposed to Tc-99m-Pertechnetate (25-300 MBq/20ml) for 24 h under cell culture conditions and assayed for cell survival (Colony-forming assay), micronucleus formation (Cytochalasin B assay) and the frequency of apoptotic cells (Fluorescence microscopy). Analytical dosimetrical models have been applied to derive the absorbed dose corresponding to the accumulated decays of Tc-99m. Absorbed doses up to 1.3 Gy could be achieved after Tc-99m exposure leading to no significant cell killing in this dose range except at one dose point (0.25 Gy) in SCL-II cells. MN formation was consistently lower when compared to Co-60 irradiated cells and showed a linear dose-response. The apoptotic response in SCL-II cells after Tc-99m exposure was described best by a 3rd order polynomial and increased apoptosis induction could be observed at much lower doses (0.25 Gy) in comparison to the reference radiation (0.8 Gy). The relative biological effectiveness (RBE) has been determined for MN formation and apoptosis induction and was found to be in the range of 0.1- 1.3 for both investigated biological endpoints, depending on which mathematical model for describing the dose-effect curve was used. Up-take experiments revealed an activity concentration ratio cells vs. medium of 1.2 after 16 h up to 24 h of exposure. No increased biological effectiveness of Tc-99m applied as Sodium-Pertechnetate could be observed in the investigated cell lines in comparison to gamma-irradiation. Induction of apoptosis is slightly increased after Tc-99m exposure in SCL-II cells and it has to be further evaluated, if this is due to the emitted Auger-component. A passive up-take mechanism of Tc-99m is

Revving up natural killer cells and cytokine-induced killer cells against hematological malignancies

Directory of Open Access Journals (Sweden)

Gianfranco ePittari

2015-05-01

Full Text Available Natural killer (NK cells belong to innate immunity and exhibit cytolytic activity against infectious pathogens and tumor cells. NK-cell function is finely tuned by receptors that transduce inhibitory or activating signals, such as killer immunoglobulin-like receptors (KIR, NK Group 2 member D (NKG2D, NKG2A/CD94, NKp46 and others, and recognize both foreign and self-antigens expressed by NK-susceptible targets. Recent insights into NK-cell developmental intermediates have translated into a more accurate definition of culture conditions for the in vitro generation and propagation of human NK cells. In this respect, interleukin (IL-15 and IL-21 are instrumental in driving NK-cell differentiation and maturation, and hold great promise for the design of optimal NK-cell culture protocols.Cytokine-induced killer (CIK cells possess phenotypic and functional hallmarks of both T cells and NK cells. Similar to T cells, they express CD3 and are expandable in culture, while not requiring functional priming for in vivo activity, like NK cells. CIK cells may offer some advantages over other cell therapy products, including ease of in vitro propagation and no need for exogenous administration of IL-2 for in vivo priming.NK cells and CIK cells can be expanded using a variety of clinical-grade approaches, before their infusion into patients with cancer. Herein, we discuss GMP-compliant strategies to isolate and expand human NK and CIK cells for immunotherapy purposes, focusing on clinical trials of adoptive transfer to patients with hematological malignancies.

Revving up Natural Killer Cells and Cytokine-Induced Killer Cells Against Hematological Malignancies.

Science.gov (United States)

Pittari, Gianfranco; Filippini, Perla; Gentilcore, Giusy; Grivel, Jean-Charles; Rutella, Sergio

2015-01-01

Natural killer (NK) cells belong to innate immunity and exhibit cytolytic activity against infectious pathogens and tumor cells. NK-cell function is finely tuned by receptors that transduce inhibitory or activating signals, such as killer immunoglobulin-like receptors, NK Group 2 member D (NKG2D), NKG2A/CD94, NKp46, and others, and recognize both foreign and self-antigens expressed by NK-susceptible targets. Recent insights into NK-cell developmental intermediates have translated into a more accurate definition of culture conditions for the in vitro generation and propagation of human NK cells. In this respect, interleukin (IL)-15 and IL-21 are instrumental in driving NK-cell differentiation and maturation, and hold great promise for the design of optimal NK-cell culture protocols. Cytokine-induced killer (CIK) cells possess phenotypic and functional hallmarks of both T cells and NK cells. Similar to T cells, they express CD3 and are expandable in culture, while not requiring functional priming for in vivo activity, like NK cells. CIK cells may offer some advantages over other cell therapy products, including ease of in vitro propagation and no need for exogenous administration of IL-2 for in vivo priming. NK cells and CIK cells can be expanded using a variety of clinical-grade approaches, before their infusion into patients with cancer. Herein, we discuss GMP-compliant strategies to isolate and expand human NK and CIK cells for immunotherapy purposes, focusing on clinical trials of adoptive transfer to patients with hematological malignancies.

Cytotoxicity and Bioactivity of Calcium Silicate Cements Combined with Niobium Oxide in Different Cell Lines.

Science.gov (United States)

Mestieri, Leticia Boldrin; Gomes-Cornélio, Ana Lívia; Rodrigues, Elisandra Márcia; Faria, Gisele; Guerreiro-Tanomaru, Juliane Maria; Tanomaru-Filho, Mário

2017-01-01

The aim of this study was to evaluate the cytotoxicity and bioactivity of calcium silicate-based cements combined with niobium oxide (Nb2O5) micro and nanoparticles, comparing the response in different cell lines. This evaluation used four cell lines: two primary cultures (human dental pulp cells - hDPCs and human dental follicle cells - hDFCs) and two immortalized cultures (human osteoblast-like cells - Saos-2 and mouse periodontal ligament cells - mPDL). The tested materials were: White Portland Cement (PC), mineral trioxide aggregate (MTA), white Portland cement combined with microparticles (PC/Nb2O5µ) or nanoparticles (PC/Nb2O5n) of niobium oxide (Nb2O5). Cytotoxicity was evaluated by the methylthiazolyldiphenyl-tetrazolium bromide (MTT) and trypan blue exclusion assays and bioactivity by alkaline phosphatase (ALP) enzyme activity. Results were analyzed by ANOVA and Tukey test (a=0.05). PC/Nb2O5n presented similar or higher cell viability than PC/Nb2O5µ in all cell lines. Moreover, the materials presented similar or higher cell viability than MTA. Saos-2 exhibited high ALP activity, highlighting PC/Nb2O5µ material at 7 days of exposure. In conclusion, calcium silicate cements combined with micro and nanoparticles of Nb2O5 presented cytocompatibility and bioactivity, demonstrating the potential of Nb2O5 as an alternative radiopacifier agent for these cements. The different cell lines had similar response to cytotoxicity evaluation of calcium silicate cements. However, bioactivity was more accurately detected in human osteoblast-like cell line, Saos-2.

Description of the Tile Calorimeter noise with increasing Pile-up for $\\sqrt{s}=7\\,\\rm{TeV}$ data collected during 2011

CERN Document Server

The ATLAS collaboration

2016-01-01

In this note the noise in the Tile calorimeter is investigated with special attention to the pile-up effect. A full survey of the TileCal cells is performed, based both on pseudorapidity, bunch position in a train and number of interactions per bunch crossing. Several periods of 2011 data collected by the ATLAS experiment at $\\sqrt{s}=7\\,\\rm{TeV}$ were used in the analysis. Just one run from each data-taking period corresponding to different pile-up conditions was examined. The data were recorded by zero bias trigger. The Monte Carlo simulation was reweighted to the pile-up conditions of the data. This study contributes to a better knowledge of the Tile Calorimeter response and performance under increasing pile-up conditions.

Platelet rich plasma promotes skeletal muscle cell migration in association with up-regulation of FAK, paxillin, and F-Actin formation.

Science.gov (United States)

Tsai, Wen-Chung; Yu, Tung-Yang; Lin, Li-Ping; Lin, Mioa-Sui; Tsai, Ting-Ta; Pang, Jong-Hwei S

2017-11-01

Platelet rich plasma (PRP) contains various cytokines and growth factors which may be beneficial to the healing process of injured muscle. The aim of this study was to investigate the effect and molecular mechanism of PRP on migration of skeletal muscle cells. Skeletal muscle cells intrinsic to Sprague-Dawley rats were treated with PRP. The cell migration was evaluated by transwell filter migration assay and electric cell-substrate impedance sensing. The spreading of cells was evaluated microscopically. The formation of filamentous actin (F-actin) cytoskeleton was assessed by immunofluorescence staining. The protein expressions of paxillin and focal adhesion kinase (FAK) were assessed by Western blot analysis. Transfection of paxillin small-interfering RNA (siRNAs) to muscle cells was performed to validate the role of paxillin in PRP-mediated promotion of cell migration. Dose-dependently PRP promotes migration of and spreading and muscle cells. Protein expressions of paxillin and FAK were up-regulated dose-dependently. F-actin formation was also enhanced by PRP treatment. Furthermore, the knockdown of paxillin expression impaired the effect of PRP to promote cell migration. It was concluded that PRP promoting migration of muscle cells is associated with up-regulation of proteins expression of paxillin and FAK as well as increasing F-actin formation. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2506-2512, 2017. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Neonatal maternal separation up-regulates protein signalling for cell survival in rat hypothalamus.

Science.gov (United States)

Irles, Claudine; Nava-Kopp, Alicia T; Morán, Julio; Zhang, Limei

2014-05-01

We have previously reported that in response to early life stress, such as maternal hyperthyroidism and maternal separation (MS), the rat hypothalamic vasopressinergic system becomes up-regulated, showing enlarged nuclear volume and cell number, with stress hyperresponsivity and high anxiety during adulthood. The detailed signaling pathways involving cell death/survival, modified by adverse experiences in this developmental window remains unknown. Here, we report the effects of MS on cellular density and time-dependent fluctuations of the expression of pro- and anti-apoptotic factors during the development of the hypothalamus. Neonatal male rats were exposed to 3 h-daily MS from postnatal days 2 to 15 (PND 2-15). Cellular density was assessed in the hypothalamus at PND 21 using methylene blue staining, and neuronal nuclear specific protein and glial fibrillary acidic protein immunostaining at PND 36. Expression of factors related to apoptosis and cell survival in the hypothalamus was examined at PND 1, 3, 6, 9, 12, 15, 20 and 43 by Western blot. Rats subjected to MS exhibited greater cell-density and increased neuronal density in all hypothalamic regions assessed. The time course of protein expression in the postnatal brain showed: (1) decreased expression of active caspase 3; (2) increased Bcl-2/Bax ratio; (3) increased activation of ERK1/2, Akt and inactivation of Bad; PND 15 and PND 20 were the most prominent time-points. These data indicate that MS can induce hypothalamic structural reorganization by promoting survival, suppressing cell death pathways, increasing cellular density which may alter the contribution of these modified regions to homeostasis.

Preparation, Modification, and Characterization of Alginate Hydrogel with Nano-/Microfibers: A New Perspective for Tissue Engineering

Directory of Open Access Journals (Sweden)

Bianca Palma Santana

2013-01-01

Full Text Available We aimed to develop an alginate hydrogel (AH modified with nano-/microfibers of titanium dioxide (nfTD and hydroxyapatite (nfHY and evaluated its biological and chemical properties. Nano-/microfibers of nfTD and nfHY were combined with AH, and its chemical properties were evaluated by FTIR spectroscopy, X-ray diffraction, energy dispersive X-Ray analysis, and the cytocompatibility by the WST-1 assay. The results demonstrate that the association of nfTD and nfHY nano-/microfibers to AH did not modified the chemical characteristics of the scaffold and that the association was not cytotoxic. In the first 3 h of culture with NIH/3T3 cells nfHY AH scaffolds showed a slight increase in cell viability when compared to AH alone or associated with nfTD. However, an increase in cell viability was observed in 24 h when nfTD was associated with AH scaffold. In conclusion our study demonstrates that the combination of nfHY and nfTD nano-/microfibers in AH scaffold maintains the chemical characteristics of alginate and that this association is cytocompatible. Additionally the combination of nfHY with AH favored cell viability in a short term, and the addition of nfTD increased cell viability in a long term.

Exploring continuous and integrated strategies for the up- and downstream processing of human mesenchymal stem cells.

Science.gov (United States)

Cunha, Bárbara; Aguiar, Tiago; Silva, Marta M; Silva, Ricardo J S; Sousa, Marcos F Q; Pineda, Earl; Peixoto, Cristina; Carrondo, Manuel J T; Serra, Margarida; Alves, Paula M

2015-11-10

The integration of up- and downstream unit operations can result in the elimination of hold steps, thus decreasing the footprint, and ultimately can create robust closed system operations. This type of design is desirable for the bioprocess of human mesenchymal stem cells (hMSC), where high numbers of pure cells, at low volumes, need to be delivered for therapy applications. This study reports a proof of concept of the integration of a continuous perfusion culture in bioreactors with a tangential flow filtration (TFF) system for the concentration and washing of hMSC. Moreover, we have also explored a continuous alternative for concentrating hMSC. Results show that expanding cells in a continuous perfusion operation mode provided a higher expansion ratio, and led to a shift in cells' metabolism. TFF operated either in continuous or discontinuous allowed to concentrate cells, with high cell recovery (>80%) and viability (>95%); furthermore, continuous TFF permitted to operate longer with higher cell concentrations. Continuous diafiltration led to higher protein clearance (98%) with lower cell death, when comparing to discontinuous diafiltration. Overall, an integrated process allowed for a shorter process time, recovering 70% of viable hMSC (>95%), with no changes in terms of morphology, immunophenotype, proliferation capacity and multipotent differentiation potential. Copyright © 2015 Elsevier B.V. All rights reserved.

Cathepsin B is up-regulated and mediates extracellular matrix degradation in trabecular meshwork cells following phagocytic challenge.

Directory of Open Access Journals (Sweden)

Kristine Porter

Full Text Available Cells in the trabecular meshwork (TM, a tissue responsible for draining aqueous humor out of the eye, are known to be highly phagocytic. Phagocytic activity in TM cells is thought to play an important role in outflow pathway physiology. However, the molecular mechanisms triggered by phagocytosis in TM cells are unknown. Here we investigated the effects of chronic phagocytic stress on lysosomal function using different phagocytic ligands (E. coli, carboxylated beads, collagen I-coated beads, and pigment. Lysotracker red co-localization and electron micrographs showed the maturation of E. coli- and collagen I-coated beads-containing phagosomes into phagolysosomes. Maturation of phagosomes into phagolysosomes was not observed with carboxylated beads or pigment particles. In addition, phagocytosis of E. coli and collagen I-coated beads led to increased lysosomal mass, and the specific up-regulation and activity of cathepsin B (CTSB. Higher levels of membrane-bound and secreted CTSB were also detected. Moreover, in vivo zymography showed the intralysosomal degradation of ECM components associated with active CTSB, as well as an overall increased gelatinolytic activity in phagocytically challenged TM cells. This increased gelatinolytic activity with phagocytosis was partially blocked with an intracellular CTSB inhibitor. Altogether, these results suggest a potential role of phagocytosis in outflow pathway tissue homeostasis through the up-regulation and/or proteolytic activation of extracellular matrix remodeling genes.

Design of a nitrogen-implanted titanium-based superelastic alloy with optimized properties for biomedical applications

International Nuclear Information System (INIS)

Gordin, D.M.; Busardo, D.; Cimpean, A.; Vasilescu, C.; Höche, D.; Drob, S.I.; Mitran, V.; Cornen, M.; Gloriant, T.

2013-01-01

In this study, a superelastic Ni-free Ti-based biomedical alloy was treated in surface by the implantation of nitrogen ions for the first time. The N-implanted surface was characterized by X-ray diffraction, X-ray photoelectron spectroscopy, and secondary ion mass spectroscopy, and the superficial mechanical properties were evaluated by nano-indentation and by ball-on-disk tribological tests. To investigate the biocompatibility, the corrosion resistance of the N-implanted Ti alloy was evaluated in simulated body fluids (SBF) complemented by in-vitro cytocompatibility tests on human fetal osteoblasts. After implantation, surface analysis methods revealed the formation of a titanium-based nitride on the substrate surface. Consequently, an increase in superficial hardness and a significant reduction of friction coefficient were observed compared to the non-implanted sample. Also, a better corrosion resistance and a significant decrease in ion release rates have been obtained. Cell culture experiments indicated that the cytocompatibility of the N-implanted Ti alloy was superior to that of the corresponding non-treated sample. Thus, this new functional N-implanted titanium-based superelastic alloy presents the optimized properties that are required for various medical devices: superelasticity, high superficial mechanical properties, high corrosion resistance and excellent cytocompatibility. - Highlights: • A superelastic Ni-free Ti-based biomedical alloy was treated in surface by implantation of nitrogen ions. • Much higher superficial hardness and wear resistance were obtained. • A clear enhancement of the corrosion resistance in SBF was observed. • In-vitro tests performed on human fetal osteoblasts indicated an excellent level of cytocompatibility

Design of a nitrogen-implanted titanium-based superelastic alloy with optimized properties for biomedical applications

Energy Technology Data Exchange (ETDEWEB)

Gordin, D.M. [INSA de Rennes, Laboratoire Chimie-Métallurgie, UMR CNRS 6226 Institut des Sciences Chimiques de Rennes, 20 avenue des Buttes de Coësmes, 35708 Rennes Cedex 7 (France); Busardo, D. [Quertech Ingénierie, 9 rue de la Girafe, 14000 Caen (France); Cimpean, A. [University of Bucharest, Department of Biochemistry and Molecular Biology, Spl. Independentei 91-95, 050095 Bucharest (Romania); Vasilescu, C. [Institute of Physical Chemistry «Ilie Murgulescu» of Romanian Academy, Spl. Independentei 202, 060021 Bucharest (Romania); Höche, D. [Institute of Materials Research, Helmholtz-Zentrum Geesthacht -Zentrum für Material- und Küstenforschung GmbH Max-Planck-Straße 1, D-21502 Geesthacht (Germany); Drob, S.I. [Institute of Physical Chemistry «Ilie Murgulescu» of Romanian Academy, Spl. Independentei 202, 060021 Bucharest (Romania); Mitran, V. [University of Bucharest, Department of Biochemistry and Molecular Biology, Spl. Independentei 91-95, 050095 Bucharest (Romania); Cornen, M. [INSA de Rennes, Laboratoire Chimie-Métallurgie, UMR CNRS 6226 Institut des Sciences Chimiques de Rennes, 20 avenue des Buttes de Coësmes, 35708 Rennes Cedex 7 (France); Gloriant, T., E-mail: Thierry.Gloriant@insa-rennes.fr [INSA de Rennes, Laboratoire Chimie-Métallurgie, UMR CNRS 6226 Institut des Sciences Chimiques de Rennes, 20 avenue des Buttes de Coësmes, 35708 Rennes Cedex 7 (France)

2013-10-15

In this study, a superelastic Ni-free Ti-based biomedical alloy was treated in surface by the implantation of nitrogen ions for the first time. The N-implanted surface was characterized by X-ray diffraction, X-ray photoelectron spectroscopy, and secondary ion mass spectroscopy, and the superficial mechanical properties were evaluated by nano-indentation and by ball-on-disk tribological tests. To investigate the biocompatibility, the corrosion resistance of the N-implanted Ti alloy was evaluated in simulated body fluids (SBF) complemented by in-vitro cytocompatibility tests on human fetal osteoblasts. After implantation, surface analysis methods revealed the formation of a titanium-based nitride on the substrate surface. Consequently, an increase in superficial hardness and a significant reduction of friction coefficient were observed compared to the non-implanted sample. Also, a better corrosion resistance and a significant decrease in ion release rates have been obtained. Cell culture experiments indicated that the cytocompatibility of the N-implanted Ti alloy was superior to that of the corresponding non-treated sample. Thus, this new functional N-implanted titanium-based superelastic alloy presents the optimized properties that are required for various medical devices: superelasticity, high superficial mechanical properties, high corrosion resistance and excellent cytocompatibility. - Highlights: • A superelastic Ni-free Ti-based biomedical alloy was treated in surface by implantation of nitrogen ions. • Much higher superficial hardness and wear resistance were obtained. • A clear enhancement of the corrosion resistance in SBF was observed. • In-vitro tests performed on human fetal osteoblasts indicated an excellent level of cytocompatibility.

Sol-gel synthesis and in vitro bioactivity of copper and zinc-doped silicate bioactive glasses and glass-ceramics.

Science.gov (United States)

Bejarano, Julian; Caviedes, Pablo; Palza, Humberto

2015-03-11

Metal doping of bioactive glasses based on ternary 60SiO2-36CaO-4P2O5 (58S) and quaternary 60SiO2-25CaO-11Na2O-4P2O5 (NaBG) mol% compositions synthesized using a sol-gel process was analyzed. In particular, the effect of incorporating 1, 5 and 10 mol% of CuO and ZnO (replacing equivalent quantities of CaO) on the texture, in vitro bioactivity, and cytocompatibility of these materials was evaluated. Our results showed that the addition of metal ions can modulate the textural property of the matrix and its crystal structure. Regarding the bioactivity, after soaking in simulated body fluid (SBF) undoped 58S and NaBG glasses developed an apatite surface layer that was reduced in the doped glasses depending on the type of metal and its concentration with Zn displaying the largest inhibitions. Both the ion release from samples and the ion adsorption from the medium depended on the type of matrix with 58S glasses showing the highest values. Pure NaBG glass was more cytocompatible to osteoblast-like cells (SaOS-2) than pure 58S glass as tested by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. The incorporation of metal ions decreased the cytocompatibility of the glasses depending on their concentration and on the glass matrix doped. Our results show that by changing the glass composition and by adding Cu or Zn, bioactive materials with different textures, bioactivity and cytocompatibility can be synthesized.

Computational fluid dynamics analysis of an innovative start-up method of high temperature fuel cells using dynamic 3d model

Directory of Open Access Journals (Sweden)

Kupecki Jakub

2017-03-01

Full Text Available The article presents a numerical analysis of an innovative method for starting systems based on high temperature fuel cells. The possibility of preheating the fuel cell stacks from the cold state to the nominal working conditions encounters several limitations related to heat transfer and stability of materials. The lack of rapid and safe start-up methods limits the proliferation of MCFCs and SOFCs. For that reason, an innovative method was developed and verified using the numerical analysis presented in the paper. A dynamic 3D model was developed that enables thermo-fluidic investigations and determination of measures for shortening the preheating time of the high temperature fuel cell stacks. The model was implemented in ANSYS Fluent computational fluid dynamic (CFD software and was used for verification of the proposed start-up method. The SOFC was chosen as a reference fuel cell technology for the study. Results obtained from the study are presented and discussed.

Inferior clinical outcome of the CD4+ cell count-guided antiretroviral treatment interruption strategy in the SMART study: role of CD4+ Cell counts and HIV RNA levels during follow-up

DEFF Research Database (Denmark)

Lundgren, Jens; Babiker, Abdel; El-Sadr, Wafaa

2008-01-01

BACKGROUND AND METHODS: The SMART study compared 2 strategies for using antiretroviral therapy-drug conservation (DC) and viral suppression (VS)-in 5,472 human immunodeficiency virus (HIV)-infected patients with CD4+ cell counts >350 cells/microL. Rates and predictors of opportunistic disease...... or death (OD/death) and the relative risk (RR) in DC versus VS groups according to the latest CD4+ cell count and HIV RNA level are reported. RESULTS: During a mean of 16 months of follow-up, DC patients spent more time with a latest CD4+ cell count ...%) and with a latest HIV RNA level >400 copies/mL (71% vs. 28%) and had a higher rate of OD/death (3.4 vs. 1.3/100 person-years) than VS patients. For periods of follow- up with a CD4+ cell count

Allometric scaling of microbial fuel cells and stacks: The lifeform case for scale-up

Science.gov (United States)

Greenman, John; Ieropoulos, Ioannis A.

2017-07-01

This case study reports for the first time on the comparison between allometric scaling of lifeforms and scale-up of microbial fuel cell entities; enlarging individual units in volume, footprint and electrode surface area but also multiplying a static size/footprint and electrode surface area to scale-up by stacking. A study published in 2010 by DeLong et al. showed for the first time that Kleiber's law does not apply uniformly to all lifeforms, and that in fact growth rate for prokaryotes is superlinear, for protists is linear and for metazoa is sublinear. The current study, which is utilising data from previous experiments, is showing for the first time that for individual MFC units, which are enlarged, growth rate/power is sublinear, whereas for stacks this is superlinear.

In vitro investigation of a tissue-engineered cell-tendon complex mimicking the transitional architecture at the ligament-bone interface.

Science.gov (United States)

Wang, Zhibing; Zhang, Yuan; Zhu, Jie; Dong, Shiwu; Jiang, Tao; Zhou, Yue; Zhang, Xia

2015-03-01

Restoration of the transitional ligament-bone interface is critical for graft-bone integration. We postulated that an allogenic scaffold mimicking the fibrogenic, chondrogenic, and osteogenic transition gradients could physiologically promote ligament-bone incorporation. The aim of this study was to construct and characterize a composite tendon scaffold with a continuous and heterogeneous transition region mimicking a native ligament insertion site. Genetically modified heterogeneous cell populations were seeded within specific regions of decellularized rabbit Achilles tendons to fabricate a stratified scaffold containing three biofunctional regions supporting fibrogenesis, chondrogenesis, and osteogenesis. The observed morphology, architecture, cytocompatibility, and biomechanics of the scaffolds demonstrated their improved bio-physico-chemical properties. The formation of the transitional regions was augmented via enhanced delivery of two transcription factors, sex determining region Y-box 9 and runt-related transcription factor 2, which also triggered early up-regulated expression of cartilage- and bone-relevant markers, according to quantitative PCR and immunoblot analyses. Gradient tissue-specific matrix formation was also confirmed within the predesignated regions via histological staining and immunofluorescence assays. These results suggest that a transitional interface could be replicated on an engineered tendon through stratified tissue integration. The scaffold offers the advantages of a multitissue transition involving controlled cellular interactions and matrix heterogeneity, which can be applied for the regeneration of the ligament-bone interface. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Maggot debridement therapy promotes diabetic foot wound healing by up-regulating endothelial cell activity.

Science.gov (United States)

Sun, Xinjuan; Chen, Jin'an; Zhang, Jie; Wang, Wei; Sun, Jinshan; Wang, Aiping

2016-03-01

To determine the role of maggot debridement therapy (MDT) on diabetic foot wound healing, we compared growth related factors in wounds before and after treatment. Furthermore, we utilized human umbilical vein endothelial cells (HUVECs) to explore responses to maggot excretions/secretions on markers of angiogenesis and proliferation. The results showed that there was neo-granulation and angiogenesis in diabetic foot wounds after MDT. Moreover, significant elevation in CD34 and CD68 levels was also observed in treated wounds. In vitro, ES increased HUVEC proliferation, improved tube formation, and increased expression of vascular endothelial growth factor receptor 2 in a dose dependent manner. These results demonstrate that MDT and maggot ES can promote diabetic foot wound healing by up-regulating endothelial cell activity. Copyright © 2016. Published by Elsevier Inc.

Off-take and slug transition at T-junction of vertical-up branch in the horizontal pipe

International Nuclear Information System (INIS)

Moon, Young Min; No, Hee Cheon

2003-01-01

The off-take and the slug transition on air-water interface are experimentally investigated at the T-junction of the horizontal pipe with a vertical upward branch to simulate the loss-of-residual-heat-removal during a mid-loop operation in the Korea standard nuclear power plant. Scaling analysis is performed to scale down the experimental facility to the reference nuclear power plant. Two different diameters of branch pipes are used to verify the scaling laws and their scale effects. Air is used as working gaseous fluid and no water flow exists. Off-take behavior on horizontal stratified and slug flows is visually observed in the horizontal pipe. The experimental data are divided into three categories; onset of liquid entrainment at T-junctions, onset of slug transition in the horizontal pipe, and discharge quality in the branch pipe. It is found out that the scale effect of the branch diameter on the onset of liquid entrainment is small and the existing correlations for it are applicable. Also, the onset of slug transition shows a discrepancy with Taitel-Dukler's correlation and has a strong influence on the discharge quality. New correlations for discharge quality are developed considering the critical dependency of the onset of slugging. (author)

Rapid biomimetic mineralization of collagen fibrils and combining with human umbilical cord mesenchymal stem cells for bone defects healing

Energy Technology Data Exchange (ETDEWEB)

Ye, Bihua; Luo, Xueshi; Li, Zhiwen [Department of Material Science and Engineering, Engineering Research Center of Artificial Organs and Materials, Jinan University, Guangzhou 510632 (China); Zhuang, Caiping [Department of Anesthesiology, Huizhou Central People' s Hospital, Huizhou 516001 (China); Li, Lihua, E-mail: tlihuali@jnu.edu.cn [Department of Material Science and Engineering, Engineering Research Center of Artificial Organs and Materials, Jinan University, Guangzhou 510632 (China); Lu, Lu; Ding, Shan; Tian, Jinhuan [Department of Material Science and Engineering, Engineering Research Center of Artificial Organs and Materials, Jinan University, Guangzhou 510632 (China); Zhou, Changren, E-mail: tcrz9@jnu.edu.cn [Department of Material Science and Engineering, Engineering Research Center of Artificial Organs and Materials, Jinan University, Guangzhou 510632 (China)

2016-11-01

Collagen biomineralization is regulated by complicated interactions between the collagen matrix and non-collagenous extracellular proteins. Here, the use of sodium tripolyphosphate to simulate the templating functional motif of the C-terminal fragment of non-collagenous proteins is reported, and a low molecular weight polyacrylic acid served as a sequestration agent to stabilize amorphous calcium phosphate into nanoprecursors. Self-assembled collagen fibrils served as a fixed template for achieving rapid biomimetic mineralization in vitro. Results demonstrated that, during the mineralization process, intrafibrillar and extrafibrillar hydroxyapatite mineral with collagen fibrils formed and did so via bottom-up nanoparticle assembly based on the non-classical crystallization approach in the presence of these dual biomimetic functional analogues. In vitro human umbilical cord mesenchymal stem cell (hUCMSC) culture found that the mineralized scaffolds have a better cytocompatibility in terms of cell viability, adhesion, proliferation, and differentiation into osteoblasts. A rabbit femoral condyle defect model was established to confirm the ability of the n-HA/collagen scaffolds to facilitate bone regeneration and repair. The images of gross anatomy, MRI, CT and histomorphology taken 6 and 12 weeks after surgery showed that the biomimetic mineralized collagen scaffolds with hUCMSCs can promote the healing speed of bone defects in vivo, and both of the scaffolds groups performing better than the bone defect control group. As new bone tissue formed, the scaffolds degraded and were gradually absorbed. All these results demonstrated that both of the scaffolds and cells have better histocompatibility. - Highlights: • A rapid and facile biomimetic mineralization approach is proposed. • Intrafibrillar and extrafibrillar mineralization of collagen fibrils was achieved. • HA/COL scaffolds promote hUCMSCs adhesion, proliferation, and differentiation. • Feasibility of h

Rapid biomimetic mineralization of collagen fibrils and combining with human umbilical cord mesenchymal stem cells for bone defects healing

International Nuclear Information System (INIS)

Ye, Bihua; Luo, Xueshi; Li, Zhiwen; Zhuang, Caiping; Li, Lihua; Lu, Lu; Ding, Shan; Tian, Jinhuan; Zhou, Changren

2016-01-01

Collagen biomineralization is regulated by complicated interactions between the collagen matrix and non-collagenous extracellular proteins. Here, the use of sodium tripolyphosphate to simulate the templating functional motif of the C-terminal fragment of non-collagenous proteins is reported, and a low molecular weight polyacrylic acid served as a sequestration agent to stabilize amorphous calcium phosphate into nanoprecursors. Self-assembled collagen fibrils served as a fixed template for achieving rapid biomimetic mineralization in vitro. Results demonstrated that, during the mineralization process, intrafibrillar and extrafibrillar hydroxyapatite mineral with collagen fibrils formed and did so via bottom-up nanoparticle assembly based on the non-classical crystallization approach in the presence of these dual biomimetic functional analogues. In vitro human umbilical cord mesenchymal stem cell (hUCMSC) culture found that the mineralized scaffolds have a better cytocompatibility in terms of cell viability, adhesion, proliferation, and differentiation into osteoblasts. A rabbit femoral condyle defect model was established to confirm the ability of the n-HA/collagen scaffolds to facilitate bone regeneration and repair. The images of gross anatomy, MRI, CT and histomorphology taken 6 and 12 weeks after surgery showed that the biomimetic mineralized collagen scaffolds with hUCMSCs can promote the healing speed of bone defects in vivo, and both of the scaffolds groups performing better than the bone defect control group. As new bone tissue formed, the scaffolds degraded and were gradually absorbed. All these results demonstrated that both of the scaffolds and cells have better histocompatibility. - Highlights: • A rapid and facile biomimetic mineralization approach is proposed. • Intrafibrillar and extrafibrillar mineralization of collagen fibrils was achieved. • HA/COL scaffolds promote hUCMSCs adhesion, proliferation, and differentiation. • Feasibility of h

Up-regulated microRNA-143 in cancer stem cells differentiation promotes prostate cancer cells metastasis by modulating FNDC3B expression

International Nuclear Information System (INIS)

Fan, Xinlan; Chen, Xu; Deng, Weixi; Zhong, Guangzheng; Cai, Qingqing; Lin, Tianxin

2013-01-01

Metastatic prostate cancer is a leading cause of cancer-related death in men. Cancer stem cells (CSCs) are involved in tumor progression and metastasis, including in prostate cancer. There is an obvious and urgent need for effective cancer stem cells specific therapies in metastatic prostate cancer. MicroRNAs (miRNAs) are an important class of pervasive genes that are involved in a variety of biological functions, especially in cancer. The goal of this study was to identify miRNAs involved in prostate cancer metastasis and cancer stem cells. A microarray and qRT-PCR were performed to investigate the miRNA expression profiles in PC-3 sphere cells and adherent cells. A transwell assay was used to evaluate the migration of PC-3 sphere cells and adherent cells. MiR-143 was silenced with antisense oligonucleotides in PC-3, PC-3-M and LNCaP cells. The role of miR-143 in prostate cancer metastasis was measured by wound-healing and transwell assays in vitro and bioluminescence imaging in vivo. Bioinformatics and luciferase report assays were used to identify the target of miR-143. The expression of miR-143 and the migration capability were reduced in PC-3 sphere cells and progressively increased during sphere re-adherent culture. Moreover, the down-regulation of miR-143 suppressed prostate cancer cells migration and invasion in vitro and systemically inhibited metastasis in vivo. Fibronectin type III domain containing 3B (FNDC3B), which regulates cell motility, was identified as a target of miR-143. The inhibition of miR-143 increased the expression of FNDC3B protein but not FNDC3B mRNA in vitro and vivo. These data demonstrate for the first time that miR-143 was up-regulated during the differentiation of prostate cancer stem cells and promoted prostate cancer metastasis by repressing FNDC3B expression. This sheds a new insight into the post-transcriptional regulation of cancer stem cells differentiation by miRNAs, a potential approach for the treatment of prostate cancer

A COMPUTATIONAL FLUID DYNAMICS ANALYSIS OF AIR FLOW THROUGH A TELECOM BACK-UP UNIT POWERED BY AN AIR-COOLED PROTON EXCHANGE MEMBRANE FUEL CELL

DEFF Research Database (Denmark)

Gao, Xin; Berning, Torsten; Kær, Søren Knudsen

2016-01-01

Proton exchange membrane fuel cells (PEMFC’s) are currently being commercialized for various applications ranging from automotive to stationary such as powering telecom back-up units. In PEMFC’s, oxygen from air is internally combined with hydrogen to form water and produce electricity and heat....... This product heat has to be effectively removed from the fuel cell, and while automotive fuel cells are usually liquid-cooled using a secondary coolant loop similar to the internal combustion engines, stationary fuel cell systems as they are used for telecom back-up applications often rely on excessive air fed...... to the fuel cell cathode to remove the heat. Thereby, the fuel cell system is much simpler and cheaper while the fuel cell performance is substantially lower compared to automotive fuel cells. This work presents a computational fluid dynamics analysis on the heat management of an air-cooled fuel cell powered...