Modelling in Action. Scaffolding High School Students to Higher Levels of Autonomy: The School's Elevator and the Inverse Problem

Science.gov (United States)

Marmolejo Rivas, Eugenia

2017-01-01

In this paper, we focus our discussion on the strategy we follow to scaffold high school students to successfully build models of a real-life system. Our aim is for students to gradually achieve a higher level of autonomy and to use and further develop their mathematical knowledge. We present work students did when we asked them to build a model…

Mindfulness in higher education: awareness and attention in university students increase during and after participation in a mindfulness curriculum course

NARCIS (Netherlands)

de Bruin, E.I.; Meppelink, R.; Bögels, S.M.

2015-01-01

This study assessed the effects of a mindfulness course in the curriculum of international students (n = 104) from 16 different countries at the University of Amsterdam. The curriculum consisted of seven weekly lectures, as well as studying scientific articles on mindfulness research and gaining

When Traits Match States: Examining the Associations between Self-Report Trait and State Mindfulness following a State Mindfulness Induction.

Science.gov (United States)

Bravo, Adrian J; Pearson, Matthew R; Wilson, Adam D; Witkiewitz, Katie

2018-02-01

Previous research has found inconsistent relationships between trait mindfulness and state mindfulness. To extend previous research, we sought to examine the unique associations between self-report trait mindfulness and state mindfulness by levels of meditation experience (meditation-naïve vs. meditation-experienced) and by mindfulness induction (experimentally induced mindful state vs. control group). We recruited 299 college students (93 with previous mindfulness meditation experience) to participate in an experiment that involved the assessment of five facets of trait mindfulness (among other constructs), followed by a mindfulness induction (vs. control), followed by the assessment of state mindfulness of body and mind. Correlational analyses revealed limited associations between trait mindfulness facets and facets of state mindfulness, and demonstrated that a brief mindfulness exercise focused on bodily sensations and the breath elicited higher state mindfulness of body but not state mindfulness of mind. We found significant interactions such that individuals with previous meditation experience and higher scores on the observing facet of trait mindfulness had the highest levels of state mindfulness of body and mind. Among individuals with meditation experience, the strengths of the associations between observing trait mindfulness and the state mindfulness facets increased with frequency of meditation practice. Some other interactions ran counter to expectations. Overall, the relatively weak associations between trait and state mindfulness demonstrates the need to improve our operationalizations of mindfulness, advance our understanding of how to best cultivate mindfulness, and reappraise the ways in which mindfulness can manifest as a state and as a trait.

Higher mind-brain development in successful leaders: testing a unified theory of performance.

Science.gov (United States)

Harung, Harald S; Travis, Frederick

2012-05-01

This study explored mind-brain characteristics of successful leaders as reflected in scores on the Brain Integration Scale, Gibbs's Socio-moral Reasoning questionnaire, and an inventory of peak experiences. These variables, which in previous studies distinguished world-class athletes and professional classical musicians from average-performing controls, were recorded in 20 Norwegian top-level managers and in 20 low-level managers-matched for age, gender, education, and type of organization (private or public). Top-level managers were characterized by higher Brain Integration Scale scores, higher levels of moral reasoning, and more frequent peak experiences. These multilevel measures could be useful tools in selection and recruiting of potential managers and in assessing leadership education and development programs. Future longitudinal research could further investigate the relationship between leadership success and these and other multilevel variables.

Poly (hydroxybutyrate co hydroxyvalerate Nanofibrous Scaffold Containing HydroxyapatiteBredigite Nanoparticles: Characterization and Biological Evaluation

Directory of Open Access Journals (Sweden)

M. Kouhi

2017-11-01

Full Text Available In this work, poly (hydroxybutyrate co hydroxyvalerate (PHBV composite nanofibrous scaffold containing hydroxyapatite/bredigite (HABR nanoparticles was fabricated through electrospining method. The morphology of prepared  nanofibers and the state of the nanoparticles dispersion in nanofiber matrix were investigated using scanning and transmission electron microscopy, respectively. Evaluation of the mechanical properties of the nanofibrous scaffolds revealed that there is a limit to the nanoparticle concentration at which nanoparticles can improve the mechanical properties of the nanofibrous scaffolds. According to the results, PHBV/HABR nanofibers showed higher wettability compared to PHBV nanofibers. In vitro cell culture assay was done using human fetal osteoblast cells on nanofibrous scaffold. MTS assay revealed that cell proliferation on the composite nanofibrous scaffold was significantly higher than those on the pure scaffold after 10 and 15 days. Scanning electron microscopy- Energy dispersive X-ray spectroscopy and CMFDA colorimeter assay analysis showed that the cells on the PHBV/HABR scaffolds acquired higher mineral deposition than the cells on the pure PHBV and control sample scaffold. Based on the results we concluded that PHBV/HABR nanofibers scaffold with higher wettability, improved mechanical properties and cell behavior hold great potential in bone regeneration applications.

Novel biodegradable porous scaffold applied to skin regeneration.

Science.gov (United States)

Wang, Hui-Min; Chou, Yi-Ting; Wen, Zhi-Hong; Wang, Chau-Zen; Wang, Zhao-Ren; Chen, Chun-Hong; Ho, Mei-Ling

2013-01-01

Skin wound healing is an important lifesaving issue for massive lesions. A novel porous scaffold with collagen, hyaluronic acid and gelatin was developed for skin wound repair. The swelling ratio of this developed scaffold was assayed by water absorption capacity and showed a value of over 20 g water/g dried scaffold. The scaffold was then degraded in time- and dose-dependent manners by three enzymes: lysozyme, hyaluronidase and collagenase I. The average pore diameter of the scaffold was 132.5±8.4 µm measured from SEM images. With human skin cells growing for 7 days, the SEM images showed surface fractures on the scaffold due to enzymatic digestion, indicating the biodegradable properties of this scaffold. To simulate skin distribution, the human epidermal keratinocytes, melanocytes and dermal fibroblasts were seeded on the porous scaffold and the cross-section immunofluorescent staining demonstrated normal human skin layer distributions. The collagen amount was also quantified after skin cells seeding and presented an amount 50% higher than those seeded on culture wells. The in vivo histological results showed that the scaffold ameliorated wound healing, including decreasing neutrophil infiltrates and thickening newly generated skin compared to the group without treatments.

Novel biodegradable porous scaffold applied to skin regeneration.

Directory of Open Access Journals (Sweden)

Hui-Min Wang

Full Text Available Skin wound healing is an important lifesaving issue for massive lesions. A novel porous scaffold with collagen, hyaluronic acid and gelatin was developed for skin wound repair. The swelling ratio of this developed scaffold was assayed by water absorption capacity and showed a value of over 20 g water/g dried scaffold. The scaffold was then degraded in time- and dose-dependent manners by three enzymes: lysozyme, hyaluronidase and collagenase I. The average pore diameter of the scaffold was 132.5±8.4 µm measured from SEM images. With human skin cells growing for 7 days, the SEM images showed surface fractures on the scaffold due to enzymatic digestion, indicating the biodegradable properties of this scaffold. To simulate skin distribution, the human epidermal keratinocytes, melanocytes and dermal fibroblasts were seeded on the porous scaffold and the cross-section immunofluorescent staining demonstrated normal human skin layer distributions. The collagen amount was also quantified after skin cells seeding and presented an amount 50% higher than those seeded on culture wells. The in vivo histological results showed that the scaffold ameliorated wound healing, including decreasing neutrophil infiltrates and thickening newly generated skin compared to the group without treatments.

Incorporating Mind Maps into Teaching and Learning in Higher Education: My Experience as an International University Lecturer

Science.gov (United States)

Guo, Xin

2014-01-01

This article seeks to share the author's teaching experience as an international lecturer in a UK university and in particular promote the use of Mind Maps (MM) in teaching and learning in higher education. The audience to whom the article could be beneficial is university lecturers who either are in their early teaching career or face challenges…

Enhanced chondrogenesis of human nasal septum derived progenitors on nanofibrous scaffolds

Energy Technology Data Exchange (ETDEWEB)

Shafiee, Abbas [Department of Tissue Engineering, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Stem Cell biology and Tissue Engineering Departments, Stem Cell Technology Research Center, Tehran (Iran, Islamic Republic of); Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Brisbane, QLD (Australia); Seyedjafari, Ehsan [Department of Biotechnology, College of Science, University of Tehran, Tehran (Iran, Islamic Republic of); Sadat Taherzadeh, Elham [Stem Cell biology and Tissue Engineering Departments, Stem Cell Technology Research Center, Tehran (Iran, Islamic Republic of); Dinarvand, Peyman [Stem Cell biology and Tissue Engineering Departments, Stem Cell Technology Research Center, Tehran (Iran, Islamic Republic of); The Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, Saint Louis, MO (United States); Soleimani, Masoud [Hematology Department, Faculty of Medical Science, Tarbiat Modares University, Tehran (Iran, Islamic Republic of); Ai, Jafar, E-mail: jafar_ai@tums.ac.ir [Department of Tissue Engineering, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Brain and Spinal Injury Research Center, Imam Hospital, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of)

2014-07-01

Topographical cues can be exploited to regulate stem cell attachment, proliferation, differentiation and function in vitro and in vivo. In this study, we aimed to investigate the influence of different nanofibrous topographies on the chondrogenic differentiation potential of nasal septum derived progenitors (NSP) in vitro. Aligned and randomly oriented Ploy (L-lactide) (PLLA)/Polycaprolactone (PCL) hybrid scaffolds were fabricated via electrospinning. First, scaffolds were fully characterized, and then NSP were seeded on them to study their capacity to support stem cell attachment, proliferation and chondrogenic differentiation. Compared to randomly oriented nanofibers, aligned scaffolds showed a high degree of nanofiber alignment with much better tensile strength properties. Both scaffolds supported NSP adhesion, proliferation and chondrogenic differentiation. Despite the higher rate of cell proliferation on random scaffolds, a better chondrogenic differentiation was observed on aligned nanofibers as deduced from higher expression of chondrogenic markers such as collagen type II and aggrecan on aligned scaffolds. These findings demonstrate that electrospun constructs maintain NSP proliferation and differentiation, and that the aligned nanofibrous scaffolds can significantly enhance chondrogenic differentiation of nasal septum derived progenitors. - Highlights: • Electrospun nanofiber scaffolds with different topographies were fabricated. • Aligned nanofiber scaffolds had better tensile strength properties. • Nasal septum derived progenitors were cultured on nanofibrous scaffolds. • Both topographies support proliferation and chondrogenic differentiation. • Better chondrogenic differentiation was observed on aligned nanofibers.

Enhanced chondrogenesis of human nasal septum derived progenitors on nanofibrous scaffolds

International Nuclear Information System (INIS)

Shafiee, Abbas; Seyedjafari, Ehsan; Sadat Taherzadeh, Elham; Dinarvand, Peyman; Soleimani, Masoud; Ai, Jafar

2014-01-01

Topographical cues can be exploited to regulate stem cell attachment, proliferation, differentiation and function in vitro and in vivo. In this study, we aimed to investigate the influence of different nanofibrous topographies on the chondrogenic differentiation potential of nasal septum derived progenitors (NSP) in vitro. Aligned and randomly oriented Ploy (L-lactide) (PLLA)/Polycaprolactone (PCL) hybrid scaffolds were fabricated via electrospinning. First, scaffolds were fully characterized, and then NSP were seeded on them to study their capacity to support stem cell attachment, proliferation and chondrogenic differentiation. Compared to randomly oriented nanofibers, aligned scaffolds showed a high degree of nanofiber alignment with much better tensile strength properties. Both scaffolds supported NSP adhesion, proliferation and chondrogenic differentiation. Despite the higher rate of cell proliferation on random scaffolds, a better chondrogenic differentiation was observed on aligned nanofibers as deduced from higher expression of chondrogenic markers such as collagen type II and aggrecan on aligned scaffolds. These findings demonstrate that electrospun constructs maintain NSP proliferation and differentiation, and that the aligned nanofibrous scaffolds can significantly enhance chondrogenic differentiation of nasal septum derived progenitors. - Highlights: • Electrospun nanofiber scaffolds with different topographies were fabricated. • Aligned nanofiber scaffolds had better tensile strength properties. • Nasal septum derived progenitors were cultured on nanofibrous scaffolds. • Both topographies support proliferation and chondrogenic differentiation. • Better chondrogenic differentiation was observed on aligned nanofibers

Gelatin Scaffolds with Controlled Pore Structure and Mechanical Property for Cartilage Tissue Engineering.

Science.gov (United States)

Chen, Shangwu; Zhang, Qin; Nakamoto, Tomoko; Kawazoe, Naoki; Chen, Guoping

2016-03-01

Engineering of cartilage tissue in vitro using porous scaffolds and chondrocytes provides a promising approach for cartilage repair. However, nonuniform cell distribution and heterogeneous tissue formation together with weak mechanical property of in vitro engineered cartilage limit their clinical application. In this study, gelatin porous scaffolds with homogeneous and open pores were prepared using ice particulates and freeze-drying. The scaffolds were used to culture bovine articular chondrocytes to engineer cartilage tissue in vitro. The pore structure and mechanical property of gelatin scaffolds could be well controlled by using different ratios of ice particulates to gelatin solution and different concentrations of gelatin. Gelatin scaffolds prepared from ≥70% ice particulates enabled homogeneous seeding of bovine articular chondrocytes throughout the scaffolds and formation of homogeneous cartilage extracellular matrix. While soft scaffolds underwent cellular contraction, stiff scaffolds resisted cellular contraction and had significantly higher cell proliferation and synthesis of sulfated glycosaminoglycan. Compared with the gelatin scaffolds prepared without ice particulates, the gelatin scaffolds prepared with ice particulates facilitated formation of homogeneous cartilage tissue with significantly higher compressive modulus. The gelatin scaffolds with highly open pore structure and good mechanical property can be used to improve in vitro tissue-engineered cartilage.

Agent-based models for higher-order theory of mind

NARCIS (Netherlands)

de Weerd, Harmen; Verbrugge, Rineke; Verheij, Bart; Kamiński, Bogumił; Koloch, Grzegorz

2014-01-01

Agent-based models are a powerful tool for explaining the emergence of social phenomena in a society. In such models, individual agents typically have little cognitive ability. In this paper, we model agents with the cognitive ability to make use of theory of mind. People use this ability to reason

Development of porous Ti6Al4V/chitosan sponge composite scaffold for orthopedic applications

International Nuclear Information System (INIS)

Guo, Miao; Li, Xiang

2016-01-01

A novel composite scaffold consisting of porous Ti6Al4V part filled with chitosan sponge was fabricated using a combination of electron beam melting and freeze-drying. The mechanical properties of porous Ti6Al4V part were examined via compressive test. The ultimate compressive strength was 85.35 ± 8.68 MPa and the compressive modulus was 2.26 ± 0.42 GPa. The microstructure of composite scaffold was characterized using scanning electron microscopy. The chitosan sponge filled in Ti6Al4V part exhibited highly porous and well-interconnected micro-pore architecture. The osteoblastic cells were seeded on scaffolds to test their seeding efficiency and biocompatibility. Significantly higher cell seeding efficiency was found on composite scaffold. The biological response of osteoblasts on composite scaffolds was superior in terms of improved cell attachment, higher proliferation, and well-spread morphology in relation to porous Ti6Al4V part. These results suggest that the Ti6Al4V/chitosan composite scaffold is potentially useful as a biomedical scaffold for orthopedic applications. - Highlights: • A novel composite scaffold with sufficient mechanical properties and favorable cell affinity environment was developed. • Significantly higher cell seeding efficiency was found on composite scaffold. • The osteoblasts on composite scaffolds showed well-spread morphology, improved cell attachment and higher proliferation.

Cell-derived matrix coatings for polymeric scaffolds.

Science.gov (United States)

Decaris, Martin L; Binder, Bernard Y; Soicher, Matthew A; Bhat, Archana; Leach, J Kent

2012-10-01

Cells in culture deposit a complex extracellular matrix that remains intact following decellularization and possesses the capacity to modulate cell phenotype. The direct application of such decellularized matrices (DMs) to 3D substrates is problematic, as transport issues influence the homogeneous deposition, decellularization, and modification of DM surface coatings. In an attempt to address this shortcoming, we hypothesized that DMs deposited by human mesenchymal stem cells (MSCs) could be transferred to the surface of polymeric scaffolds while maintaining their capacity to direct cell fate. The ability of the transferred DM (tDM)-coated scaffolds to enhance the osteogenic differentiation of undifferentiated and osteogenically induced MSCs under osteogenic conditions in vitro was confirmed. tDM-coated scaffolds increased MSC expression of osteogenic marker genes (BGLAP, IBSP) and intracellular alkaline phosphatase production. In addition, undifferentiated MSCs deposited significantly more calcium when seeded onto tDM-coated scaffolds compared with control scaffolds. MSC-seeded tDM-coated scaffolds subcutaneously implanted in nude rats displayed significantly higher blood vessel density after 2 weeks compared with cells on uncoated scaffolds, but we did not observe significant differences in mineral deposition after 8 weeks. These data demonstrate that DM-coatings produced in 2D culture can be successfully transferred to 3D substrates and retain their capacity to modulate cell phenotype.

A Ternary Nanofibrous Scaffold Potential for Central Nerve System Tissue Engineering.

Science.gov (United States)

Saadatkish, Niloufar; Nouri Khorasani, Saied; Morshed, Mohammad; Allafchian, Ali-Reza; Beigi, Mohammad-Hossein; Masoudi Rad, Maryam; Nasr-Esfahani, Mohammad Hossein; Esmaeely Neisiany, Rasoul

2018-04-10

In the present research, a ternary Polycaprolactone (PCL)/gelatin/fibrinogen nanofibrous scaffold for tissue engineering application was developed. Through this combination, PCL improved the scaffold mechanical properties; meanwhile, gelatin and fibrinogen provided more hydrophilicity and cell proliferation. Three types of nanofibrous scaffolds containing different fibrinogen contents were prepared and characterized. Morphological study of the nanofibers showed that the prepared nanofibers were smooth, uniform without any formation of beads with a significant reduction in nanofiber diameter after incorporation of fibrinogen. The chemical characterization of the scaffolds confirmed that no chemical reaction occurred between the scaffold components. The tensile test results of the scaffolds showed that increasing in fibrinogen content led to a decrease in mechanical properties. Furthermore, Adipose-derived stem cells (ADSCs) were employed to evaluate cell-scaffold interaction. Cell culture results indicated that higher cell proliferation occurred for the higher amount of fibrinogen. Statistical analysis was also carried out to evaluate the significant difference for the obtained results of water droplet contact angle and cell culture. Therefore, the results confirmed that PCL/Gel/Fibrinogen scaffold has a good potential for tissue engineering applications including Central Nerve System (CNS) tissue engineering. This article is protected by copyright. All rights reserved. © 2018 Wiley Periodicals, Inc.

Scaffolding Singaporean Students to Write Vividly in the Chinese ‘Mother Tongue’, Mandarin

Directory of Open Access Journals (Sweden)

Tzemin Chung

2014-02-01

Full Text Available This paper details results from a three-year study investigating how to help students in Singapore write vivid compositions in Mandarin, the Chinese ‘mother tongue’. Mastery of the mother tongue by Singaporean students has become an important government priority in recent years. The strategies employed by this study included the use of information and communications technology (ICT mediated scaffolds such as collaborative mind maps and online peer editing to help students learn micro-writing strategies. This paper outlines the process of using various scaffolds to support students to learn and apply the action chain micro-writing strategy. A class of 31 Primary 4 from a neighbourhood school participated in this study. Findings indicated that students were very enthusiastic about writing in the ICT-mediated environment. Contrary to the teacher’s initial belief, students could be scaffolded to write action chains quickly. Findings highlighted the potential of scaffolding students in learning small chunks of writing strategy in an ICT-mediated environment that enabled them to practice these strategies in their composition writing until they could master and apply them. These micro-writing strategies gradually built up to a complex set of skills, including expressive writing. Moreover, students enjoyed working in groups and editing their peers’ work online. This showed that peers could be engaged as scaffolders in the classroom to free up the teacher’ time, allowing the teacher more time to spend with students who were not performing well.

Materializing Mind: The Role of Objects in Cognition and Culture

DEFF Research Database (Denmark)

Tylén, Kristian; McGraw, John J.

2014-01-01

, and distributed cognition, we review and classify a set of cognitive processes mediated by material representations. Specifically, we ask how—in a range of everyday cognitive and cultural practices—we employ objects (1) to scaffold memory, (2) to alter cognitive complexity, (3) to facilitate epistemic......If mind is investigated as the set of interactions that accomplish a cognitive task, that is, if mind is more than that which occurs inside the head, then how does the interplay of biological and environmental resources produce human cognition? Informed by active externalism, joint action...... experimentation, (4) to enable the division of cognitive labor, (5) to promote confidence and trust, (6) to consolidate social structure, and (7) to support dialogical coupling. We conclude that through cultural practices the stable, “manipulable”, and public properties of objects have come to afford...

Ornamenting 3D printed scaffolds with cell-laid extracellular matrix for bone tissue regeneration.

Science.gov (United States)

Pati, Falguni; Song, Tae-Ha; Rijal, Girdhari; Jang, Jinah; Kim, Sung Won; Cho, Dong-Woo

2015-01-01

3D printing technique is the most sophisticated technique to produce scaffolds with tailorable physical properties. But, these scaffolds often suffer from limited biological functionality as they are typically made from synthetic materials. Cell-laid mineralized ECM was shown to be potential for improving the cellular responses and drive osteogenesis of stem cells. Here, we intend to improve the biological functionality of 3D-printed synthetic scaffolds by ornamenting them with cell-laid mineralized extracellular matrix (ECM) that mimics a bony microenvironment. We developed bone graft substitutes by using 3D printed scaffolds made from a composite of polycaprolactone (PCL), poly(lactic-co-glycolic acid) (PLGA), and β-tricalcium phosphate (β-TCP) and mineralized ECM laid by human nasal inferior turbinate tissue-derived mesenchymal stromal cells (hTMSCs). A rotary flask bioreactor was used to culture hTMSCs on the scaffolds to foster formation of mineralized ECM. A freeze/thaw cycle in hypotonic buffer was used to efficiently decellularize (97% DNA reduction) the ECM-ornamented scaffolds while preserving its main organic and inorganic components. The ECM-ornamented 3D printed scaffolds supported osteoblastic differentiation of newly-seeded hTMSCs by upregulating four typical osteoblastic genes (4-fold higher RUNX2; 3-fold higher ALP; 4-fold higher osteocalcin; and 4-fold higher osteopontin) and increasing calcium deposition compared to bare 3D printed scaffolds. In vivo, in ectopic and orthotopic models in rats, ECM-ornamented scaffolds induced greater bone formation than that of bare scaffolds. These results suggest a valuable method to produce ECM-ornamented 3D printed scaffolds as off-the-shelf bone graft substitutes that combine tunable physical properties with physiological presentation of biological signals. Copyright © 2014 Elsevier Ltd. All rights reserved.

A novel surface modification on calcium polyphosphate scaffold for articular cartilage tissue engineering

International Nuclear Information System (INIS)

Lien, S.-M.; Liu, C.-K.; Huang, T.-J.

2007-01-01

The surface of porous three-dimensional (3D) calcium polyphosphate (CPP) scaffold was modified by treatment of quenching-after-sintering in the fabrication process. Scanning electron microscopic examination and degradation tests confirmed a new type of surface modification. A rotary-shaking culture was compared to that of a stationary culture and the results showed that rotary shaking led to enhanced extracellular matrices (ECM) secretion of both proteoglycans and collagen. Rotary-shaking cultured results showed that the quenching-treated CPP scaffold produced a better cartilage tissue, with both proteoglycans and collagen secretions enhanced, than the air-cooled-after-sintering scaffolds. Moreover, β-CPP scaffolds were better for the ECM secretion of both proteoglycans and collagen than the β-CPP + γ-CPP multiphase scaffold. However, the multiphase scaffold led to higher growth rate than that of β-CPP scaffold; the quenching-after-sintering treatment reversed this. In addition, the ECM secretions of both proteoglycans and collagen in the quenching-treated β-CPP scaffold were higher than those in the air-cooled one. Thus, the novel treatment of quenching-after-sintering has shown merits to the porous 3D CPP scaffolds for articular cartilage tissue engineering

The Role of Parents' Distancing Strategies in the Development of Five-Year-Old Children's Theory of Mind

Science.gov (United States)

Galende, Nuria; de Miguel, Manuel Sanchez; Arranz, Enrique

2012-01-01

The aim of this study was to analyse the relation between parents' distancing strategies and the performance of five-year-old children (N = 70) in Theory of Mind (ToM) tasks. The children's performances were assessed during individual sessions held at school. The distancing strategies practiced by the parents (cognitive and linguistic scaffolding,…

Microfibrous silver-coated polymeric scaffolds with tunable mechanical properties

KAUST Repository

Kalakonda, Parvathalu.; Aldhahri, Musab A.; Abdel-wahab, Mohamed Shaaban; Tamayol, Ali; Moghaddam, K. Mollazadeh; Ben Rached, Fathia; Pain, Arnab; Khademhosseini, Ali; Memic, Adnan; Chaieb, Saharoui

2017-01-01

Electrospun scaffolds of poly(glycerol sebacate)/poly(ε-caprolactone) (PGS/PCL) have been used for engineered tissues due to their desirable thermal and mechanical properties as well as their tunable degradability. In this paper, we fabricated micro-fibrous scaffolds from a composite of PGS/PCL using a standard electrospinning method and coated them with silver (Ag). The low temperature coating method prevented substrate melting and the Ag coating decreases the pore size and increases the diameter of fibers which resulted in enhanced thermal and mechanical properties. We further compared the mechanical properties of the composite fibrous scaffolds with different thicknesses of Ag coated scaffolds. The composite fibrous scaffold with a 275 nm Ag coating showed higher tensile modulus (E) and ultimate tensile strength (UTS) without any post-processing treatment. Lastly, potential controlled release of the Ag coating from the composite fibrous scaffolds could present interesting biomedical applications.

Microfibrous silver-coated polymeric scaffolds with tunable mechanical properties

KAUST Repository

Kalakonda, Parvathalu.

2017-07-07

Electrospun scaffolds of poly(glycerol sebacate)/poly(ε-caprolactone) (PGS/PCL) have been used for engineered tissues due to their desirable thermal and mechanical properties as well as their tunable degradability. In this paper, we fabricated micro-fibrous scaffolds from a composite of PGS/PCL using a standard electrospinning method and coated them with silver (Ag). The low temperature coating method prevented substrate melting and the Ag coating decreases the pore size and increases the diameter of fibers which resulted in enhanced thermal and mechanical properties. We further compared the mechanical properties of the composite fibrous scaffolds with different thicknesses of Ag coated scaffolds. The composite fibrous scaffold with a 275 nm Ag coating showed higher tensile modulus (E) and ultimate tensile strength (UTS) without any post-processing treatment. Lastly, potential controlled release of the Ag coating from the composite fibrous scaffolds could present interesting biomedical applications.

Nanorod mediated collagen scaffolds as extra cellular matrix mimics

International Nuclear Information System (INIS)

Vedhanayagam, Mohan; Nair, Balachandran Unni; Sreeram, Kalarical Janardhanan; Mohan, Ranganathan

2015-01-01

Creating collagen scaffolds that mimic extracellular matrices without using toxic exogenous materials remains a big challenge. A new strategy to create scaffolds through end-to-end crosslinking through functionalized nanorods leading to well-designed architecture is presented here. Self-assembled scaffolds with a denaturation temperature of 110 °C, porosity of 70%, pore size of 0.32 μm and Young’s modulus of 231 MPa were developed largely driven by imine bonding between 3-mercapto-1-propanal (MPA) functionalized ZnO nanorods and collagen. The mechanical properties obtained were much higher than that of native collagen, collagen—MPA, collagen—3-mercapto-1-propanol (3MPOH) or collagen- 3-MPOH-ZnO, clearly bringing out the relevance of nanorod mediated assembly of fibrous networks. This new strategy has led to scaffolds with mechanical properties much higher than earlier reports and can provide support for cell growth and facilitation of cell attachment. (paper)

Development of nanofibrous scaffolds containing gum tragacanth/poly (ε-caprolactone) for application as skin scaffolds

Energy Technology Data Exchange (ETDEWEB)

Ranjbar-Mohammadi, Marziyeh [Textile Engineering Department, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Bahrami, S. Hajir, E-mail: hajirb@aut.ac.ir [Textile Engineering Department, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Center for excellence Modern Textile Characterization, Tehran (Iran, Islamic Republic of)

2015-03-01

Outstanding wound healing activity of gum tragacanth (GT) and higher mechanical strength of poly (ε-caprolactone) (PCL) may produce an excellent nanofibrous patch for either skin tissue engineering or wound dressing application. PCL/GT scaffold containing different concentrations of PCL with different blend ratios of GT/PCL was produced using 90% acetic acid as solvent. The results demonstrated that the PCL/GT (3:1.5) with PCL concentration of 20% (w/v) produced nanofibers with proper morphology. Scanning electron microscopy (SEM) and differential scanning calorimetry (DSC) were utilized to characterize the nanofibers. Surface wettability, functional groups analysis, porosity and tensile properties of nanofibers were evaluated. Morphological characterization showed that the addition of GT to PCL solution results in decreasing the average diameter of the PCL/GT nanofibers. However, the hydrophilicity increased in the PCL/GT nanofibers. Slight increase in melting peaks was observed due to the blending of PCL with GT nanofibers. PCL/GT nanofibers were used for in vitro cell culture of human fibroblast cell lines AGO and NIH 3T3 fibroblast cells. MTT assay and SEM results showed that the biocomposite PCL/GT mats enhanced the fibroblast adhesion and proliferation compared to PCL scaffolds. The antibacterial activity of PCL/GT and GT nanofibers against Staphylococcus aureus and Pseudomonas aeruginosa was also examined. - Highlights: • A new skin tissue engineering scaffold from poly (ε-caprolactone) (PCL) and gum tragacanth (GT) has been developed. • These scaffolds might be an effectual simulator of the structure and composition of native skin. • Very slight increase in melting peaks was observed due to the blending of PCL with GT nanofibers. • Biodegradation, water uptake and hydrophilicity properties of these scaffolds showed that produced scaffolds were adherent. • The electrospun PCL/GT scaffold can promote the skin regeneration of full

Development of nanofibrous scaffolds containing gum tragacanth/poly (ε-caprolactone) for application as skin scaffolds

International Nuclear Information System (INIS)

Ranjbar-Mohammadi, Marziyeh; Bahrami, S. Hajir

2015-01-01

Outstanding wound healing activity of gum tragacanth (GT) and higher mechanical strength of poly (ε-caprolactone) (PCL) may produce an excellent nanofibrous patch for either skin tissue engineering or wound dressing application. PCL/GT scaffold containing different concentrations of PCL with different blend ratios of GT/PCL was produced using 90% acetic acid as solvent. The results demonstrated that the PCL/GT (3:1.5) with PCL concentration of 20% (w/v) produced nanofibers with proper morphology. Scanning electron microscopy (SEM) and differential scanning calorimetry (DSC) were utilized to characterize the nanofibers. Surface wettability, functional groups analysis, porosity and tensile properties of nanofibers were evaluated. Morphological characterization showed that the addition of GT to PCL solution results in decreasing the average diameter of the PCL/GT nanofibers. However, the hydrophilicity increased in the PCL/GT nanofibers. Slight increase in melting peaks was observed due to the blending of PCL with GT nanofibers. PCL/GT nanofibers were used for in vitro cell culture of human fibroblast cell lines AGO and NIH 3T3 fibroblast cells. MTT assay and SEM results showed that the biocomposite PCL/GT mats enhanced the fibroblast adhesion and proliferation compared to PCL scaffolds. The antibacterial activity of PCL/GT and GT nanofibers against Staphylococcus aureus and Pseudomonas aeruginosa was also examined. - Highlights: • A new skin tissue engineering scaffold from poly (ε-caprolactone) (PCL) and gum tragacanth (GT) has been developed. • These scaffolds might be an effectual simulator of the structure and composition of native skin. • Very slight increase in melting peaks was observed due to the blending of PCL with GT nanofibers. • Biodegradation, water uptake and hydrophilicity properties of these scaffolds showed that produced scaffolds were adherent. • The electrospun PCL/GT scaffold can promote the skin regeneration of full

Annealing free, clean graphene transfer using alternative polymer scaffolds.

Science.gov (United States)

Wood, Joshua D; Doidge, Gregory P; Carrion, Enrique A; Koepke, Justin C; Kaitz, Joshua A; Datye, Isha; Behnam, Ashkan; Hewaparakrama, Jayan; Aruin, Basil; Chen, Yaofeng; Dong, Hefei; Haasch, Richard T; Lyding, Joseph W; Pop, Eric

2015-02-06

We examine the transfer of graphene grown by chemical vapor deposition (CVD) with polymer scaffolds of poly(methyl methacrylate) (PMMA), poly(lactic acid) (PLA), poly(phthalaldehyde) (PPA), and poly(bisphenol A carbonate) (PC). We find that optimally reactive PC scaffolds provide the cleanest graphene transfers without any annealing, after extensive comparison with optical microscopy, x-ray photoelectron spectroscopy, atomic force microscopy, and scanning tunneling microscopy. Comparatively, films transferred with PLA, PPA, PMMA/PC, and PMMA have a two-fold higher roughness and a five-fold higher chemical doping. Using PC scaffolds, we demonstrate the clean transfer of CVD multilayer graphene, fluorinated graphene, and hexagonal boron nitride. Our annealing free, PC transfers enable the use of atomically-clean nanomaterials in biomolecule encapsulation and flexible electronic applications.

Annealing free, clean graphene transfer using alternative polymer scaffolds

International Nuclear Information System (INIS)

Wood, Joshua D; Doidge, Gregory P; Carrion, Enrique A; Koepke, Justin C; Datye, Isha; Behnam, Ashkan; Hewaparakrama, Jayan; Aruin, Basil; Chen, Yaofeng; Lyding, Joseph W; Kaitz, Joshua A; Dong, Hefei; Haasch, Richard T; Pop, Eric

2015-01-01

We examine the transfer of graphene grown by chemical vapor deposition (CVD) with polymer scaffolds of poly(methyl methacrylate) (PMMA), poly(lactic acid) (PLA), poly(phthalaldehyde) (PPA), and poly(bisphenol A carbonate) (PC). We find that optimally reactive PC scaffolds provide the cleanest graphene transfers without any annealing, after extensive comparison with optical microscopy, x-ray photoelectron spectroscopy, atomic force microscopy, and scanning tunneling microscopy. Comparatively, films transferred with PLA, PPA, PMMA/PC, and PMMA have a two-fold higher roughness and a five-fold higher chemical doping. Using PC scaffolds, we demonstrate the clean transfer of CVD multilayer graphene, fluorinated graphene, and hexagonal boron nitride. Our annealing free, PC transfers enable the use of atomically-clean nanomaterials in biomolecule encapsulation and flexible electronic applications. (paper)

The distracted mind on the wheel: Overall propensity to mind wandering is associated with road crash responsibility

OpenAIRE

Gil-Jardin?, C?dric; N?e, M?lanie; Lagarde, Emmanuel; Schooler, Jonathan; Contrand, Benjamin; Orriols, Ludivine; Galera, C?dric

2017-01-01

The role of distractions on attentional lapses that place road users in higher risk of crash remains poorly understood. We aimed to assess the respective impact of (i) mind wandering trait (propensity to mind wander in the everyday life as measured with a set of 4 questions on the proportion of time spent mind wandering in 4 different situations) and (ii) mind wandering state (disturbing thoughts just before the crash) on road crash risk using a comparison between responsible and non-responsi...

Schizotypy and mindfulness: Magical thinking without suspiciousness characterizes mindfulness meditators

Directory of Open Access Journals (Sweden)

Elena Antonova

2016-09-01

Full Text Available Despite growing evidence for demonstrated efficacy of mindfulness in various disorders, there is a continuous concern about the relationship between mindfulness practice and psychosis. As schizotypy is part of the psychosis spectrum, we examined the relationship between long-term mindfulness practice and schizotypy in two independent studies. Study 1 included 24 experienced mindfulness practitioners (19 males from the Buddhist tradition (meditators and 24 meditation-naïve individuals (all males. Study 2 consisted of 28 meditators and 28 meditation-naïve individuals (all males. All participants completed the Schizotypal Personality Questionnaire (Raine, 1991, a self-report scale containing 9 subscales (ideas of reference, excessive social anxiety, magical thinking, unusual perceptual experiences, odd/eccentric behavior, no close friends, odd speech, constricted affect, suspiciousness. Participants of study 2 also completed the Five-Facet Mindfulness Questionnaire which assesses observing (Observe, describing (Describe, acting with awareness (Awareness, non-judging of (Non-judgment and non-reactivity to inner experience (Non-reactivity facets of trait mindfulness. In both studies, meditators scored significantly lower on suspiciousness and higher on magical thinking compared to meditation-naïve individuals and showed a trend towards lower scores on excessive social anxiety. Excessive social anxiety correlated negatively with Awareness and Non-judgment; and suspiciousness with Awareness, Non-judgment and Non-reactivity facets across both groups. The two groups did not differ in their total schizotypy score. We conclude that mindfulness practice is not associated with an overall increase in schizotypal traits. Instead, the pattern suggests that mindfulness meditation, particularly with an emphasis on the Awareness, Non-judgment and Non-reactivity aspects, may help to reduce suspiciousness and excessive social anxiety.

Novel fiber-based pure chitosan scaffold for tendon augmentation: biomechanical and cell biological evaluation.

Science.gov (United States)

Nowotny, J; Aibibu, D; Farack, J; Nimtschke, U; Hild, M; Gelinsky, M; Kasten, P; Cherif, Ch

2016-07-01

One possibility to improve the mechanical properties after tendon ruptures is augmentation with a scaffold. Based on wet spinning technology, chitosan fibres were processed to a novel pure high-grade multifilament yarn with reproducible quality. The fibres were braided to obtain a 3D tendon scaffold. The CS fibres and scaffolds were evaluated biomechanically and compared to human supraspinatus (SSP) tendons. For the cytobiological characterization, in vitro cell culture experiments with human mesenchymal stem cells (hMSC) were performed. Three types of 3D circular braided scaffolds were fabricated. Significantly, higher ultimate stress values were measured for scaffold with larger filament yarn, compared to scaffold with smaller filament yarn. During cultivation over 28 days, the cells showed in dependence of isolation method and/or donor a doubling or tripling of the cell number or even a six-fold increase on the CS scaffold, which was comparable to the control (polystyrene) or in the case of cells obtained from human biceps tendon even higher proliferation rates. After 14 days, the scaffold surface was covered homogeneously with a cell layer. In summary, the present work demonstrates that braided chitosan scaffolds constitute a straightforward approach for designing tendon analogues, maintaining important flexibility in scaffold design and providing favourable mechanical properties of the resulting construct.

Does Mindfulness Enhance Critical Thinking? Evidence for the Mediating Effects of Executive Functioning in the Relationship between Mindfulness and Critical Thinking

OpenAIRE

Noone, Chris; Bunting, Brendan; Hogan, Michael J.

2016-01-01

Mindfulness originated in the Buddhist tradition as a way of cultivating clarity of thought. Despite the fact that this behaviour is best captured using critical thinking assessments, no studies have examined the effects of mindfulness on critical thinking or the mechanisms underlying any such possible relationship. Even so, mindfulness has been suggested as being beneficial for critical thinking in higher education. Critical thinking is recognised as an important higher-order cognitive proce...

A Moment of Mindfulness: Computer-Mediated Mindfulness Practice Increases State Mindfulness.

Directory of Open Access Journals (Sweden)

Lynsey Mahmood

Full Text Available Three studies investigated the use of a 5-minute, computer-mediated mindfulness practice in increasing levels of state mindfulness. In Study 1, 54 high school students completed the computer-mediated mindfulness practice in a lab setting and Toronto Mindfulness Scale (TMS scores were measured before and after the practice. In Study 2 (N = 90 and Study 3 (N = 61, the mindfulness practice was tested with an entirely online sample to test the delivery of the 5-minute mindfulness practice via the internet. In Study 2 and 3, we found a significant increase in TMS scores in the mindful condition, but not in the control condition. These findings highlight the impact of a brief, mindfulness practice for single-session, computer-mediated use to increase mindfulness as a state.

Bioactive glass-reinforced bioceramic ink writing scaffolds: sintering, microstructure and mechanical behavior.

Science.gov (United States)

Shao, Huifeng; Yang, Xianyan; He, Yong; Fu, Jianzhong; Liu, Limin; Ma, Liang; Zhang, Lei; Yang, Guojing; Gao, Changyou; Gou, Zhongru

2015-09-10

The densification of pore struts in bioceramic scaffolds is important for structure stability and strength reliability. An advantage of ceramic ink writing is the precise control over the microstructure and macroarchitecture. However, the use of organic binder in such ink writing process would heavily affect the densification of ceramic struts and sacrifice the mechanical strength of porous scaffolds after sintering. This study presents a low-melt-point bioactive glass (BG)-assisted sintering strategy to overcome the main limitations of direct ink writing (extrusion-based three-dimensional printing) and to produce high-strength calcium silicate (CSi) bioceramic scaffolds. The 1% BG-added CSi (CSi-BG1) scaffolds with rectangular pore morphology sintered at 1080 °C have a very small BG content, readily induce apatite formation, and show appreciable linear shrinkage (∼21%), which is consistent with the composite scaffolds with less or more BG contents sintered at either the same or a higher temperature. These CSi-BG1 scaffolds also possess a high elastic modulus (∼350 MPa) and appreciable compressive strength (∼48 MPa), and show significant strength enhancement after exposure to simulated body fluid-a performance markedly superior to those of pure CSi scaffolds. Particularly, the honeycomb-pore CSi-BG1 scaffolds show markedly higher compressive strength (∼88 MPa) than the scaffolds with rectangular, parallelogram, and Archimedean chord pore structures. It is suggested that this approach can potentially facilitate the translation of ceramic ink writing and BG-assisted sintering of bioceramic scaffold technologies to the in situ bone repair.

Fabrication of highly porous biodegradable biomimetic nanocomposite as advanced bone tissue scaffold

Directory of Open Access Journals (Sweden)

Abdalla Abdal-hay

2017-02-01

Full Text Available Development of bioinspired or biomimetic materials is currently a challenge in the field of tissue regeneration. In-situ 3D biomimetic microporous nanocomposite scaffold has been developed using a simple lyophilization post hydrothermal reaction for bone healing applications. The fabricated 3D porous scaffold possesses advantages of good bonelike apatite particles distribution, thermal properties and high porous interconnected network structure. High dispersion bonelike apatite nanoparticles (NPs rapidly nucleated and deposited from surrounding biological minerals within chitosan (CTS matrices using hydrothermal technique. After that, freeze-drying method was applied on the composite solution to form the desired porous 3D architecture. Interestingly, the porosity and pore size of composite scaffold were not significantly affected by the particles size and particles content within the CTS matrix. Our results demonstrated that the compression modulus of porous composite scaffold is twice higher than that of plain CTS scaffold, indicating a maximization of the chemical interaction between polymer matrix and apatite NPs. Cytocompatibility test for MC3T3-E1 pre-osteoblasts cell line using MTT-indirect assay test showed that the fabricated 3D microporous nanocomposite scaffold possesses higher cell proliferation and growth than that of pure CTS scaffold. Collectively, our results suggest that the newly developed highly porous apatite/CTS nanocomposite scaffold as an alternative of hydroxyapatite/CTS scaffold may serve as an excellent porous 3D platform for bone tissue regeneration.

Effects of scaffold surface morphology on cell adhesion and survival rate in vitreous cryopreservation of tenocyte-scaffold constructs

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Wang, Zhi [State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu 610041 (China); Department of Bone and Joint Surgery, The affiliated hospital of Luzhou Medical College, Luzhou 646000 (China); Qing, Quan [Sichuan College of Traditional Chinese Medicine, Mianyang 621000 (China); Regenerative Medicine Research Center, West China Hospital of Sichuan University, Chengdu 610041 (China); Chen, Xi; Liu, Cheng-Jun; Luo, Jing-Cong [State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu 610041 (China); Hu, Jin-Lian [Institute of Textiles and Clothing, The Hong Kong Polytechnic University, Hong Kong (China); Qin, Ting-Wu, E-mail: tingwuqin@hotmail.com [State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu 610041 (China)

2016-12-01

Highlights: • The shapes of tenocytes varied when seeded on different surface of scaffolds. • Tenocytes were flat on smooth surface and spindle on micro-grooved surface. • Tenocytes were ellipse or spindle on porous surface. • Tenocytes got varying adhesion shape and elongation index on varying surfaces. • The tenocyte survival on porous surface was superior to the other two groups. - Abstract: The purpose of this study was to investigate the effects of scaffold surface morphology on cell adhesion and survival rate in vitreous cryopreservation of tenocyte-scaffold constructs. Tenocytes were obtained from tail tendons of rats. Polydimethylsiloxane (PDMS) was used to fabricate three types of scaffolds with varying surface morphological characteristics, i.e., smooth, micro-grooved, and porous surfaces, respectively. The tenocytes were seeded on the surfaces of the scaffolds to form tenocyte-scaffold constructs. The constructs were cryopreserved in a vitreous cryoprotectant (CPA) with a multi-step protocol. The cell adhesion to scaffolds was observed with electronic scanning microscopy (SEM). The elongation index of the living tenocytes and ratio of live/dead cell number were examined based on a live/dead dual fluorescent staining technique, and the survival rate of tenocytes was studied with flow cytometry (FC). The results showed the shapes of tenocytes varied between the different groups: flat or polygonal (on smooth surface), spindle (on micro-grooved surface), and spindle or ellipse (on porous surface). After thawing, the porous surface got the most living tenocytes and a higher survival rate, suggesting its potential application for vitreous cryopreservation of engineered tendon constructs.

Rheological, biocompatibility and osteogenesis assessment of fish collagen scaffold for bone tissue engineering.

Science.gov (United States)

Elango, Jeevithan; Zhang, Jingyi; Bao, Bin; Palaniyandi, Krishnamoorthy; Wang, Shujun; Wenhui, Wu; Robinson, Jeya Shakila

2016-10-01

In the present investigation, an attempt was made to find an alternative to mammalian collagen with better osteogenesis ability. Three types of collagen scaffolds - collagen, collagen-chitosan (CCH), and collagen-hydroxyapatite (CHA) - were prepared from the cartilage of Blue shark and investigated for their physico-functional and mechanical properties in relation to biocompatibility and osteogenesis. CCH scaffold was superior with pH 4.5-4.9 and viscosity 9.7-10.9cP. Notably, addition of chitosan and HA (hydroxyapatite) improved the stiffness (11-23MPa) and degradation rate but lowered the water binding capacity and porosity of the scaffold. Interestingly, CCH scaffolds remained for 3days before complete in-vitro biodegradation. The decreased amount of viable T-cells and higher level of FAS/APO-1 were substantiated the biocompatibility properties of prepared collagen scaffolds. Osteogenesis study revealed that the addition of CH and HA in both fish and mammalian collagen scaffolds could efficiently promote osteoblast cell formation. The ALP activity was significantly high in CHA scaffold-treated osteoblast cells, which suggests an enhanced bone-healing process. Therefore, the present study concludes that the composite scaffolds prepared from fish collagen with higher stiffness, lower biodegradation rate, better biocompatible, and osteogenesis properties were suitable biomaterial for a bone tissue engineering application as an alternative to mammalian collagen scaffolds. Copyright © 2016 Elsevier B.V. All rights reserved.

Oxygen Plasma Treatment on 3D-Printed Chitosan/Gelatin/Hydroxyapatite Scaffolds for Bone Tissue Engineering.

Science.gov (United States)

Lee, Chang-Min; Yang, Seong-Won; Jung, Sang-Chul; Kim, Byung-Hoon

2017-04-01

The 3D hydroxyapatite/gelatin/chitosan composite scaffolds were fabricated by 3D printing technique. The scaffolds were treated by oxygen plasma to improve the bioactivity and its surface characterization and in vitro cell culture were investigated. The scaffolds exhibited the good porosity and interconnectivity of pores. After oxygen plasma etching, roughness and wettability on the scaffolds surface are increased. Plasma treated scaffolds showed higher proliferation than that of untreated scaffolds. Oxygen plasma treatment could be used as potential tool to enhance the biocompatibility on the 3D composite scaffolds.

Tough and flexible CNT-polymeric hybrid scaffolds for engineering cardiac constructs.

Science.gov (United States)

Kharaziha, Mahshid; Shin, Su Ryon; Nikkhah, Mehdi; Topkaya, Seda Nur; Masoumi, Nafiseh; Annabi, Nasim; Dokmeci, Mehmet R; Khademhosseini, Ali

2014-08-01

In the past few years, a considerable amount of effort has been devoted toward the development of biomimetic scaffolds for cardiac tissue engineering. However, most of the previous scaffolds have been electrically insulating or lacked the structural and mechanical robustness to engineer cardiac tissue constructs with suitable electrophysiological functions. Here, we developed tough and flexible hybrid scaffolds with enhanced electrical properties composed of carbon nanotubes (CNTs) embedded aligned poly(glycerol sebacate):gelatin (PG) electrospun nanofibers. Incorporation of varying concentrations of CNTs from 0 to 1.5% within the PG nanofibrous scaffolds (CNT-PG scaffolds) notably enhanced fiber alignment and improved the electrical conductivity and toughness of the scaffolds while maintaining the viability, retention, alignment, and contractile activities of cardiomyocytes (CMs) seeded on the scaffolds. The resulting CNT-PG scaffolds resulted in stronger spontaneous and synchronous beating behavior (3.5-fold lower excitation threshold and 2.8-fold higher maximum capture rate) compared to those cultured on PG scaffold. Overall, our findings demonstrated that aligned CNT-PG scaffold exhibited superior mechanical properties with enhanced CM beating properties. It is envisioned that the proposed hybrid scaffolds can be useful for generating cardiac tissue constructs with improved organization and maturation. Copyright © 2014 Elsevier Ltd. All rights reserved.

A Moment of Mindfulness: Computer-Mediated Mindfulness Practice Increases State Mindfulness

OpenAIRE

Mahmood, L.; Hopthrow, T.; Randsley de Moura, G.

2016-01-01

Three studies investigated the use of a 5-minute, computer-mediated mindfulness practice in increasing levels of state mindfulness. In Study 1, 54 high school students completed the computer-mediated mindfulness practice in a lab setting and Toronto Mindfulness Scale (TMS) scores were measured before and after the practice. In Study 2 (N = 90) and Study 3 (N = 61), the mindfulness practice was tested with an entirely online sample to test the delivery of the 5-minute mindfulness practice via ...

Magnetic responsive hydroxyapatite composite scaffolds construction for bone defect reparation.

Science.gov (United States)

Zeng, Xiao Bo; Hu, Hao; Xie, Li Qin; Lan, Fang; Jiang, Wen; Wu, Yao; Gu, Zhong Wei

2012-01-01

In recent years, interest in magnetic biomimetic scaffolds for tissue engineering has increased considerably. A type of magnetic scaffold composed of magnetic nanoparticles (MNPs) and hydroxyapatite (HA) for bone repair has been developed by our research group. In this study, to investigate the influence of the MNP content (in the scaffolds) on the cell behaviors and the interactions between the magnetic scaffold and the exterior magnetic field, a series of MNP-HA magnetic scaffolds with different MNP contents (from 0.2% to 2%) were fabricated by immersing HA scaffold into MNP colloid. ROS 17/2.8 and MC3T3-E1 cells were cultured on the scaffolds in vitro, with and without an exterior magnetic field, respectively. The cell adhesion, proliferation and differentiation were evaluated via scanning electron microscopy; confocal laser scanning microscopy; and 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), alkaline phosphatase, and bone gla protein activity tests. The results demonstrated the positive influence of the magnetic scaffolds on cell adhesion, proliferation, and differentiation. Further, a higher amount of MNPs on the magnetic scaffolds led to more significant stimulation. The magnetic scaffold can respond to the exterior magnetic field and engender some synergistic effect to intensify the stimulating effect of a magnetic field to the proliferation and differentiation of cells.

Fabrication and characterization of platelet-rich plasma scaffolds for tissue engineering applications

Energy Technology Data Exchange (ETDEWEB)

Sadeghi-Ataabadi, Mahmoud [Tissue engineering Lab, Anatomy department, Medical School, Shiraz University of Medical Sciences (Iran, Islamic Republic of); Mostafavi-pour, Zohreh [Recombinant protein lab, Department of Biochemistry, Medical School, Shiraz University of Medical Sciences (Iran, Islamic Republic of); Vojdani, Zahra; Sani, Mahsa [Tissue engineering Lab, Anatomy department, Medical School, Shiraz University of Medical Sciences (Iran, Islamic Republic of); Latifi, Mona [Tissue Engineering Department, National Institute of Genetic Engineering and Biotechnoloy (Iran, Islamic Republic of); Tissue engineering Lab, Anatomy department, Medical School, Shiraz University of Medical Sciences (Iran, Islamic Republic of); Talaei-Khozani, Tahereh, E-mail: talaeit@sums.ac.ir [Tissue engineering Lab, Anatomy department, Medical School, Shiraz University of Medical Sciences (Iran, Islamic Republic of)

2017-02-01

Platelet-Rich Plasma (PRP), as a rich source of growth factor, can form a fibrin gel that recapitulates the extracellular matrix of the tissues. The aim of this study was to evaluate the effects of different concentrations of CaCl{sub 2} on the PRP scaffold structure which in turn could change the cell's behavior. PRP was mixed with 2.5, 5 and 10% (w/v) CaCl{sub 2}. Then, the tensile strength, biodegradability and water content of the scaffolds were evaluated. We also performed immunostaining for assessment of the actin stress fiber orientation and SEM for detecting the cell phenotype and physical properties of the fibers. Cell viability, attachment and migration were also evaluated. The highest cell attachment and short term proliferation rate was observed on the scaffolds with 2.5% CaCl{sub 2}. The cells cultured on the scaffold with higher CaCl{sub 2} concentration had fusiform phenotype with few cell processes and parallel arrangement of stress fibers while those cultured on the other scaffolds were fibroblast-like with more processes and net-like stress fibers. The scaffolds with 10% CaCl{sub 2} demonstrated the highest osmolarity (358.75 ± 4.99 mOsmole), fiber thickness (302.1 ± 54.3 nm), pore size (332.1 ± 118.9 nm{sup 2}) and the longest clotting time (12.2 ± 0.776 min) compared with the other scaffolds. Water content, branching angle, porosity, orientation and tensile strength did not change by gelation with different CaCl{sub 2} concentrations. In conclusion, the cell shape, viability and proliferation were modified by culturing on the PRP scaffolds prepared with various concentrations of CaCl{sub 2}, and as a result, the scaffolds showed different physical and biological properties - Highlights: Platelet rich plasma (PRP) can be considered as an autologous source for tissue engineering applications. Cell shape, function and differentiation fate are influenced by the mechanical and physical features of the scaffolds. Different CaCl2

Fabrication and characterization of platelet-rich plasma scaffolds for tissue engineering applications

International Nuclear Information System (INIS)

Sadeghi-Ataabadi, Mahmoud; Mostafavi-pour, Zohreh; Vojdani, Zahra; Sani, Mahsa; Latifi, Mona; Talaei-Khozani, Tahereh

2017-01-01

Platelet-Rich Plasma (PRP), as a rich source of growth factor, can form a fibrin gel that recapitulates the extracellular matrix of the tissues. The aim of this study was to evaluate the effects of different concentrations of CaCl 2 on the PRP scaffold structure which in turn could change the cell's behavior. PRP was mixed with 2.5, 5 and 10% (w/v) CaCl 2 . Then, the tensile strength, biodegradability and water content of the scaffolds were evaluated. We also performed immunostaining for assessment of the actin stress fiber orientation and SEM for detecting the cell phenotype and physical properties of the fibers. Cell viability, attachment and migration were also evaluated. The highest cell attachment and short term proliferation rate was observed on the scaffolds with 2.5% CaCl 2 . The cells cultured on the scaffold with higher CaCl 2 concentration had fusiform phenotype with few cell processes and parallel arrangement of stress fibers while those cultured on the other scaffolds were fibroblast-like with more processes and net-like stress fibers. The scaffolds with 10% CaCl 2 demonstrated the highest osmolarity (358.75 ± 4.99 mOsmole), fiber thickness (302.1 ± 54.3 nm), pore size (332.1 ± 118.9 nm 2 ) and the longest clotting time (12.2 ± 0.776 min) compared with the other scaffolds. Water content, branching angle, porosity, orientation and tensile strength did not change by gelation with different CaCl 2 concentrations. In conclusion, the cell shape, viability and proliferation were modified by culturing on the PRP scaffolds prepared with various concentrations of CaCl 2 , and as a result, the scaffolds showed different physical and biological properties - Highlights: Platelet rich plasma (PRP) can be considered as an autologous source for tissue engineering applications. Cell shape, function and differentiation fate are influenced by the mechanical and physical features of the scaffolds. Different CaCl2 concentrations modified some features of the PRP

PHBV/PAM scaffolds with local oriented structure through UV polymerization for tissue engineering.

Science.gov (United States)

Ke, Yu; Wu, Gang; Wang, Yingjun

2014-01-01

Locally oriented tissue engineering scaffolds can provoke cellular orientation and direct cell spread and migration, offering an exciting potential way for the regeneration of the complex tissue. Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) scaffolds with locally oriented hydrophilic polyacrylamide (PAM) inside the macropores of the scaffolds were achieved through UV graft polymerization. The interpenetrating PAM chains enabled good interconnectivity of PHBV/PAM scaffolds that presented a lower porosity and minor diameter of pores than PHBV scaffolds. The pores with diameter below 100  μm increased to 82.15% of PHBV/PAM scaffolds compared with 31.5% of PHBV scaffolds. PHBV/PAM scaffold showed a much higher compressive elastic modulus than PHBV scaffold due to PAM stuffing. At 5 days of culturing, sheep chondrocytes spread along the similar direction in the macropores of PHBV/PAM scaffolds. The locally oriented PAM chains might guide the attachment and spreading of chondrocytes and direct the formation of microfilaments via contact guidance.

Strong and biocompatible three-dimensional porous silk fibroin/graphene oxide scaffold prepared by phase separation.

Science.gov (United States)

Wang, Shu-Dong; Ma, Qian; Wang, Ke; Ma, Pi-Bo

2018-05-01

Silk fibroin (SF) is blended with graphene oxide (GO) to prepare the strong and biocompatible three dimensional porous SF/GO blended scaffold via phase separation. GO could be well dispersed in SF solution and GO could also be well distributed in the SF scaffold. Furthermore, the introduction of GO can lead to structural change in the bended scaffold. Higher concentration of GO resulted in more compact structure and smaller pore size of the composite scaffolds without decreasing their porosity. Scanning electron microscopy and energy dispersive spectrometry results also reveal that SF and GO are homogeneous blended together. Analysis of chemical structures of the scaffold shows that addition of GO do not affect the crystalline structure of SF and it is evenly blended with SF. The blended scaffold has significantly higher breaking strength than the pure SF scaffold. In vitro study indicates that both pure SF scaffold and SF/GO composite scaffold support growth and proliferation of MC3T3-E1 osteoprogenitor cells. However, the addition of GO contribute to the proliferation of MC3T3-E1 osteoprogenitor. The testing results show that the blended scaffold is an appropriate candidate for tissue engineering. Copyright © 2018 Elsevier B.V. All rights reserved.

Development of Collagen/Demineralized Bone Powder Scaffolds and Periosteum-Derived Cells for Bone Tissue Engineering Application

Directory of Open Access Journals (Sweden)

Wilairat Leeanansaksiri

2013-01-01

Full Text Available The aim of this study was to investigate physical and biological properties of collagen (COL and demineralized bone powder (DBP scaffolds for bone tissue engineering. DBP was prepared and divided into three groups, based on various particle sizes: 75–125 µm, 125–250 µm, and 250–500 µm. DBP was homogeneously mixed with type I collagen and three-dimensional scaffolds were constructed, applying chemical crosslinking and lyophilization. Upon culture with human periosteum-derived cells (PD cells, osteogenic differentiation of PD cells was investigated using alkaline phosphatase (ALP activity and calcium assay kits. The physical properties of the COL/DBP scaffolds were obviously different from COL scaffolds, irrespective of the size of DBP. In addition, PD cells cultured with COL scaffolds showed significantly higher cell adhesion and proliferation than those with COL/DBP scaffolds. In contrast, COL/DBP scaffolds exhibited greater osteoinductive potential than COL scaffolds. The PD cells with COL/DBP scaffolds possessed higher ALP activity than those with COL scaffolds. PD cells cultured with COL/DBP scaffolds with 250–500 mm particle size yielded the maximum calcium deposition. In conclusion, PD cells cultured on the scaffolds could exhibit osteoinductive potential. The composite scaffold of COL/DBP with 250–500 mm particle size could be considered a potential bone tissue engineering implant.

Mesenchymal stem cell ingrowth and differentiation on coralline hydroxyapatite scaffolds

DEFF Research Database (Denmark)

Mygind, Tina; Stiehler, Maik; Baatrup, Anette

2007-01-01

Culture of osteogenic cells on a porous scaffold could offer a new solution to bone grafting using autologous human mesenchymal stem cells (hMSC) from the patient. We compared coralline hydroxyapatite scaffolds with pore sizes of 200 and 500 microm for expansion and differentiation of hMSCs. We...... polymerase chain reaction for 10 osteogenic markers. The 500-microm scaffolds had increased proliferation rates and accommodated a higher number of cells (shown by DNA content, scanning electron microscopy and fluorescence microscopy). Thus the porosity of a 3D microporous biomaterial may be used to steer h......MSC in a particular direction. We found that dynamic spinner flask cultivation of hMSC/scaffold constructs resulted in increased proliferation, differentiation and distribution of cells in scaffolds. Therefore, spinner flask cultivation is an easy-to-use inexpensive system for cultivating hMSCs on small...

Biomimetic composite coating on rapid prototyped scaffolds for bone tissue engineering.

Science.gov (United States)

Arafat, M Tarik; Lam, Christopher X F; Ekaputra, Andrew K; Wong, Siew Yee; Li, Xu; Gibson, Ian

2011-02-01

The objective of this present study was to improve the functional performance of rapid prototyped scaffolds for bone tissue engineering through biomimetic composite coating. Rapid prototyped poly(ε-caprolactone)/tri-calcium phosphate (PCL/TCP) scaffolds were fabricated using the screw extrusion system (SES). The fabricated PCL/TCP scaffolds were coated with a carbonated hydroxyapatite (CHA)-gelatin composite via biomimetic co-precipitation. The structure of the prepared CHA-gelatin composite coating was studied by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. Compressive mechanical testing revealed that the coating process did not have any detrimental effect on the mechanical properties of the scaffolds. The cell-scaffold interaction was studied by culturing porcine bone marrow stromal cells (BMSCs) on the scaffolds and assessing the proliferation and bone-related gene and protein expression capabilities of the cells. Confocal laser microscopy and SEM images of the cell-scaffold constructs showed a uniformly distributed cell sheet and accumulation of extracellular matrix in the interior of CHA-gelatin composite-coated PCL/TCP scaffolds. The proliferation rate of BMSCs on CHA-gelatin composite-coated PCL/TCP scaffolds was about 2.3 and 1.7 times higher than that on PCL/TCP scaffolds and CHA-coated PCL/TCP scaffolds, respectively, by day 10. Furthermore, reverse transcription polymerase chain reaction and Western blot analysis revealed that CHA-gelatin composite-coated PCL/TCP scaffolds stimulate osteogenic differentiation of BMSCs the most, compared with PCL/TCP scaffolds and CHA-coated PCL/TCP scaffolds. These results demonstrate that CHA-gelatin composite-coated rapid prototyped PCL/TCP scaffolds are promising for bone tissue engineering. Copyright © 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Mindfulness

DEFF Research Database (Denmark)

Chiesa, Alberto; Serretti, Alessandro; Jakobsen, Janus Christian

2013-01-01

The beneficial clinical effects of mindfulness practices are receiving increasing support from empirical studies. However, the functional neural mechanisms underlying these benefits have not been thoroughly investigated. Some authors suggest that mindfulness should be described as a 'top......-down' emotion regulation strategy, while others suggest that mindfulness should be described as a 'bottom-up' emotion regulation strategy. Current discrepancies might derive from the many different descriptions and applications of mindfulness. The present review aims to discuss current descriptions...... of mindfulness and the relationship existing between mindfulness practice and most commonly investigated emotion regulation strategies. Recent results from functional neuro-imaging studies investigating mindfulness training within the context of emotion regulation are presented. We suggest that mindfulness...

Does mindfulness enhance critical thinking? Evidence for the mediating effects of executive functioning in the relationship between mindfulness and critical thinking

Directory of Open Access Journals (Sweden)

Chris eNoone

2016-01-01

Full Text Available Mindfulness originated in the Buddhist tradition as a way of cultivating clarity of thought. Despite the fact that this behaviour is best captured using critical thinking assessments, no studies have examined the effects of mindfulness on critical thinking or the mechanisms underlying any such possible relationship. Even so, mindfulness has been suggested as being beneficial for critical thinking in higher education. Critical thinking is recognised as an important higher-order cognitive process which involves the ability to analyse and evaluate evidence and arguments. Such non-automatic, reflective responses generally require the engagement of executive functioning which includes updating, inhibition and shifting of representations in working memory. Based on research showing that mindfulness enhances aspects of executive functioning and certain higher-order cognitive processes, we hypothesised that individuals higher in facets of dispositional mindfulness would demonstrate greater critical thinking performance, and that this relationship would be mediated by executive functioning. Cross-sectional assessment of these constructs in a sample of 178 university students was achieved using the observing and non-reactivity sub-scales of the Five Factor Mindfulness Questionnaire, a battery of executive functioning tasks and the Halpern Critical Thinking Assessment. Our hypotheses were tested by constructing a multiple meditation model which was analysed using Structural Equation Modelling. Evidence was found for inhibition mediating the relationships between both observing and non-reactivity and critical thinking in different ways. Indirect-only (or full mediation was demonstrated for the relationship between observing, inhibition and critical thinking. Competitive mediation was demonstrated for the relationship between non-reactivity, inhibition and critical thinking. This suggests additional mediators of the relationship between non-reactivity and

Human-like collagen/nano-hydroxyapatite scaffolds for the culture of chondrocytes

Energy Technology Data Exchange (ETDEWEB)

Jia, Liping; Duan, Zhiguang [Shaanxi Key Laboratory of Degradable Biomedical Materials, Northwest University, 229 Taibai North Road, Xi' an, Shaanxi 710069 (China); Shaanxi R and D Center of Biomaterials and Fermentation Engineering, Northwest University, 229 Taibai North Road, Xi' an, Shaanxi 710069 (China); Fan, Daidi, E-mail: fandaidi@nwu.edu.cn [Shaanxi Key Laboratory of Degradable Biomedical Materials, Northwest University, 229 Taibai North Road, Xi' an, Shaanxi 710069 (China); Shaanxi R and D Center of Biomaterials and Fermentation Engineering, Northwest University, 229 Taibai North Road, Xi' an, Shaanxi 710069 (China); Mi, Yu; Hui, Junfeng [Shaanxi Key Laboratory of Degradable Biomedical Materials, Northwest University, 229 Taibai North Road, Xi' an, Shaanxi 710069 (China); Shaanxi R and D Center of Biomaterials and Fermentation Engineering, Northwest University, 229 Taibai North Road, Xi' an, Shaanxi 710069 (China); Chang, Le [School of Chemical Engineering, Northwest University, Xi' an, Shaanxi 710069 (China)

2013-03-01

Three dimensional (3D) biodegradable porous scaffolds play a key role in cartilage tissue repair. Freeze-drying and cross-linking techniques were used to fabricate a 3D composite scaffold that combined the excellent biological characteristics of human-like collagen (HLC) and the outstanding mechanical properties of nano-hydroxyapatite (nHA). The scaffolds were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and compression tests, using Relive Registered-Sign Artificial Bone (RAB) scaffolds as a control. HLC/nHA scaffolds displayed homogeneous interconnected macroporous structure and could withstand a compression stress of 2.67 {+-} 0.37 MPa, which was higher than that of the control group. Rabbit chondrocytes were seeded on the composite porous scaffolds and cultured for 21 days. Cell/scaffold constructs were examined using SEM, histological procedures, and biochemical assays for cell proliferation and the production of glycosaminoglycans (GAGs). The results indicated that HLC/nHA porous scaffolds were capable of encouraging cell adhesion, homogeneous distribution and abundant GAG synthesis, and maintaining natural chondrocyte morphology compared to RAB scaffolds. In conclusion, the presented data warrants the further exploration of HLC/nHA scaffolds as a potential biomimetic platform for chondrocytes in cartilage tissue engineering. - Highlights: Black-Right-Pointing-Pointer Human-like collagen was first used to prepare cartilage tissue engineering scaffold. Black-Right-Pointing-Pointer Genipin, a natural biological cross-linking agent, was introduced to treat scaffold. Black-Right-Pointing-Pointer We chose market product as a control.

Systematic Prediction of Scaffold Proteins Reveals New Design Principles in Scaffold-Mediated Signal Transduction

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Hu, Jianfei; Neiswinger, Johnathan; Zhang, Jin; Zhu, Heng; Qian, Jiang

2015-01-01

Scaffold proteins play a crucial role in facilitating signal transduction in eukaryotes by bringing together multiple signaling components. In this study, we performed a systematic analysis of scaffold proteins in signal transduction by integrating protein-protein interaction and kinase-substrate relationship networks. We predicted 212 scaffold proteins that are involved in 605 distinct signaling pathways. The computational prediction was validated using a protein microarray-based approach. The predicted scaffold proteins showed several interesting characteristics, as we expected from the functionality of scaffold proteins. We found that the scaffold proteins are likely to interact with each other, which is consistent with previous finding that scaffold proteins tend to form homodimers and heterodimers. Interestingly, a single scaffold protein can be involved in multiple signaling pathways by interacting with other scaffold protein partners. Furthermore, we propose two possible regulatory mechanisms by which the activity of scaffold proteins is coordinated with their associated pathways through phosphorylation process. PMID:26393507

State Mindfulness During Meditation Predicts Enhanced Cognitive Reappraisal

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Hanley, Adam; Farb, Norman A.; Froeliger, Brett E.

2013-01-01

Putatively, mindfulness meditation involves generation of a state of “nonappraisal”, yet, little is known about how mindfulness may influence appraisal processes. We investigated whether the state and practice of mindfulness could enhance cognitive reappraisal. Participants (N = 44; M age = 24.44, SD = 4.00, range 19 – 38, 82.2% female) were randomized to either 1) mindfulness, 2) suppression, or 3) mind-wandering induction training conditions. Cognitive reappraisal was assessed with the Emotion Regulation Questionnaire (ERQ) prior to experimental induction, and state mindfulness was assessed immediately following induction using the Toronto Mindfulness Scale (TMS). Participants practiced their assigned strategy for one week and then were reassessed with the ERQ reappraisal subscale. Participants receiving mindfulness training reported significantly higher levels of state mindfulness than participants in the thought suppression and mind wandering conditions. Although brief mindfulness training did not lead to significantly greater increases in reappraisal than the other two conditions, state mindfulness during mindfulness meditation was prospectively associated with increases in reappraisal. Path analysis revealed that the indirect effect between mindfulness training and reappraisal was significant through state mindfulness. Degree of state mindfulness achieved during the act of mindfulness meditation significantly predicted increases in reappraisal over time, suggesting that mindfulness may promote emotion regulation by enhancing cognitive reappraisal. PMID:26085851

The Role of Mindfulness to Improve Leadership in Multicultural Context

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Dhevy Puswiartika; Zahrotur Rusyda Hinduan; Marina Sulastiana; Diana Harding

2017-01-01

Mindfulness is present moment awareness with an observing and nonjudging stance. To be mindful means to be fully in the here and now from moment to moment. Mindfulness appears to have broadly positive impacts on human functioning. This review explored the current state of studies regarding mindfulness as a potential psychological construct to improve leadership in multicultural context. Mindfulness associated with higher relationship quality because a mindful leader is better able to be fully...

WiseScaffolder: an algorithm for the semi-automatic scaffolding of Next Generation Sequencing data.

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Farrant, Gregory K; Hoebeke, Mark; Partensky, Frédéric; Andres, Gwendoline; Corre, Erwan; Garczarek, Laurence

2015-09-03

The sequencing depth provided by high-throughput sequencing technologies has allowed a rise in the number of de novo sequenced genomes that could potentially be closed without further sequencing. However, genome scaffolding and closure require costly human supervision that often results in genomes being published as drafts. A number of automatic scaffolders were recently released, which improved the global quality of genomes published in the last few years. Yet, none of them reach the efficiency of manual scaffolding. Here, we present an innovative semi-automatic scaffolder that additionally helps with chimerae resolution and generates valuable contig maps and outputs for manual improvement of the automatic scaffolding. This software was tested on the newly sequenced marine cyanobacterium Synechococcus sp. WH8103 as well as two reference datasets used in previous studies, Rhodobacter sphaeroides and Homo sapiens chromosome 14 (http://gage.cbcb.umd.edu/). The quality of resulting scaffolds was compared to that of three other stand-alone scaffolders: SSPACE, SOPRA and SCARPA. For all three model organisms, WiseScaffolder produced better results than other scaffolders in terms of contiguity statistics (number of genome fragments, N50, LG50, etc.) and, in the case of WH8103, the reliability of the scaffolds was confirmed by whole genome alignment against a closely related reference genome. We also propose an efficient computer-assisted strategy for manual improvement of the scaffolding, using outputs generated by WiseScaffolder, as well as for genome finishing that in our hands led to the circularization of the WH8103 genome. Altogether, WiseScaffolder proved more efficient than three other scaffolders for both prokaryotic and eukaryotic genomes and is thus likely applicable to most genome projects. The scaffolding pipeline described here should be of particular interest to biologists wishing to take advantage of the high added value of complete genomes.

Mindfulness as an Intervention for Recalling Information from a Lecture as a Measure of Academic Performance in Higher Education: A Randomized Experiment

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Bennett, Rebecca Iranzo; Egan, Helen; Cook, Amy; Mantzios, Michail

2018-01-01

Higher education students experience heightened levels of stress and anxiety, and report experiencing negative thoughts and emotions, which influence information retention and recall. In a randomized experiment, we assigned participants to either a mindfulness meditation or an audiobook listening condition, and recorded the information recalled…

PLDLA/PCL-T Scaffold for Meniscus Tissue Engineering.

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Esposito, Andrea Rodrigues; Moda, Marlon; Cattani, Silvia Mara de Melo; de Santana, Gracy Mara; Barbieri, Juliana Abreu; Munhoz, Monique Moron; Cardoso, Túlio Pereira; Barbo, Maria Lourdes Peris; Russo, Teresa; D'Amora, Ugo; Gloria, Antonio; Ambrosio, Luigi; Duek, Eliana Aparecida de Rezende

2013-04-01

The inability of the avascular region of the meniscus to regenerate has led to the use of tissue engineering to treat meniscal injuries. The aim of this study was to evaluate the ability of fibrochondrocytes preseeded on PLDLA/PCL-T [poly(L-co-D,L-lactic acid)/poly(caprolactone-triol)] scaffolds to stimulate regeneration of the whole meniscus. Porous PLDLA/PCL-T (90/10) scaffolds were obtained by solvent casting and particulate leaching. Compressive modulus of 9.5±1.0 MPa and maximum stress of 4.7±0.9 MPa were evaluated. Fibrochondrocytes from rabbit menisci were isolated, seeded directly on the scaffolds, and cultured for 21 days. New Zealand rabbits underwent total meniscectomy, after which implants consisting of cell-free scaffolds or cell-seeded scaffolds were introduced into the medial knee meniscus; the negative control group consisted of rabbits that received no implant. Macroscopic and histological evaluations of the neomeniscus were performed 12 and 24 weeks after implantation. The polymer scaffold implants adapted well to surrounding tissues, without apparent rejection, infection, or chronic inflammatory response. Fibrocartilaginous tissue with mature collagen fibers was observed predominantly in implants with seeded scaffolds compared to cell-free implants after 24 weeks. Similar results were not observed in the control group. Articular cartilage was preserved in the polymeric implants and showed higher chondrocyte cell number than the control group. These findings show that the PLDLA/PCL-T 90/10 scaffold has potential for orthopedic applications since this material allowed the formation of fibrocartilaginous tissue, a structure of crucial importance for repairing injuries to joints, including replacement of the meniscus and the protection of articular cartilage from degeneration.

Dextran hydrogels incorporated with bioactive glass-ceramic: Nanocomposite scaffolds for bone tissue engineering.

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Nikpour, Parisa; Salimi-Kenari, Hamed; Fahimipour, Farahnaz; Rabiee, Sayed Mahmood; Imani, Mohammad; Dashtimoghadam, Erfan; Tayebi, Lobat

2018-06-15

A series of nanocomposite scaffolds comprised of dextran (Dex) and sol-gel derived bioactive glass ceramic nanoparticles (nBGC: 0-16 (wt%)) were fabricated as bioactive scaffolds for bone tissue engineering. Scanning electron microscopy showed Dex/nBGC scaffolds were consisting of a porous 3D microstructure with an average pore size of 240 μm. Energy-dispersive x-ray spectroscopy illustrated nBGC nanoparticles were homogenously distributed within the Dex matrix at low nBGC content (2 wt%), while agglomeration was observed at higher nBGC contents. It was found that the osmotic pressure and nBGC agglomeration at higher nBGC contents leads to increased water uptake, then reduction of the compressive modulus. Bioactivity of Dex/nBGC scaffolds was validated through apatite formation after submersion in the simulated body fluid. Dex/nBGC composite scaffolds were found to show improved human osteoblasts (HOBs) proliferation and alkaline phosphatase (ALP) activity with increasing nBGC content up to 16 (wt%) over two weeks. Owing to favorable physicochemical and bioactivity properties, the Dex/nBGC composite hydrogels can be offered as promising bioactive scaffolds for bone tissue engineering applications. Copyright © 2018 Elsevier Ltd. All rights reserved.

Effects of cell-attachment and extracellular matrix on bone formation in vivo in collagen-hydroxyapatite scaffolds.

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Villa, Max M; Wang, Liping; Rowe, David W; Wei, Mei

2014-01-01

Cell-based tissue engineering can be used to replace missing or damaged bone, but the optimal methods for delivering therapeutic cells to a bony defect have not yet been established. Using transgenic reporter cells as a donor source, two different collagen-hydroxyapatite (HA) scaffolds, and a critical-size calvarial defect model, we investigated the effect of a cell-attachment period prior to implantation, with or without an extracellular matrix-based seeding suspension, on cell engraftment and osteogenesis. When quantitatively compared, the in-house scaffold implanted immediately had a higher mean radiopacity than in-house scaffolds incubated overnight. Both scaffold types implanted immediately had significantly higher area fractions of donor cells, while the in-house collagen-HA scaffolds implanted immediately had higher area fractions of the mineralization label compared with groups incubated overnight. When the cell loading was compared in vitro for each delivery method using the in-house scaffold, immediate loading led to higher numbers of delivered cells. Immediate loading may be preferable in order to ensure robust bone formation in vivo. The use of a secondary ECM carrier improved the distribution of donor cells only when a pre-attachment period was applied. These results have improved our understanding of cell delivery to bony defects in the context of in vivo outcomes.

Reading wild minds: A computational assay of Theory of Mind sophistication across seven primate species.

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Marie Devaine

2017-11-01

Full Text Available Theory of Mind (ToM, i.e. the ability to understand others' mental states, endows humans with highly adaptive social skills such as teaching or deceiving. Candidate evolutionary explanations have been proposed for the unique sophistication of human ToM among primates. For example, the Machiavellian intelligence hypothesis states that the increasing complexity of social networks may have induced a demand for sophisticated ToM. This type of scenario ignores neurocognitive constraints that may eventually be crucial limiting factors for ToM evolution. In contradistinction, the cognitive scaffolding hypothesis asserts that a species' opportunity to develop sophisticated ToM is mostly determined by its general cognitive capacity (on which ToM is scaffolded. However, the actual relationships between ToM sophistication and either brain volume (a proxy for general cognitive capacity or social group size (a proxy for social network complexity are unclear. Here, we let 39 individuals sampled from seven non-human primate species (lemurs, macaques, mangabeys, orangutans, gorillas and chimpanzees engage in simple dyadic games against artificial ToM players (via a familiar human caregiver. Using computational analyses of primates' choice sequences, we found that the probability of exhibiting a ToM-compatible learning style is mainly driven by species' brain volume (rather than by social group size. Moreover, primates' social cognitive sophistication culminates in a precursor form of ToM, which still falls short of human fully-developed ToM abilities.

Biocompatibility of two experimental scaffolds for regenerative endodontics

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Dephne Jack Xin Leong

2016-05-01

Full Text Available Objectives The biocompatibility of two experimental scaffolds for potential use in revascularization or pulp regeneration was evaluated. Materials and Methods One resilient lyophilized collagen scaffold (COLL, releasing metronidazole and clindamycin, was compared to an experimental injectable poly(lactic-co-glycolic acid scaffold (PLGA, releasing clindamycin. Human dental pulp stem cells (hDPSCs were seeded at densities of 1.0 × 104, 2.5 × 104, and 5.0 × 104. The cells were investigated by light microscopy (cell morphology, MTT assay (cell proliferation and a cytokine (IL-8 ELISA test (biocompatibility. Results Under microscope, the morphology of cells coincubated for 7 days with the scaffolds appeared healthy with COLL. Cells in contact with PLGA showed signs of degeneration and apoptosis. MTT assay showed that at 5.0 × 104 hDPSCs, COLL demonstrated significantly higher cell proliferation rates than cells in media only (control, p < 0.01 or cells co-incubated with PLGA (p < 0.01. In ELISA test, no significant differences were observed between cells with media only and COLL at 1, 3, and 6 days. Cells incubated with PLGA expressed significantly higher IL-8 than the control at all time points (p < 0.01 and compared to COLL after 1 and 3 days (p < 0.01. Conclusions The COLL showed superior biocompatibility and thus may be suitable for endodontic regeneration purposes.

Osteoinduction and proliferation of bone-marrow stromal cells in three-dimensional poly (ε-caprolactone)/ hydroxyapatite/collagen scaffolds.

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Wang, Ting; Yang, Xiaoyan; Qi, Xin; Jiang, Chaoyin

2015-05-08

Osteoinduction and proliferation of bone-marrow stromal cells (BMSCs) in three-dimensional (3D) poly(ε-caprolactone) (PCL) scaffolds have not been studied throughly and are technically challenging. This study aimed to optimize nanocomposites of 3D PCL scaffolds to provide superior adhesion, proliferation and differentiation environment for BMSCs in this scenario. BMSCs were isolated and cultured in a novel 3D tissue culture poly(ε-caprolactone) (PCL) scaffold coated with poly-lysine, hydroxyapatite (HAp), collagen and HAp/collagen. Cell morphology was observed and BMSC biomarkers for osteogenesis, osteoblast differentiation and activation were analyzed. Scanning Electron Microscope (SEM) micrographs showed that coating materials were uniformly deposited on the surface of PCL scaffolds and BMSCs grew and aggregated to form clusters during 3D culture. Both mRNA and protein levels of the key players of osteogenesis and osteoblast differentiation and activation, including runt-related transcription factor 2 (Runx2), alkaline phosphates (ALP), osterix, osteocalcin, and RANKL, were significantly higher in BMSCs seeded in PCL scaffolds coated with HAp or HAp/collagen than those seeded in uncoated PCL scaffolds, whereas the expression levels were not significantly different in collagen or poly-lysine coated PCL scaffolds. In addition, poly-lysine, collagen, HAp/collagen, and HAp coated PCL scaffolds had significantly more viable cells than uncoated PCL scaffolds, especially scaffolds with HAp/collagen and collagen-alone coatings. That BMSCs in HAp or HAp/collagen PCL scaffolds had remarkably higher ALP activities than those in collagen-coated alone or uncoated PCL scaffolds indicating higher osteogenic differentiation levels of BMSCs in HAp or HAp/collagen PCL scaffolds. Moreover, morphological changes of BMSCs after four-week of 3D culture confirmed that BMSCs successfully differentiated into osteoblast with spread-out phenotype in HAp/collagen coated PCL scaffolds

Mindful movement and skilled attention

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Clark, Dav; Schumann, Frank; Mostofsky, Stewart H.

2015-01-01

Bodily movement has long been employed as a foundation for cultivating mental skills such as attention, self-control or mindfulness, with recent studies documenting the positive impacts of mindful movement training, such as yoga and tai chi. A parallel “mind-body connection” has also been observed in many developmental disorders. We elaborate a spectrum of mindfulness by considering ADHD, in which deficient motor control correlates with impaired (disinhibited) behavioral control contributing to defining features of excessive distractibility and impulsivity. These data provide evidence for an important axis of variation for wellbeing, in which skillful cognitive control covaries with a capacity for skillful movement. We review empirical and theoretical literature on attention, cognitive control, mind wandering, mindfulness and skill learning, endorsing a model of skilled attention in which motor plans, attention, and executive goals are seen as mutually co-defining aspects of skilled behavior that are linked by reciprocal inhibitory and excitatory connections. Thus, any movement training should engage “higher-order” inhibition and selection and develop a repertoire of rehearsed procedures that coordinate goals, attention and motor plans. However, we propose that mindful movement practice may improve the functional quality of rehearsed procedures, cultivating a transferrable skill of attention. We adopt Langer’s spectrum of mindful learning that spans from “mindlessness” to engagement with the details of the present task and contrast this with the mental attitudes cultivated in standard mindfulness meditation. We particularly follow Feldenkrais’ suggestion that mindful learning of skills for organizing the body in movement might transfer to other forms of mental activity. The results of mindful movement training should be observed in multiple complementary measures, and may have tremendous potential benefit for individuals with ADHD and other

Mindful Movement and Skilled Attention

Directory of Open Access Journals (Sweden)

Dav eClark

2015-06-01

Full Text Available Bodily movement has long been employed as a foundation for cultivating mental skills such as attention, self-control or mindfulness, with recent studies documenting the positive impacts of mindful movement training, such as yoga and tai chi. A parallel mind-body connection has also been observed in many developmental disorders. We elaborate a spectrum of mindfulness by considering ADHD, in which deficient motor control correlates with impaired (disinhibited behavioral control contributing to defining features of excessive distractibility and impulsivity. These data provide evidence for an important axis of variation for wellbeing, in which skillful cognitive control covaries with a capacity for skillful movement. We review empirical and theoretical literature on attention, cognitive control, mind wandering, mindfulness and skill learning, endorsing a model of skilled attention in which motor plans, attention, and executive goals are seen as mutually co-defining aspects of skilled behavior that are linked by reciprocal inhibitory and excitatory connections. Thus, any movement training should engage higher-order inhibition and selection and develop a repertoire of rehearsed procedures that coordinate goals, attention and motor plans. However, we propose that mindful movement practice may improve the functional quality of rehearsed procedures, cultivating a transferrable skill of attention. We adopt Langer’s spectrum of mindful learning that spans from mindlessness to engagement with the details of the present task and contrast this with the mental attitudes cultivated in standard mindfulness meditation. We particularly follow Feldenkrais’ suggestion that mindful learning of skills for organizing the body in movement might transfer to other forms of mental activity. The results of mindful movement training should be observed in multiple complementary measures, and may have tremendous potential benefit for individuals with ADHD and other

PCL-coated hydroxyapatite scaffold derived from cuttlefish bone: In vitro cell culture studies

International Nuclear Information System (INIS)

Milovac, Dajana; Gamboa-Martínez, Tatiana C.; Ivankovic, Marica; Gallego Ferrer, Gloria; Ivankovic, Hrvoje

2014-01-01

In the present study, we examined the potential of using highly porous poly(ε-caprolactone) (PCL)-coated hydroxyapatite (HAp) scaffold derived from cuttlefish bone for bone tissue engineering applications. The cell culture studies were performed in vitro with preosteoblastic MC3T3-E1 cells in static culture conditions. Comparisons were made with uncoated HAp scaffold. The attachment and spreading of preosteoblasts on scaffolds were observed by Live/Dead staining Kit. The cells grown on the HAp/PCL composite scaffold exhibited greater spreading than cells grown on the HAp scaffold. DNA quantification and scanning electron microscopy (SEM) confirmed a good proliferation of cells on the scaffolds. DNA content on the HAp/PCL scaffold was significantly higher compared to porous HAp scaffolds. The amount of collagen synthesis was determined using a hydroxyproline assay. The osteoblastic differentiation of the cells was evaluated by determining alkaline phosphatase (ALP) activity and collagen type I secretion. Furthermore, cell spreading and cell proliferation within scaffolds were observed using a fluorescence microscope. - Highlights: • Hydroxyapatite/poly(ε-caprolactone) scaffold with interconnected pores was prepared • Cytotoxicity test showed that the scaffold was not cytotoxic towards MC3T3-E1 cells • The scaffold supported the attachment, proliferation and differentiation of cells • A 3D cell colonization was confirmed using the fluorescence microscopy • The scaffold might be a promising candidate for bone tissue engineering

PEDOT:PSS-Containing Nanohydroxyapatite/Chitosan Conductive Bionanocomposite Scaffold: Fabrication and Evaluation

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Alireza Lari

2016-01-01

Full Text Available Conductive poly(3,4-ethylenedioxythiophene-poly(4-styrene sulfonate (PEDOT:PSS was incorporated into nanohydroxyapatite/chitosan (nHA/CS composite scaffolds through a freezing and lyophilization technique. The bionanocomposite conductive scaffold was then characterized using several techniques. A scanning electron microscope image showed that the nHA and PEDOT:PSS were dispersed homogeneously in the chitosan matrix, which was also confirmed by energy-dispersive X-ray (EDX analysis. The conductive properties were measured using a digital multimeter. The weight loss and water-uptake properties of the bionanocomposite scaffolds were studied in vitro. An in vitro cell cytotoxicity test was carried out using mouse fibroblast (L929 cells cultured onto the scaffolds. Using a freezing and lyophilization technique, it was possible to fabricate three-dimensional, highly porous, and interconnected PEDOT:PSS/nHA/CS scaffolds with good handling properties. The porosity was 74% and the scaffold’s conductivity was 9.72±0.78 μS. The surface roughness was increased with the incorporation of nHA and PEDOT:PSS into the CS scaffold. The compressive mechanical properties increased significantly with the incorporation of nHA but did not change significantly with the incorporation of PEDOT:PSS. The PEDOT:PSS-containing nHA/CS scaffold exhibited significantly higher cell attachment. The PEDOT:PSS/nHA/CS scaffold could be a potential bionanocomposite conductive scaffold for tissue engineering.

Nerve regeneration using tubular scaffolds from biodegradable polyurethane.

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Hausner, T; Schmidhammer, R; Zandieh, S; Hopf, R; Schultz, A; Gogolewski, S; Hertz, H; Redl, H

2007-01-01

differences. There was a higher level of collagenic connective tissue within the scaffold and within the distal nerve stump. Schwann cells migrated into the polyurethane scaffold. There was no statistical difference to the nerve graft group although Schwann cell counts were lower especially within the middle of the polyurethane scaffold. Axon counts showed a trend-wise decrease within the scaffold. These results suggest that biodegradable polyurethane tubular scaffolds coated with diluted fibrin sealant support peripheral nerve regeneration in a standard gap model in the rat up to 3 months. Three months after surgery no sign of degradation could be seen.

Hybrid Carbon-Based Scaffolds for Applications in Soft Tissue Reconstruction

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Lafdi, Khalid; Joseph, Robert M.; Tsonis, Panagiotis A.

2012-01-01

Current biomedical scaffolds utilized in surgery to repair soft tissues commonly fail to meet the optimal combination of biomechanical and tissue regenerative properties. Carbon is a scaffold alternative that potentially optimizes the balance between mechanical strength, durability, and function as a cell and biologics delivery vehicle that is necessary to restore tissue function while promoting tissue repair. The goals of this study were to investigate the feasibility of fabricating hybrid fibrous carbon scaffolds modified with biopolymer, polycaprolactone and to analyze their mechanical properties and ability to support cell growth and proliferation. Environmental scanning electron microscopy, micro-computed tomography, and cell adhesion and cell proliferation studies were utilized to test scaffold suitability as a cell delivery vehicle. Mechanical properties were tested to examine load failure and elastic modulus. Results were compared to an acellular dermal matrix scaffold control (GraftJacket® [GJ] Matrix), selected for its common use in surgery for the repair of soft tissues. Results indicated that carbon scaffolds exhibited similar mechanical maximums and capacity to support fibroblast adhesion and proliferation in comparison with GJ. Fibroblast adhesion and proliferation was collinear with carbon fiber orientation in regions of sparsely distributed fibers and occurred in clusters in regions of higher fiber density and low porosity. Overall, fibroblast adhesion and proliferation was greatest in lower porosity carbon scaffolds with highly aligned fibers. Stepwise multivariate regression showed that the variability in maximum load of carbon scaffolds and controls were dependent on unique and separate sets of parameters. These finding suggested that there were significant differences in the functional implications of scaffold design and material properties between carbon and dermis derived scaffolds that affect scaffold utility as a tissue replacement

The emotional fundamentals of personality and the higher affective polarities of mind. Comment on "Personality from a cognitive-biological perspective" by Y. Neuman

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Panksepp, Jaak; Davis, Ken

2014-12-01

In brain-based personality theory, two things seem certain: i) the evolved functional organization of our subcortical affective mind, and ii) the diverse potentials for developmental programming of our high cognitive minds (i.e., our initially empty - tabula rasa like - neocortical spaces are largely developmentally programed to manifest higher mental abilities). In considering these two global aspects of brain-mind functions, we can be confident that primal subcortical functions (e.g., the capacity for raw emotions/affects, evident in all vertebrate species) evolved. Indeed, ancient creatures such as lamprey eels, with whom we shared ancestry 560 million years ago, still posses most neural systems that are homologous to those that constitute our own primal affective capacities [1]. Considering that primal emotional affects arise from such systems, there appears to be some remarkable continuity in our primal mental origins. The neural foundations of human emotional feelings, long neglected by academic psychology (for lack of empirical accessibility), may contain the rudimentary neuro-affective substrates of personality [2].

Magnetic responsive hydroxyapatite composite scaffolds construction for bone defect reparation

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Zeng XB

2012-07-01

Full Text Available Xiao Bo Zeng, Hao Hu, Li Qin Xie, Fang Lan, Wen Jiang, Yao Wu, Zhong Wei GuNational Engineering Research Center for Biomaterials, Sichuan University, Chengdu, Sichuan, People's Republic of ChinaIntroduction: In recent years, interest in magnetic biomimetic scaffolds for tissue engineering has increased considerably. A type of magnetic scaffold composed of magnetic nanoparticles (MNPs and hydroxyapatite (HA for bone repair has been developed by our research group.Aim and methods: In this study, to investigate the influence of the MNP content (in the scaffolds on the cell behaviors and the interactions between the magnetic scaffold and the exterior magnetic field, a series of MNP-HA magnetic scaffolds with different MNP contents (from 0.2% to 2% were fabricated by immersing HA scaffold into MNP colloid. ROS 17/2.8 and MC3T3-E1 cells were cultured on the scaffolds in vitro, with and without an exterior magnetic field, respectively. The cell adhesion, proliferation and differentiation were evaluated via scanning electron microscopy; confocal laser scanning microscopy; and 3-(4,5-Dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT, alkaline phosphatase, and bone gla protein activity tests.Results: The results demonstrated the positive influence of the magnetic scaffolds on cell adhesion, proliferation, and differentiation. Further, a higher amount of MNPs on the magnetic scaffolds led to more significant stimulation.Conclusion: The magnetic scaffold can respond to the exterior magnetic field and engender some synergistic effect to intensify the stimulating effect of a magnetic field to the proliferation and differentiation of cells.Keywords: magnetic therapy, magnetic nanoparticles, bone repair, magnetic responsive

Scaffolding as an effort for thinking process optimization on heredity

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Azizah, N. R.; Masykuri, M.; Prayitno, B. A.

2018-04-01

Thinking is an activity and process of manipulating and transforming data or information into memory. Thinking process is different between one and other person. Thinking process can be developed by interaction between student and their environment, such as scaffolding. Given scaffolding is based on each student necessity. There are 2 level on scaffolding such as explaining, reviewing, and restructuring; and developing conceptual thinking. This research is aimed to describe student’s thinking process on heredity especially on inheritance that is before and after scaffolding. This research used descriptive qualitative method. There were three kinds of subject degree such as the students with high, middle, and low achieving students. The result showed that subjects had some difficulty in dihybrid inheritance question in different place. Most difficulty was on determining the number of different characteristic, parental genotype, gamete, and ratio of genotype and phenotype F2. Based on discussed during scaffolding showed that the subjects have some misunderstanding terms and difficulty to determine parental, gamete, genotype, and phenotype. Final result in this research showed that the subjects develop thinking process higher after scaffolding. Therefore the subjects can solve question properly.

Predicting permeability of regular tissue engineering scaffolds: scaling analysis of pore architecture, scaffold length, and fluid flow rate effects.

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Rahbari, A; Montazerian, H; Davoodi, E; Homayoonfar, S

2017-02-01

The main aim of this research is to numerically obtain the permeability coefficient in the cylindrical scaffolds. For this purpose, a mathematical analysis was performed to derive an equation for desired porosity in terms of morphological parameters. Then, the considered cylindrical geometries were modeled and the permeability coefficient was calculated according to the velocity and pressure drop values based on the Darcy's law. In order to validate the accuracy of the present numerical solution, the obtained permeability coefficient was compared with the published experimental data. It was observed that this model can predict permeability with the utmost accuracy. Then, the effect of geometrical parameters including porosity, scaffold pore structure, unit cell size, and length of the scaffolds as well as entrance mass flow rate on the permeability of porous structures was studied. Furthermore, a parametric study with scaling laws analysis of sample length and mass flow rate effects on the permeability showed good fit to the obtained data. It can be concluded that the sensitivity of permeability is more noticeable at higher porosities. The present approach can be used to characterize and optimize the scaffold microstructure due to the necessity of cell growth and transferring considerations.

Mindfulness predicts student nurses' communication self-efficacy: A cross-national comparative study.

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Sundling, Vibeke; Sundler, Annelie J; Holmström, Inger K; Kristensen, Dorte Vesterager; Eide, Hilde

2017-08-01

The aim of this study was to compare student nurses' communication self-efficacy, empathy, and mindfulness across two countries, and to analyse the relationship between these qualities. The study had a cross-sectional design. Data was collected from final year student nurses in Norway and Sweden. Communication self-efficacy, empathy, and mindfulness were reported by questionnaires; Clear-cut communication with patients, Jefferson Scale of Empathy, and Langer 14 items mindfulness scale. The study included 156 student nurses, 94 (60%) were Swedish. The mean communication self-efficacy score was 119 (95% CI 116-122), empathy score 115 (95% CI 113-117) and mindfulness score 79 (95% CI 78-81). A Mann-Whitney test showed that Swedish students scored significantly higher on communication self-efficacy, empathy, and mindfulness than Norwegian students did. When adjusted for age, gender, and country in a multiple linear regression, mindfulness was the only independent predictor of communication self-efficacy. The Swedish student nurses in this study scored higher on communication self-efficacy, empathy, and mindfulness than Norwegian students did. Student nurses scoring high on mindfulness rated their communication self-efficacy higher. A mindful learning approach may improve communication self-efficacy and possibly the effect of communication skills training. Copyright © 2017 Elsevier B.V. All rights reserved.

The protective effects of brief mindfulness meditation training.

Science.gov (United States)

Banks, Jonathan B; Welhaf, Matthew S; Srour, Alexandra

2015-05-01

Mindfulness meditation has gained a great deal of attention in recent years due to the variety of physical and psychological benefits, including improved working memory, decreased mind wandering and reduced impact of stress on working memory. The current study examined a 1-week at home mindfulness meditation intervention compared to an active control intervention. Results suggest that mindfulness meditation does not increase working memory or decrease mind wandering but does prevent stress related working memory impairments. Mindfulness meditation appears to alter the factors that impair working memory such that the negative impact of mind wandering on working memory was only evident at higher levels of negative affect. The use of cognitive mechanism words in narratives of stressful events did not differ by condition but predicted poorer working memory in the control condition. The results support the use of an at home mindfulness meditation intervention for reducing stress-related impairments. Copyright © 2015 Elsevier Inc. All rights reserved.

Mind full of life: Does mindfulness confer resilience to suicide by increasing zest for life?

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Collins, Khan R L; Stritzke, Werner G K; Page, Andrew C; Brown, Julia D; Wylde, Tricia J

2018-01-15

Mindfulness is a trainable skill that may enhance resilience to suicidality among vulnerable groups such as young people. The current study examined whether mindfulness protects against suicidal desire in the face of heightened risk and adversity by increasing zest for life in a sample of university students. In a prospective design, participants (N = 233) were assessed at two time points over eight weeks. Online surveys included the Mindful Attention and Awareness Scale, Zest for Life Scale, Interpersonal Needs Questionnaire, Kessler Psychological Distress Scale, and items assessing suicidal ideation and suicidal intent. Baseline mindfulness was associated with lower suicidal ideation and intent at follow-up. Moderated mediation analyses confirmed the effects of mindfulness on ideation and intent were mediated by zest for life and these indirect effects were stronger at higher versus lower levels of general (psychological distress) and suicide-specific (perceived burdensomeness and thwarted belongingness) risk. Single item assessments of suicidal desire. Findings suggest that mindfulness protects against suicidal desire in conditions of heightened risk and adversity by enhancing one's orientation towards a life worth living. Theories of suicide should consider the dynamic interplay between risk and life-sustaining resilience, while clinicians treating suicidality could use mindfulness strategies to strengthen the desire to (re)engage with life, thereby complementing direct amelioration of suicide risk factors. Copyright © 2017 Elsevier B.V. All rights reserved.

Mindfulness Interventions.

Science.gov (United States)

Creswell, J David

2017-01-03

Mindfulness interventions aim to foster greater attention to and awareness of present moment experience. There has been a dramatic increase in randomized controlled trials (RCTs) of mindfulness interventions over the past two decades. This article evaluates the growing evidence of mindfulness intervention RCTs by reviewing and discussing (a) the effects of mindfulness interventions on health, cognitive, affective, and interpersonal outcomes; (b) evidence-based applications of mindfulness interventions to new settings and populations (e.g., the workplace, military, schools); (c) psychological and neurobiological mechanisms of mindfulness interventions; (d) mindfulness intervention dosing considerations; and (e) potential risks of mindfulness interventions. Methodologically rigorous RCTs have demonstrated that mindfulness interventions improve outcomes in multiple domains (e.g., chronic pain, depression relapse, addiction). Discussion focuses on opportunities and challenges for mindfulness intervention research and on community applications.

Computational physics of the mind

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Duch, Włodzisław

1996-08-01

In the XIX century and earlier physicists such as Newton, Mayer, Hooke, Helmholtz and Mach were actively engaged in the research on psychophysics, trying to relate psychological sensations to intensities of physical stimuli. Computational physics allows to simulate complex neural processes giving a chance to answer not only the original psychophysical questions but also to create models of the mind. In this paper several approaches relevant to modeling of the mind are outlined. Since direct modeling of the brain functions is rather limited due to the complexity of such models a number of approximations is introduced. The path from the brain, or computational neurosciences, to the mind, or cognitive sciences, is sketched, with emphasis on higher cognitive functions such as memory and consciousness. No fundamental problems in understanding of the mind seem to arise. From a computational point of view realistic models require massively parallel architectures.

Membrane-reinforced three-dimensional electrospun silk fibroin scaffolds for bone tissue engineering

International Nuclear Information System (INIS)

Yang, Sung Yeun; Hwang, Tae Heon; Ryu, WonHyoung; Che, Lihua; Oh, Jin Soo; Ha, Yoon

2015-01-01

Electrospun silk fibroin (SF) scaffolds have drawn much attention because of their resemblance to natural tissue architecture such as extracellular matrix, and the biocompatibility of SF as a candidate material to replace collagen. However, electrospun scaffolds lack the physical integrity of bone tissue scaffolds, which require resistance to mechanical loadings. In this work, we propose membrane-reinforced electrospun SF scaffolds by a serial process of electrospinning and freeze-drying of SF solutions in two different solvents: formic acid and water, respectively. After wet electrospinning followed by replacement of methanol with water, SF nanofibers dispersed in water were mixed with aqueous SF solution. Freeze-drying of the mixed solution resulted in 3D membrane-connected SF nanofibrous scaffolds (SF scaffolds) with a thickness of a few centimeters. We demonstrated that the SF concentration of aqueous SF solution controlled the degree of membrane reinforcement between nanofibers. It was also shown that both increase in degree of membrane reinforcement and inclusion of hydroxyapatite (HAP) nanoparticles resulted in higher resistance to compressive loadings of the SF scaffolds. Culture of human osteoblasts on collagen, SF, and SF-HAP scaffolds showed that both SF and SF-HAP scaffolds had biocompatibility and cell proliferation superior to that of the collagen scaffolds. SF-HAP scaffolds with and without BMP-2 were used for in vivo studies for 4 and 8 weeks, and they showed enhanced bone tissue formation in rat calvarial defect models. (paper)

Citation patterns and trends of systematic reviews about mindfulness.

Science.gov (United States)

Chiesa, Alberto; Fazia, Teresa; Bernardinelli, Luisa; Morandi, Gabriella

2017-08-01

We performed a citation analysis of the literature about mindfulness aimed at describing the most significant topics and the impact of more relevant papers. We classified 128 systematic reviews about mindfulness-based intervention retrieved in Scopus according to their object, the population included and the type of mindfulness proposed. The citation counting was reported. The cumulative citation numbers per chronological years and article life were analyzed thorough a linear regression model. 1) We observed a general increase in the number of reviews published from 2003 to 2016; 2) two reviews collected the 33% of the overall citations; 3) citation counting for clinical and mixed population collected the 90% of total citations; 4) clinical reviews had higher cumulative citation per publication/year growth. As mindfulness research advances, higher attention should be given to the mechanisms by which mindfulness interventions work so as to provide fruitful insights for future research. Copyright © 2017 Elsevier Ltd. All rights reserved.

Ceramic Identity Contributes to Mechanical Properties and Osteoblast Behavior on Macroporous Composite Scaffolds

Directory of Open Access Journals (Sweden)

J. Kent Leach

2012-05-01

Full Text Available Implants formed of metals, bioceramics, or polymers may provide an alternative to autografts for treating large bone defects. However, limitations to each material motivate the examination of composites to capitalize on the beneficial aspects of individual components and to address the need for conferring bioactive behavior to the polymer matrix. We hypothesized that the inclusion of different bioceramics in a ceramic-polymer composite would alter the physical properties of the implant and the cellular osteogenic response. To test this, composite scaffolds formed from poly(lactide-co-glycolide (PLG and either hydroxyapatite (HA, β-tricalcium phosphate (TCP, or bioactive glass (Bioglass 45S^®, BG were fabricated, and the physical properties of each scaffold were examined. We quantified cell proliferation by DNA content, osteogenic response of human osteoblasts (NHOsts to composite scaffolds by alkaline phosphatase (ALP activity, and changes in gene expression by qPCR. Compared to BG-PLG scaffolds, HA-PLG and TCP-PLG composite scaffolds possessed greater compressive moduli. NHOsts on BG-PLG substrates exhibited higher ALP activity than those on control, HA-, or TCP-PLG scaffolds after 21 days, and cells on composites exhibited a 3-fold increase in ALP activity between 7 and 21 days versus a minimal increase on control scaffolds. Compared to cells on PLG controls, RUNX2 expression in NHOsts on composite scaffolds was lower at both 7 and 21 days, while expression of genes encoding for bone matrix proteins (COL1A1 and SPARC was higher on BG-PLG scaffolds at both time points. These data demonstrate the importance of selecting a ceramic when fabricating composites applied for bone healing.

Metaphilosophy of Mind: how Do Minds Investigate Minds? Refutation of the Theocentric View

OpenAIRE

Werner, Konrad

2016-01-01

I shall propose metaphilosophy of mind as the philosophy of mind investigating mind. That is to say, I pose the question of how knowledge of mind provided by cognitive science, broadly construed, is constrained by the epistemic position of the knower, i.e. by the very fact that it is undertaken by a mind. Here I would like to propose a minimal framework, based on two distinctions: (i) the standard one between empirical and conceptual analysis; (ii) a new one, between the internal questions of...

Comparison between PCL/hydroxyapatite (HA) and PCL/halloysite nanotube (HNT) composite scaffolds prepared by co-extrusion and gas foaming.

Science.gov (United States)

Jing, Xin; Mi, Hao-Yang; Turng, Lih-Sheng

2017-03-01

In this work, three-dimensional poly(caprolactone) (PCL) tissue engineering scaffolds were prepared by co-extrusion and gas foaming. Biocompatible hydroxyapatite (HA) and halloysite nanotubes (HNT) were added to the polymer matrix to enhance the mechanical properties and bioactivity of the composite scaffolds. The effects of HA and HNT on the rheological behavior, microstructure, and mechanical properties of the composite scaffolds were systematically compared. It was found that the HNT improved viscosity more significantly than HA, and reduced the pore size of scaffolds, while the mechanical performance of PCL/HNT scaffolds was higher than PCL/HA scaffolds with the same filler content. Human mesenchymal stem cells (hMSCs) were used as the cell model to compare the biological properties of two composite scaffolds. The results demonstrated that cells could survive on all scaffolds, and showed a more flourishing living state on the composite scaffolds. The cell differentiation for 5% HA and 1% HNT scaffolds were significantly higher than other scaffolds, while the differentiation of 5% HNT scaffolds was lower than that of 1% HNT scaffolds mainly because of the reduced pore size and pore interconnectivity. Therefore, this study suggested that, with proper filler content and control of microstructure through processing, HNT could be a suitable substitute for HA for bone tissue engineering to reduce the cost and improve mechanical performance. Copyright © 2016. Published by Elsevier B.V.

The pro-angiogenic properties of multi-functional bioactive glass composite scaffolds

KAUST Repository

Gerhardt, Lutz Christian; Widdows, Kate L.; Erol, Melek M.; Burch, Charles W.; Sanz-Herrera, José A.; Ochoa, Ignacio; Stä mpfli, Rolf; Roqan, Iman S.; Gabe, Simon M.; Ansari, Tahera I.; Boccaccini, Aldo R.

2011-01-01

The angiogenic properties of micron-sized (m-BG) and nano-sized (n-BG) bioactive glass (BG) filled poly(D,L lactide) (PDLLA) composites were investigated. On the basis of cell culture work investigating the secretion of vascular endothelial growth factor (VEGF) by human fibroblasts in contact with composite films (0, 5, 10, 20 wt %), porous 3D composite scaffolds, optimised with respect to the BG filler content capable of inducing angiogenic response, were produced. The in vivo vascularisation of the scaffolds was studied in a rat animal model and quantified using stereological analyses. The prepared scaffolds had high porosities (81-93%), permeability (k = 5.4-8.6 × 10-9 m2) and compressive strength values (0.4-1.6 MPa) all in the range of trabecular bone. On composite films containing 20 wt % m-BG or n-BG, human fibroblasts produced 5 times higher VEGF than on pure PDLLA films. After 8 weeks of implantation, m-BG and n-BG containing scaffolds were well-infiltrated with newly formed tissue and demonstrated higher vascularisation and percentage blood vessel to tissue (11.6-15.1%) than PDLLA scaffolds (8.5%). This work thus shows potential for the regeneration of hard-soft tissue defects and increased bone formation arising from enhanced vascularisation of the construct. © 2011 Elsevier Ltd.

The pro-angiogenic properties of multi-functional bioactive glass composite scaffolds

KAUST Repository

Gerhardt, Lutz Christian

2011-06-01

The angiogenic properties of micron-sized (m-BG) and nano-sized (n-BG) bioactive glass (BG) filled poly(D,L lactide) (PDLLA) composites were investigated. On the basis of cell culture work investigating the secretion of vascular endothelial growth factor (VEGF) by human fibroblasts in contact with composite films (0, 5, 10, 20 wt %), porous 3D composite scaffolds, optimised with respect to the BG filler content capable of inducing angiogenic response, were produced. The in vivo vascularisation of the scaffolds was studied in a rat animal model and quantified using stereological analyses. The prepared scaffolds had high porosities (81-93%), permeability (k = 5.4-8.6 × 10-9 m2) and compressive strength values (0.4-1.6 MPa) all in the range of trabecular bone. On composite films containing 20 wt % m-BG or n-BG, human fibroblasts produced 5 times higher VEGF than on pure PDLLA films. After 8 weeks of implantation, m-BG and n-BG containing scaffolds were well-infiltrated with newly formed tissue and demonstrated higher vascularisation and percentage blood vessel to tissue (11.6-15.1%) than PDLLA scaffolds (8.5%). This work thus shows potential for the regeneration of hard-soft tissue defects and increased bone formation arising from enhanced vascularisation of the construct. © 2011 Elsevier Ltd.

Scaffolded biology.

Science.gov (United States)

Minelli, Alessandro

2016-09-01

Descriptions and interpretations of the natural world are dominated by dichotomies such as organism vs. environment, nature vs. nurture, genetic vs. epigenetic, but in the last couple of decades strong dissatisfaction with those partitions has been repeatedly voiced and a number of alternative perspectives have been suggested, from perspectives such as Dawkins' extended phenotype, Turner's extended organism, Oyama's Developmental Systems Theory and Odling-Smee's niche construction theory. Last in time is the description of biological phenomena in terms of hybrids between an organism (scaffolded system) and a living or non-living scaffold, forming unit systems to study processes such as reproduction and development. As scaffold, eventually, we can define any resource used by the biological system, especially in development and reproduction, without incorporating it as happens in the case of resources fueling metabolism. Addressing biological systems as functionally scaffolded systems may help pointing to functional relationships that can impart temporal marking to the developmental process and thus explain its irreversibility; revisiting the boundary between development and metabolism and also regeneration phenomena, by suggesting a conceptual framework within which to investigate phenomena of regular hypermorphic regeneration such as characteristic of deer antlers; fixing a periodization of development in terms of the times at which a scaffolding relationship begins or is terminated; and promoting plant galls to legitimate study objects of developmental biology.

The distracted mind on the wheel: Overall propensity to mind wandering is associated with road crash responsibility.

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Gil-Jardiné, Cédric; Née, Mélanie; Lagarde, Emmanuel; Schooler, Jonathan; Contrand, Benjamin; Orriols, Ludivine; Galera, Cédric

2017-01-01

The role of distractions on attentional lapses that place road users in higher risk of crash remains poorly understood. We aimed to assess the respective impact of (i) mind wandering trait (propensity to mind wander in the everyday life as measured with a set of 4 questions on the proportion of time spent mind wandering in 4 different situations) and (ii) mind wandering state (disturbing thoughts just before the crash) on road crash risk using a comparison between responsible and non-responsible drivers. 954 drivers injured in a road crash were interviewed at the adult emergency department of the Bordeaux university hospital in France (2013-2015). Responsibility for the crash, mind wandering (trait/state), external distraction, alcohol use, psychotropic drug use, and sleep deprivation were evaluated. Based on questionnaire reports, 39% of respondents were classified with a mind wandering trait and 13% reported a disturbing thought just before the crash. While strongly correlated, mind wandering state and trait were independently associated with responsibility for a traffic crash (State: OR = 2.51, 95% CI: 1.64-3.83 and Trait: OR = 1.62, 95% CI: 1.22-2.16 respectively). Self-report of distracting thoughts therefore did not capture the entire risk associated with the propensity of the mind to wander, either because of under-reported thoughts and/or other deleterious mechanisms to be further explored.

The distracted mind on the wheel: Overall propensity to mind wandering is associated with road crash responsibility.

Directory of Open Access Journals (Sweden)

Cédric Gil-Jardiné

Full Text Available The role of distractions on attentional lapses that place road users in higher risk of crash remains poorly understood. We aimed to assess the respective impact of (i mind wandering trait (propensity to mind wander in the everyday life as measured with a set of 4 questions on the proportion of time spent mind wandering in 4 different situations and (ii mind wandering state (disturbing thoughts just before the crash on road crash risk using a comparison between responsible and non-responsible drivers. 954 drivers injured in a road crash were interviewed at the adult emergency department of the Bordeaux university hospital in France (2013-2015. Responsibility for the crash, mind wandering (trait/state, external distraction, alcohol use, psychotropic drug use, and sleep deprivation were evaluated. Based on questionnaire reports, 39% of respondents were classified with a mind wandering trait and 13% reported a disturbing thought just before the crash. While strongly correlated, mind wandering state and trait were independently associated with responsibility for a traffic crash (State: OR = 2.51, 95% CI: 1.64-3.83 and Trait: OR = 1.62, 95% CI: 1.22-2.16 respectively. Self-report of distracting thoughts therefore did not capture the entire risk associated with the propensity of the mind to wander, either because of under-reported thoughts and/or other deleterious mechanisms to be further explored.

Mindfulness in Salah Prayer and its Association with Mental Health.

Science.gov (United States)

Ijaz, Shahid; Khalily, Muhammad Tahir; Ahmad, Irshad

2017-12-01

Plethora of researches has been carried out for the last many decades and has identified relationship between mental health and religious convictions; in particular, range of religious practices has been found instrumental in the promotion of mental health. The aim of this paper is to find out association between mindfulness in Salah (prayer) and mental health of individuals who identify themselves with Islam and to examine the mental health of those Muslims who offer Salah prayer with mindfulness and those who offer without mindfulness. A total of 174 participants with mean age of 21.57 including 62% males and females 38% were selected through convenient sampling. RAND Mental Health Inventory was used to measure mental health and other three variables; three self-reported measures were constructed. They included Islamic religious education scale, Salah education scale and mindfulness in Salah scale. Psychometric properties for all scales were established. The findings indicated that mean on mindfulness and mental health was significantly higher for those who were offering Salah (prayer) regularly (p prayer) with mindfulness had also significantly higher mean for mental health (p prayer regularly and with mindfulness have better mental health as compared with those who don't offer it regularly and with mindfulness. The findings of this study urge to spread awareness regarding offering prayer regularly with mindfulness for the better outcome of mental health in people.

Continuous cellularization of calcium phosphate hybrid scaffolds induced by plasma polymer activation

Energy Technology Data Exchange (ETDEWEB)

Bergemann, Claudia [University Medical Center Rostock, Cell Biology, Schillingallee 69, D-18057 Rostock (Germany); Cornelsen, Matthias [University of Rostock, Fluid Technology and Microfluidics, Justus-von-Liebig Weg 6, D-18059 Rostock (Germany); Quade, Antje [Leibniz-Institute for Plasma Science and Technology (INP), Felix-Hausdorff-Str. 2, D-17489 Greifswald (Germany); Laube, Thorsten; Schnabelrauch, Matthias [INNOVENT e.V., Biomaterials Department, Pruessingstrasse 27B, D-07745 Jena (Germany); Rebl, Henrike [University Medical Center Rostock, Cell Biology, Schillingallee 69, D-18057 Rostock (Germany); Weißmann, Volker [Institute for Polymer Technologies (IPT) e.V., Alter Holzhafen 19, D-23966 Wismar (Germany); Seitz, Hermann [University of Rostock, Fluid Technology and Microfluidics, Justus-von-Liebig Weg 6, D-18059 Rostock (Germany); Nebe, Barbara, E-mail: barbara.nebe@med.uni-rostock.de [University Medical Center Rostock, Cell Biology, Schillingallee 69, D-18057 Rostock (Germany)

2016-02-01

The generation of hybrid materials based on β-tricalcium phosphate (TCP) and various biodegradable polymers like poly(L-lactide-co-D,L-lactide) (PLA) represents a common approach to overcoming the disadvantages of pure TCP devices. These disadvantages lie in TCP's mechanical properties, such as brittleness. The positive characteristic of PLA — improvement of compressive strength of calcium phosphate scaffolds – is diametrically opposed to its cell attractiveness. Therefore, the objective of this work was to optimize osteoblast migration and cellularization inside a three-dimensionally (3D) printed, PLA polymer stabilized TCP hybrid scaffold by a plasma polymer process depositing amino groups via allylamine. MG-63 osteoblastic cells inside the 10 mm hybrid scaffold were dynamically cultivated for 14 days in a 3D model system integrated in a perfusion reactor. The whole TCP/PLA hybrid scaffold was continuously colonized due to plasma polymerized allylamine activation inducing the migration potential of osteoblasts. - Highlights: • Mechanical stabilization of β-tricalcium phosphate scaffolds by PLA infiltration • Hybrid scaffolds with higher cell attraction due to plasma polymerized allylamine • 3D perfusion in vitro model for observation of cell migration inside scaffolds • Enhanced cell migration within plasma polymer coated TCP hybrid scaffolds.

Continuous cellularization of calcium phosphate hybrid scaffolds induced by plasma polymer activation

International Nuclear Information System (INIS)

Bergemann, Claudia; Cornelsen, Matthias; Quade, Antje; Laube, Thorsten; Schnabelrauch, Matthias; Rebl, Henrike; Weißmann, Volker; Seitz, Hermann; Nebe, Barbara

2016-01-01

The generation of hybrid materials based on β-tricalcium phosphate (TCP) and various biodegradable polymers like poly(L-lactide-co-D,L-lactide) (PLA) represents a common approach to overcoming the disadvantages of pure TCP devices. These disadvantages lie in TCP's mechanical properties, such as brittleness. The positive characteristic of PLA — improvement of compressive strength of calcium phosphate scaffolds – is diametrically opposed to its cell attractiveness. Therefore, the objective of this work was to optimize osteoblast migration and cellularization inside a three-dimensionally (3D) printed, PLA polymer stabilized TCP hybrid scaffold by a plasma polymer process depositing amino groups via allylamine. MG-63 osteoblastic cells inside the 10 mm hybrid scaffold were dynamically cultivated for 14 days in a 3D model system integrated in a perfusion reactor. The whole TCP/PLA hybrid scaffold was continuously colonized due to plasma polymerized allylamine activation inducing the migration potential of osteoblasts. - Highlights: • Mechanical stabilization of β-tricalcium phosphate scaffolds by PLA infiltration • Hybrid scaffolds with higher cell attraction due to plasma polymerized allylamine • 3D perfusion in vitro model for observation of cell migration inside scaffolds • Enhanced cell migration within plasma polymer coated TCP hybrid scaffolds

Mind-body interventions during pregnancy.

Science.gov (United States)

Beddoe, Amy E; Lee, Kathryn A

2008-01-01

To examine published evidence on the effectiveness of mind-body interventions during pregnancy on perceived stress, mood, and perinatal outcomes. Computerized searches of PubMed, Cinahl, PsycINFO, and the Cochrane Library. Twelve out of 64 published intervention studies between 1980 and February 2007 of healthy, adult pregnant women met criteria for review. Studies were categorized by type of mind-body modality used. Progressive muscle relaxation was the most common intervention. Other studies used a multimodal psychoeducation approach or a yoga and meditation intervention. The research contained methodological problems, primarily absence of a randomized control group or failure to adequately control confounding variables. Nonetheless, there was modest evidence for the efficacy of mind-body modalities during pregnancy. Treatment group outcomes included higher birthweight, shorter length of labor, fewer instrument-assisted births, and reduced perceived stress and anxiety. There is evidence that pregnant women have health benefits from mind-body therapies used in conjunction with conventional prenatal care. Further research is necessary to build on these studies in order to predict characteristics of subgroups that might benefit from mind-body practices and examine cost effectiveness of these interventions on perinatal outcomes.

Mindfulness Interventions in Physical Rehabilitation: A Scoping Review.

Science.gov (United States)

Hardison, Mark E; Roll, Shawn C

2016-01-01

A scoping review was conducted to describe how mindfulness is used in physical rehabilitation, identify implications for occupational therapy practice, and guide future research on clinical mindfulness interventions. A systematic search of four literature databases produced 1,524 original abstracts, of which 16 articles were included. Although only 3 Level I or II studies were identified, the literature included suggests that mindfulness interventions are helpful for patients with musculoskeletal and chronic pain disorders and demonstrate trends toward outcome improvements for patients with neurocognitive and neuromotor disorders. Only 2 studies included an occupational therapist as the primary mindfulness provider, but all mindfulness interventions in the selected studies fit within the occupational therapy scope of practice according to the American Occupational Therapy Association's Occupational Therapy Practice Framework: Domain and Process. Higher-level research is needed to evaluate the effects of mindfulness interventions in physical rehabilitation and to determine best practices for the use of mindfulness by occupational therapy practitioners. Copyright © 2016 by the American Occupational Therapy Association, Inc.

The effect of scaffold pore size in cartilage tissue engineering.

Science.gov (United States)

Nava, Michele M; Draghi, Lorenza; Giordano, Carmen; Pietrabissa, Riccardo

2016-07-26

The effect of scaffold pore size and interconnectivity is undoubtedly a crucial factor for most tissue engineering applications. The aim of this study was to examine the effect of pore size and porosity on cartilage construct development in different scaffolds seeded with articular chondrocytes. We fabricated poly-L-lactide-co-trimethylene carbonate scaffolds with different pore sizes, using a solvent-casting/particulate-leaching technique. We seeded primary bovine articular chondrocytes on these scaffolds, cultured the constructs for 2 weeks and examined cell proliferation, viability and cell-specific production of cartilaginous extracellular matrix proteins, including GAG and collagen. Cell density significantly increased up to 50% with scaffold pore size and porosity, likely facilitated by cell spreading on the internal surface of bigger pores, and by increased mass transport of gases and nutrients to cells, and catabolite removal from cells, allowed by lower diffusion barriers in scaffolds with a higher porosity. However, both the cell metabolic activity and the synthesis of cartilaginous matrix proteins significantly decreased by up to 40% with pore size. We propose that the association of smaller pore diameters, causing 3-dimensional cell aggregation, to a lower oxygenation caused by a lower porosity, could have been the condition that increased the cell-specific synthesis of cartilaginous matrix proteins in the scaffold with the smallest pores and the lowest porosity among those tested. In the initial steps of in vitro cartilage engineering, the combination of small scaffold pores and low porosity is an effective strategy with regard to the promotion of chondrogenesis.

Mechanoactive scaffold induces tendon remodeling and expression of fibrocartilage markers.

Science.gov (United States)

Spalazzi, Jeffrey P; Vyner, Moira C; Jacobs, Matthew T; Moffat, Kristen L; Lu, Helen H

2008-08-01

Biological fixation of soft tissue-based grafts for anterior cruciate ligament (ACL) reconstruction poses a major clinical challenge. The ACL integrates with subchondral bone through a fibrocartilage enthesis, which serves to minimize stress concentrations and enables load transfer between two distinct tissue types. Functional integration thus requires the reestablishment of this fibrocartilage interface on reconstructed ACL grafts. We designed and characterized a novel mechanoactive scaffold based on a composite of poly-alpha-hydroxyester nanofibers and sintered microspheres; we then used the scaffold to test the hypothesis that scaffold-induced compression of tendon grafts would result in matrix remodeling and the expression of fibrocartilage interface-related markers. Histology coupled with confocal microscopy and biochemical assays were used to evaluate the effects of scaffold-induced compression on tendon matrix collagen distribution, cellularity, proteoglycan content, and gene expression over a 2-week period. Scaffold contraction resulted in over 15% compression of the patellar tendon graft and upregulated the expression of fibrocartilage-related markers such as Type II collagen, aggrecan, and transforming growth factor-beta3 (TGF-beta3). Additionally, proteoglycan content was higher in the compressed tendon group after 1 day. The data suggest the potential of a mechanoactive scaffold to promote the formation of an anatomic fibrocartilage enthesis on tendon-based ACL reconstruction grafts.

Comparison of three-dimensional printing and vacuum freeze-dried techniques for fabricating composite scaffolds

Energy Technology Data Exchange (ETDEWEB)

Sun, Kai [Tianjin First Center Hospital, No. 24 Fukang Road, Tianjin, TJ 300192 (China); Li, Ruixin [Institute of Medical Equipment, Academy of Military and Medical Sciences, No. 106, Wandong Street, Hedong District, Tianjin 300000 (China); Jiang, Wenxue, E-mail: jiangortholivea@sina.cn [Tianjin First Center Hospital, No. 24 Fukang Road, Tianjin, TJ 300192 (China); Sun, Yufu [Tianjin First Center Hospital, No. 24 Fukang Road, Tianjin, TJ 300192 (China); Li, Hui [Tianjin Medical University General Hospital, No. 154 Anshan Road, Tianjin, TJ 300052 (China)

2016-09-02

In this study, the performances of different preparation methods of the scaffolds were analyzed for chondrocyte tissue engineering. Silk fibroin/collagen (SF/C) was fabricated using a vacuum freeze-dried technique and by 3D printing. The porosity, water absorption expansion rates, mechanical properties, and pore sizes of the resulting materials were evaluated. The proliferation and metabolism of the cells was detected at different time points using an MTT assay. Cell morphologies and distributions were observed by histological analysis and scanning electron microscopy (SEM). The porosity, water absorption expansion rate, and Young’s modulus of the material obtained via 3D printing were significantly higher than those obtained by the freeze-dried method, while the pore size did not differ significantly between the two methods. MTT assay results showed that the metabolism of cells seeded on the 3D printed scaffolds was more viable than the metabolism on the freeze-dried material. H&E staining of the scaffolds revealed that the number of cells in the 3D printed scaffold was higher in comparison to a similar measurement on the freeze-dried material. Consequently, stem cells grew well inside the 3D printed scaffolds, as measured by SEM, while the internal structure of the freeze-dried scaffold was disordered. Compared with the freeze-dried technique, the 3D printed scaffold exhibited better overall performance and was more suitable for cartilage tissue engineering. - Highlights: • Silk fibroin/collagen was fabricated using 3D printing. • Physical characterization and Cell compatibility were compared. • 3D printed scaffold exhibited better overall performance.

Comparison of three-dimensional printing and vacuum freeze-dried techniques for fabricating composite scaffolds

International Nuclear Information System (INIS)

Sun, Kai; Li, Ruixin; Jiang, Wenxue; Sun, Yufu; Li, Hui

2016-01-01

In this study, the performances of different preparation methods of the scaffolds were analyzed for chondrocyte tissue engineering. Silk fibroin/collagen (SF/C) was fabricated using a vacuum freeze-dried technique and by 3D printing. The porosity, water absorption expansion rates, mechanical properties, and pore sizes of the resulting materials were evaluated. The proliferation and metabolism of the cells was detected at different time points using an MTT assay. Cell morphologies and distributions were observed by histological analysis and scanning electron microscopy (SEM). The porosity, water absorption expansion rate, and Young’s modulus of the material obtained via 3D printing were significantly higher than those obtained by the freeze-dried method, while the pore size did not differ significantly between the two methods. MTT assay results showed that the metabolism of cells seeded on the 3D printed scaffolds was more viable than the metabolism on the freeze-dried material. H&E staining of the scaffolds revealed that the number of cells in the 3D printed scaffold was higher in comparison to a similar measurement on the freeze-dried material. Consequently, stem cells grew well inside the 3D printed scaffolds, as measured by SEM, while the internal structure of the freeze-dried scaffold was disordered. Compared with the freeze-dried technique, the 3D printed scaffold exhibited better overall performance and was more suitable for cartilage tissue engineering. - Highlights: • Silk fibroin/collagen was fabricated using 3D printing. • Physical characterization and Cell compatibility were compared. • 3D printed scaffold exhibited better overall performance.

Dispositional mindfulness co-varies with smaller amygdala and caudate volumes in community adults.

Directory of Open Access Journals (Sweden)

Adrienne A Taren

Full Text Available Mindfulness, a psychological process reflecting attention and awareness to what is happening in the present moment, has been associated with increased well-being and decreased depression and anxiety in both healthy and patient populations. However, little research has explored underlying neural pathways. Recent work suggests that mindfulness (and mindfulness training interventions may foster neuroplastic changes in cortico-limbic circuits responsible for stress and emotion regulation. Building on this work, we hypothesized that higher levels of dispositional mindfulness would be associated with decreased grey matter volume in the amgydala. In the present study, a self-report measure of dispositional mindfulness and structural MRI images were obtained from 155 healthy community adults. Volumetric analyses showed that higher dispositional mindfulness is associated with decreased grey matter volume in the right amygdala, and exploratory analyses revealed that higher dispositional mindfulness is also associated with decreased grey matter volume in the left caudate. Moreover, secondary analyses indicate that these amygdala and caudate volume associations persist after controlling for relevant demographic and individual difference factors (i.e., age, total grey matter volume, neuroticism, depression. Such volumetric differences may help explain why mindful individuals have reduced stress reactivity, and suggest new candidate structural neurobiological pathways linking mindfulness with mental and physical health outcomes.

Dispositional Mindfulness Co-Varies with Smaller Amygdala and Caudate Volumes in Community Adults

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Taren, Adrienne A.; Creswell, J. David; Gianaros, Peter J.

2013-01-01

Mindfulness, a psychological process reflecting attention and awareness to what is happening in the present moment, has been associated with increased well-being and decreased depression and anxiety in both healthy and patient populations. However, little research has explored underlying neural pathways. Recent work suggests that mindfulness (and mindfulness training interventions) may foster neuroplastic changes in cortico-limbic circuits responsible for stress and emotion regulation. Building on this work, we hypothesized that higher levels of dispositional mindfulness would be associated with decreased grey matter volume in the amgydala. In the present study, a self-report measure of dispositional mindfulness and structural MRI images were obtained from 155 healthy community adults. Volumetric analyses showed that higher dispositional mindfulness is associated with decreased grey matter volume in the right amygdala, and exploratory analyses revealed that higher dispositional mindfulness is also associated with decreased grey matter volume in the left caudate. Moreover, secondary analyses indicate that these amygdala and caudate volume associations persist after controlling for relevant demographic and individual difference factors (i.e., age, total grey matter volume, neuroticism, depression). Such volumetric differences may help explain why mindful individuals have reduced stress reactivity, and suggest new candidate structural neurobiological pathways linking mindfulness with mental and physical health outcomes. PMID:23717632

[Experimental study of tissue engineered cartilage construction using oriented scaffold combined with bone marrow mesenchymal stem cells in vivo].

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Duan, Wei; Da, Hu; Wang, Wentao; Lü, Shangjun; Xiong, Zhuo; Liu, Jian

2013-05-01

To investigate the feasibility of fabricating an oriented scaffold combined with chondrogenic-induced bone marrow mesenchymal stem cells (BMSCs) for enhancement of the biomechanical property of tissue engineered cartilage in vivo. Temperature gradient-guided thermal-induced phase separation was used to fabricate an oriented cartilage extracellular matrix-derived scaffold composed of microtubules arranged in parallel in vertical section. No-oriented scaffold was fabricated by simple freeze-drying. Mechanical property of oriented and non-oriented scaffold was determined by measurement of compressive modulus. Oriented and non-oriented scaffolds were seeded with chondrogenic-induced BMSCs, which were obtained from the New Zealand white rabbits. Proliferation, morphological characteristics, and the distribution of the cells on the scaffolds were analyzed by MTT assay and scanning electron microscope. Then cell-scaffold composites were implanted subcutaneously in the dorsa of nude mice. At 2 and 4 weeks after implantation, the samples were harvested for evaluating biochemical, histological, and biomechanical properties. The compressive modulus of oriented scaffold was significantly higher than that of non-oriented scaffold (t=201.099, P=0.000). The cell proliferation on the oriented scaffold was significantly higher than that on the non-oriented scaffold from 3 to 9 days (P fibers with chondrocyte-like cells on the oriented-structure constructs. Total DNA, glycosaminoglycan (GAG), and collagen contents increased with time, and no significant difference was found between 2 groups (P > 0.05). The compressive modulus of the oriented tissue engineered cartilage was significantly higher than that of the non-oriented tissue engineered cartilage at 2 and 4 weeks after implantation (P < 0.05). Total DNA, GAG, collagen contents, and compressive modulus in the 2 tissue engineered cartilages were significantly lower than those in normal cartilage (P < 0.05). Oriented extracellular

Mechanosensation across borders: fibroblasts inside a macroporous scaffold sense and respond to the mechanical environment beyond the scaffold walls.

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Könnig, D; Herrera, A; Duda, G N; Petersen, A

2018-01-01

In tissue defects, cells face distinct mechanical boundary conditions, but how this influences early stages of tissue regeneration remains largely unknown. Biomaterials are used to fill defects but also to provide specific mechanical or geometrical signals. However, they might at the same time shield mechanical information from surrounding tissues that is relevant for tissue functionalisation. This study investigated how fibroblasts in a soft macroporous biomaterial scaffold respond to distinct mechanical environments while they form microtissues. Different boundary stiffnesses counteracting scaffold contraction were provided via a newly developed in vitro setup. Online monitoring over 14 days revealed 3.0 times lower microtissue contraction but 1.6 times higher contraction force for high vs. low stiffness. This difference was significant already after 48 h, a very early stage of microtissue growth. The microtissue's mechanical and geometrical adaptation indicated a collective cellular behaviour and mechanical communication across scaffold pore walls. Surprisingly, the stiffness of the environment influenced cell behaviour even inside macroporous scaffolds where direct cell-cell contacts are hindered. Mechanical communication between cells via traction forces is essential for tissue adaptation to the environment and should not be blocked by rigid biomaterials. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Mindfulness Meditation-Based Pain Relief Employs Different Neural Mechanisms Than Placebo and Sham Mindfulness Meditation-Induced Analgesia

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Emerson, Nichole M.; Farris, Suzan R.; Ray, Jenna N.; Jung, Youngkyoo; McHaffie, John G.; Coghill, Robert C.

2015-01-01

modulation. SIGNIFICANCE STATEMENT Recent findings have demonstrated that mindfulness meditation significantly reduces pain. Given that the “gold standard” for evaluating the efficacy of behavioral interventions is based on appropriate placebo comparisons, it is imperative that we establish whether there is an effect supporting meditation-related pain relief above and beyond the effects of placebo. Here, we provide novel evidence demonstrating that mindfulness meditation produces greater pain relief and employs distinct neural mechanisms than placebo cream and sham mindfulness meditation. Specifically, mindfulness meditation-induced pain relief activated higher-order brain regions, including the orbitofrontal and cingulate cortices. In contrast, placebo analgesia was associated with decreased pain-related brain activation. These findings demonstrate that mindfulness meditation reduces pain through unique mechanisms and may foster greater acceptance of meditation as an adjunct pain therapy. PMID:26586819

Scaffolds for bone regeneration made of hydroxyapatite microspheres in a collagen matrix

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Cholas, Rahmatullah, E-mail: rahmat.cholas@gmail.com; Kunjalukkal Padmanabhan, Sanosh, E-mail: sanosh2001@gmail.com; Gervaso, Francesca; Udayan, Gayatri; Monaco, Graziana; Sannino, Alessandro; Licciulli, Antonio

2016-06-01

drying • Compressive modulus of composite scaffold was higher than of pure collagen scaffold. • Cell proliferation with MG63 cells shows good biocompatiblity of composite scaffold.

Mindfulness Dampens Cardiac Responses to Motion Scenes of Violence.

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Brzozowski, Artur; Gillespie, Steven M; Dixon, Louise; Mitchell, Ian J

2018-01-01

Mindfulness is linked with improved regulatory processes of attention and emotion. The potential benefits of mindfulness are vast, including more positive emotional states and diminished arousal in response to emotional stimuli. This study aims to expand of the current knowledge of the mechanisms of mindfulness by relating the latter to cardiovascular processes. The paper describes two studies which investigated the relationship of trait mindfulness to self-report measures of emotions elicited during a violent video clip and cardiovascular responses to the clip. Both studies recruited male and female participants, mainly university undergraduate students. The clip was 5-min-long and evoked mainly feelings of tension and disgust. In study 1, we found that higher scores for trait mindfulness were associated with increased scores for valence ( r  = .370, p  = .009), indicating a more positive interpretation of the clip. In study 2, the average heart rate during the clip was lower than during the preceding ( p  mindfulness was related to diminished heart rate reactivity ( r  = -.364, p  = .044) and recovery ( r  = -.415, p  = .020). This latter effect was obtained only when trait anxiety was used as a statistical covariate. Additionally, increased trait mindfulness was accompanied by higher resting heart rate ( r  = .390, p  = .027). These outcomes suggest that mindfulness is linked with reductions in negative feelings evoked by violent motion stimuli.

Microwell Scaffolds for the Extrahepatic Transplantation of Islets of Langerhans

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Buitinga, Mijke; Truckenmüller, Roman; Engelse, Marten A.; Moroni, Lorenzo; Ten Hoopen, Hetty W. M.; van Blitterswijk, Clemens A.; de Koning, Eelco JP.; van Apeldoorn, Aart A.; Karperien, Marcel

2013-01-01

Allogeneic islet transplantation into the liver has the potential to restore normoglycemia in patients with type 1 diabetes. However, the suboptimal microenvironment for islets in the liver is likely to be involved in the progressive islet dysfunction that is often observed post-transplantation. This study validates a novel microwell scaffold platform to be used for the extrahepatic transplantation of islet of Langerhans. Scaffolds were fabricated from either a thin polymer film or an electrospun mesh of poly(ethylene oxide terephthalate)-poly(butylene terephthalate) (PEOT/PBT) block copolymer (composition: 4000PEOT30PBT70) and were imprinted with microwells, ∼400 µm in diameter and ∼350 µm in depth. The water contact angle and water uptake were 39±2° and 52.1±4.0 wt%, respectively. The glucose flux through electrospun scaffolds was three times higher than for thin film scaffolds, indicating enhanced nutrient diffusion. Human islets cultured in microwell scaffolds for seven days showed insulin release and insulin content comparable to those of free-floating control islets. Islet morphology and insulin and glucagon expression were maintained during culture in the microwell scaffolds. Our results indicate that the microwell scaffold platform prevents islet aggregation by confinement of individual islets in separate microwells, preserves the islet’s native rounded morphology, and provides a protective environment without impairing islet functionality, making it a promising platform for use in extrahepatic islet transplantation. PMID:23737999

Electrospinning PCL Scaffolds Manufacture for Three-Dimensional Breast Cancer Cell Culture

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Marc Rabionet

2017-08-01

Full Text Available In vitro cell culture is traditionally performed within two-dimensional (2D environments, providing a quick and cheap way to study cell properties in a laboratory. However, 2D systems differ from the in vivo environment and may not mimic the physiological cell behavior realistically. For instance, 2D culture models are thought to induce cancer stem cells (CSCs differentiation, a rare cancer cell subpopulation responsible for tumor initiation and relapse. This fact hinders the development of therapeutic strategies for tumors with a high relapse percentage, such as triple negative breast cancer (TNBC. Thus, three-dimensional (3D scaffolds have emerged as an attractive alternative to monolayer culture, simulating the extracellular matrix structure and maintaining the differentiation state of cells. In this work, scaffolds were fabricated through electrospinning different poly(ε-caprolactone-acetone solutions. Poly(ε-caprolactone (PCL meshes were seeded with triple negative breast cancer (TNBC cells and 15% PCL scaffolds displayed significantly (p < 0.05 higher cell proliferation and elongation than the other culture systems. Moreover, cells cultured on PCL scaffolds exhibited higher mammosphere forming capacity and aldehyde dehydrogenase activity than 2D-cultured cells, indicating a breast CSCs enrichment. These results prove the powerful capability of electrospinning technology in terms of poly(ε-caprolactone nanofibers fabrication. In addition, this study has demonstrated that electrospun 15% PCL scaffolds are suitable tools to culture breast cancer cells in a more physiological way and to expand the niche of breast CSCs. In conclusion, three-dimensional cell culture using PCL scaffolds could be useful to study cancer stem cell behavior and may also trigger the development of new specific targets against such malignant subpopulation.

Hyaluronic acid doped-poly(3,4-ethylenedioxythiophene)/chitosan/gelatin (PEDOT-HA/Cs/Gel) porous conductive scaffold for nerve regeneration

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Wang, Shuping; Guan, Shui; Zhu, Zhibo; Li, Wenfang; Liu, Tianqing; Ma, Xuehu

2017-01-01

Conducting polymer, as a “smart” biomaterial, has been increasingly used to construct tissue engineered scaffold for nerve tissue regeneration. In this study, a novel porous conductive scaffold was prepared by incorporating conductive hyaluronic acid (HA) doped-poly(3,4-ethylenedioxythiophene) (PEDOT-HA) nanoparticles into a chitosan/gelatin (Cs/Gel) matrix. The physicochemical characteristics of Cs/Gel scaffold with 0–10 wt% PEDOT-HA were analyzed and the results indicated that the incorporation of PEDOT-HA into scaffold increased the electrical and mechanical properties while decreasing the porosity and water absorption. Moreover, in vitro biodegradation of scaffold displayed a declining trend with the PEDOT-HA content increased. About the biocompatibility of conductive scaffold, neuron-like rat phaeochromocytoma (PC12) cells were cultured in scaffold to evaluate cell adhesion and growth. 8% PEDOT-HA/Cs/Gel scaffold had a higher cell adhesive efficiency and cell viability than the other conductive scaffolds. Furthermore, cells in the scaffold with 8 wt% PEDOT-HA expressed higher synapse growth gene of GAP43 and SYP compared with Cs/Gel control group. These results suggest that 8%PEDOT-HA/Cs/Gel scaffold is an attractive cell culture conductive substrate which could support cell adhesion, survival, proliferation, and synapse growth for the application in nerve tissue regeneration. - Highlights: • A porous conductive scaffold was prepared by freeze-drying method. • Conductive scaffold could support PC12 cells adhesion, survival, and proliferation. • Cells in conductive scaffold expressed high synapse growth gene of GAP43 and SYP.

Hyaluronic acid doped-poly(3,4-ethylenedioxythiophene)/chitosan/gelatin (PEDOT-HA/Cs/Gel) porous conductive scaffold for nerve regeneration

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Wang, Shuping; Guan, Shui, E-mail: guanshui@dlut.edu.cn; Zhu, Zhibo; Li, Wenfang; Liu, Tianqing; Ma, Xuehu

2017-02-01

Conducting polymer, as a “smart” biomaterial, has been increasingly used to construct tissue engineered scaffold for nerve tissue regeneration. In this study, a novel porous conductive scaffold was prepared by incorporating conductive hyaluronic acid (HA) doped-poly(3,4-ethylenedioxythiophene) (PEDOT-HA) nanoparticles into a chitosan/gelatin (Cs/Gel) matrix. The physicochemical characteristics of Cs/Gel scaffold with 0–10 wt% PEDOT-HA were analyzed and the results indicated that the incorporation of PEDOT-HA into scaffold increased the electrical and mechanical properties while decreasing the porosity and water absorption. Moreover, in vitro biodegradation of scaffold displayed a declining trend with the PEDOT-HA content increased. About the biocompatibility of conductive scaffold, neuron-like rat phaeochromocytoma (PC12) cells were cultured in scaffold to evaluate cell adhesion and growth. 8% PEDOT-HA/Cs/Gel scaffold had a higher cell adhesive efficiency and cell viability than the other conductive scaffolds. Furthermore, cells in the scaffold with 8 wt% PEDOT-HA expressed higher synapse growth gene of GAP43 and SYP compared with Cs/Gel control group. These results suggest that 8%PEDOT-HA/Cs/Gel scaffold is an attractive cell culture conductive substrate which could support cell adhesion, survival, proliferation, and synapse growth for the application in nerve tissue regeneration. - Highlights: • A porous conductive scaffold was prepared by freeze-drying method. • Conductive scaffold could support PC12 cells adhesion, survival, and proliferation. • Cells in conductive scaffold expressed high synapse growth gene of GAP43 and SYP.

Crosslinked pullulan/cellulose acetate fibrous scaffolds for bone tissue engineering

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Atila, Deniz [Department of Engineering Sciences, Middle East Technical University (Turkey); Keskin, Dilek [Department of Engineering Sciences, Middle East Technical University (Turkey); Biomaterials and Tissue Engineering Center of Excellence, Middle East Technical University (Turkey); Tezcaner, Ayşen, E-mail: tezcaner@metu.edu.tr [Department of Engineering Sciences, Middle East Technical University (Turkey); Biomaterials and Tissue Engineering Center of Excellence, Middle East Technical University (Turkey)

2016-12-01

Natural polymer based fibrous scaffolds have been explored for bone tissue engineering applications; however, their inadequate 3-dimensionality and poor mechanical properties are among the concerns for their use as bone substitutes. In this study, pullulan (P) and cellulose acetate (CA), two polysaccharides, were electrospun at various P/CA ratios (P{sub 80}/CA{sub 20}, P{sub 50}/CA{sub 50}, and P{sub 20}/CA{sub 80}%) to develop 3D fibrous network. The scaffolds were then crosslinked with trisodium trimetaphosphate (STMP) to improve the mechanical properties and to delay fast weight loss. The lowest weight loss was observed for the groups that were crosslinked with P/STMP 2/1 for 10 min. Fiber morphologies of P{sub 50}/CA{sub 50} were more uniform without phase separation and this group was crosslinked most efficiently among groups. It was found that mechanical properties of P{sub 20}/CA{sub 80} and P{sub 50}/CA{sub 50} were higher than that of P{sub 80}/CA{sub 20.} After crosslinking strain values of P{sub 50}/CA{sub 50} scaffolds were improved and these scaffolds became more stable. Unlike P{sub 80}/CA{sub 20,} uncrosslinked P{sub 50}/CA{sub 50} and P{sub 20}/CA{sub 80} were not lost in PBS. Among all groups, crosslinked P{sub 50}/CA{sub 50} scaffolds had more uniform pores; therefore this group was used for bioactivity and cell culture studies. Apatite-like structures were observed on fibers after SBF incubation. Human Osteogenic Sarcoma Cell Line (Saos-2) seeded onto crosslinked P{sub 50}/CA{sub 50} scaffolds adhered and proliferated. The functionality of cells was tested by measuring ALP activity of the cells and the results indicated their osteoblastic differentiation. In vitro tests showed that scaffolds were cytocompatible. To sum up, crosslinked P{sub 50}/CA{sub 50} scaffolds were proposed as candidate cell carriers for bone tissue engineering applications. - Highlights: • Crosslinked 3D electrospun P/CA scaffolds were prepared for the first time. • CA

Indirect three-dimensional printing of synthetic polymer scaffold based on thermal molding process

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Park, Jeong Hun; Jung, Jin Woo; Cho, Dong-Woo; Kang, Hyun-Wook

2014-01-01

One of the major issues in tissue engineering has been the development of three-dimensional (3D) scaffolds, which serve as a structural template for cell growth and extracellular matrix formation. In scaffold-based tissue engineering, 3D printing (3DP) technology has been successfully applied for the fabrication of complex 3D scaffolds by using both direct and indirect techniques. In principle, direct 3DP techniques rely on the straightforward utilization of the final scaffold materials during the actual scaffold fabrication process. In contrast, indirect 3DP techniques use a negative mold based on a scaffold design, to which the desired biomaterial is cast and then sacrificed to obtain the final scaffold. Such indirect 3DP techniques generally impose a solvent-based process for scaffold fabrication, resulting in a considerable increase in the fabrication time and poor mechanical properties. In addition, the internal architecture of the resulting scaffold is affected by the properties of the biomaterial solution. In this study, we propose an advanced indirect 3DP technique using projection-based micro-stereolithography and an injection molding system (IMS) in order to address these challenges. The scaffold was fabricated by a thermal molding process using IMS to overcome the limitation of the solvent-based molding process in indirect 3DP techniques. The results indicate that the thermal molding process using an IMS has achieved a substantial reduction in scaffold fabrication time and has also provided the scaffold with higher mechanical modulus and strength. In addition, cell adhesion and proliferation studies have indicated no significant difference in cell activity between the scaffolds prepared by solvent-based and thermal molding processes. (paper)

Mindful Emotion Regulation: Exploring the Neurocognitive Mechanisms behind Mindfulness

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Alessandro Grecucci

2015-01-01

Full Text Available The purpose of this paper is to review some of the psychological and neural mechanisms behind mindfulness practice in order to explore the unique factors that account for its positive impact on emotional regulation and health. After reviewing the mechanisms of mindfulness and its effects on clinical populations we will consider how the practice of mindfulness contributes to the regulation of emotions. We argue that mindfulness has achieved effective outcomes in the treatment of anxiety, depression, and other psychopathologies through the contribution of mindfulness to emotional regulation. We consider the unique factors that mindfulness meditation brings to the process of emotion regulation that may account for its effectiveness. We review experimental evidence that points towards the unique effects of mindfulness specifically operating over and above the regulatory effects of cognitive reappraisal mechanisms. A neuroanatomical circuit that leads to mindful emotion regulation is also suggested. This paper thereby aims to contribute to proposed models of mindfulness for research and theory building by proposing a specific model for the unique psychological and neural processes involved in mindful detachment that account for the effects of mindfulness over and above the effects accounted for by other well-established emotional regulation processes such as cognitive reappraisal.

Analog series-based scaffolds: computational design and exploration of a new type of molecular scaffolds for medicinal chemistry

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Dimova, Dilyana; Stumpfe, Dagmar; Hu, Ye; Bajorath, Jürgen

2016-01-01

Aim: Computational design of and systematic search for a new type of molecular scaffolds termed analog series-based scaffolds. Materials & methods: From currently available bioactive compounds, analog series were systematically extracted, key compounds identified and new scaffolds isolated from them. Results: Using our computational approach, more than 12,000 scaffolds were extracted from bioactive compounds. Conclusion: A new scaffold definition is introduced and a computational methodology developed to systematically identify such scaffolds, yielding a large freely available scaffold knowledge base. PMID:28116132

Use of Interim Scaffolding and Neotissue Development to Produce a Scaffold-Free Living Hyaline Cartilage Graft.

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Lau, Ting Ting; Leong, Wenyan; Peck, Yvonne; Su, Kai; Wang, Dong-An

2015-01-01

The fabrication of three-dimensional (3D) constructs relies heavily on the use of biomaterial-based scaffolds. These are required as mechanical supports as well as to translate two-dimensional cultures to 3D cultures for clinical applications. Regardless of the choice of scaffold, timely degradation of scaffolds is difficult to achieve and undegraded scaffold material can lead to interference in further tissue development or morphogenesis. In cartilage tissue engineering, hydrogel is the highly preferred scaffold material as it shares many similar characteristics with native cartilaginous matrix. Hence, we employed gelatin microspheres as porogens to create a microcavitary alginate hydrogel as an interim scaffold to facilitate initial chondrocyte 3D culture and to establish a final scaffold-free living hyaline cartilaginous graft (LhCG) for cartilage tissue engineering.

Combining technologies to create bioactive hybrid scaffolds for bone tissue engineering.

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Nandakumar, Anandkumar; Barradas, Ana; de Boer, Jan; Moroni, Lorenzo; van Blitterswijk, Clemens; Habibovic, Pamela

2013-01-01

Combining technologies to engineer scaffolds that can offer physical and chemical cues to cells is an attractive approach in tissue engineering and regenerative medicine. In this study, we have fabricated polymer-ceramic hybrid scaffolds for bone regeneration by combining rapid prototyping (RP), electrospinning (ESP) and a biomimetic coating method in order to provide mechanical support and a physico-chemical environment mimicking both the organic and inorganic phases of bone extracellular matrix (ECM). Poly(ethylene oxide terephthalate)-poly(buthylene terephthalate) (PEOT/PBT) block copolymer was used to produce three dimensional scaffolds by combining 3D fiber (3DF) deposition, and ESP, and these constructs were then coated with a Ca-P layer in a simulated physiological solution. Scaffold morphology and composition were studied using scanning electron microscopy (SEM) coupled to energy dispersive X-ray analyzer (EDX) and Fourier Tranform Infrared Spectroscopy (FTIR). Bone marrow derived human mesenchymal stromal cells (hMSCs) were cultured on coated and uncoated 3DF and 3DF + ESP scaffolds for up to 21 d in basic and mineralization medium and cell attachment, proliferation, and expression of genes related to osteogenesis were assessed. Cells attached, proliferated and secreted ECM on all the scaffolds. There were no significant differences in metabolic activity among the different groups on days 7 and 21. Coated 3DF scaffolds showed a significantly higher DNA amount in basic medium at 21 d compared with the coated 3DF + ESP scaffolds, whereas in mineralization medium, the presence of coating in 3DF+ESP scaffolds led to a significant decrease in the amount of DNA. An effect of combining different scaffolding technologies and material types on expression of a number of osteogenic markers (cbfa1, BMP-2, OP, OC and ON) was observed, suggesting the potential use of this approach in bone tissue engineering.

Mindfulness Meditation-Based Pain Relief Employs Different Neural Mechanisms Than Placebo and Sham Mindfulness Meditation-Induced Analgesia.

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Zeidan, Fadel; Emerson, Nichole M; Farris, Suzan R; Ray, Jenna N; Jung, Youngkyoo; McHaffie, John G; Coghill, Robert C

2015-11-18

significantly reduces pain. Given that the "gold standard" for evaluating the efficacy of behavioral interventions is based on appropriate placebo comparisons, it is imperative that we establish whether there is an effect supporting meditation-related pain relief above and beyond the effects of placebo. Here, we provide novel evidence demonstrating that mindfulness meditation produces greater pain relief and employs distinct neural mechanisms than placebo cream and sham mindfulness meditation. Specifically, mindfulness meditation-induced pain relief activated higher-order brain regions, including the orbitofrontal and cingulate cortices. In contrast, placebo analgesia was associated with decreased pain-related brain activation. These findings demonstrate that mindfulness meditation reduces pain through unique mechanisms and may foster greater acceptance of meditation as an adjunct pain therapy. Copyright © 2015 the authors 0270-6474/15/3515308-19$15.00/0.

Understanding Resident Performance, Mindfulness, and Communication in Critical Care Rotations.

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Real, Kevin; Fields-Elswick, Katelyn; Bernard, Andrew C

Evidence from the medical literature suggests that surgical trainees can benefit from mindful practices. Surgical educators are challenged with the need to address resident core competencies, some of which may be facilitated by higher levels of mindfulness. This study explores whether mindful residents perform better than their peers as members of the health care team. This study employed a multiphase, multimethod design to assess resident mindfulness, communication, and clinical performance. Academic, tertiary medical center. Residents (N = 51) working in an intensive care unit. In phase I, medical residents completed a self-report survey of mindfulness, communication, emotional affect, and clinical decision-making. In phase II, resident performance was assessed using independent ratings of mindfulness and clinical decision-making by attending physicians and registered nurses. In phase 1, a significant positive relationship was found between resident performance and mindfulness, positive affect (PA), and communication. In phase 2, attending physicians/registered nurses' perceptions of residents' mindfulness were positively correlated with communication and inversely related to negative affect (NA). The top quartile of residents for performance and mindfulness had the lowest NA. Higher-rated residents underestimated their performance/mindfulness, whereas those in the lowest quartile overestimated these factors. This study offers a number of implications for medical resident education. First, mindfulness was perceived to be a significant contributor to self-assessments of competency and performance. Second, both PA and NA were important to mindfulness and performance. Third, communication was associated with resident performance, mindfulness, and PA. These implications suggest that individual characteristics of mindfulness, communication, and affect, all potentially modifiable, influence care quality and safety. To improve low performers, surgical educators could

Hybrid chitosan-ß-glycerol phosphate-gelatin nano-/micro fibrous scaffolds with suitable mechanical and biological properties for tissue engineering.

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Lotfi, Marzieh; Bagherzadeh, Roohollah; Naderi-Meshkin, Hojjat; Mahdipour, Elahe; Mafinezhad, Asghar; Sadeghnia, Hamid Reza; Esmaily, Habibollah; Maleki, Masoud; Hasssanzadeh, Halimeh; Ghayaour-Mobarhan, Majid; Bidkhori, Hamid Reza; Bahrami, Ahmad Reza

2016-03-01

Scaffold-based tissue engineering is considered as a promising approach in the regenerative medicine. Graft instability of collagen, by causing poor mechanical properties and rapid degradation, and their hard handling remains major challenges to be addressed. In this research, a composite structured nano-/microfibrous scaffold, made from a mixture of chitosan-ß-glycerol phosphate-gelatin (chitosan-GP-gelatin) using a standard electrospinning set-up was developed. Gelatin-acid acetic and chitosan ß-glycerol phosphate-HCL solutions were prepared at ratios of 30/70, 50/50, 70/30 (w/w) and their mechanical and biological properties were engineered. Furthermore, the pore structure of the fabricated nanofibrous scaffolds was investigated and predicted using a theoretical model. Higher gelatin concentrations in the polymer blend resulted in significant increase in mean pore size and its distribution. Interaction between the scaffold and the contained cells was also monitored and compared in the test and control groups. Scaffolds with higher chitosan concentrations showed higher rate of cell attachment with better proliferation property, compared with gelatin-only scaffolds. The fabricated scaffolds, unlike many other natural polymers, also exhibit non-toxic and biodegradable properties in the grafted tissues. In conclusion, the data clearly showed that the fabricated biomaterial is a biologically compatible scaffold with potential to serve as a proper platform for retaining the cultured cells for further application in cell-based tissue engineering, especially in wound healing practices. These results suggested the potential of using mesoporous composite chitosan-GP-gelatin fibrous scaffolds for engineering three-dimensional tissues with different inherent cell characteristics. © 2015 Wiley Periodicals, Inc.

Graphene-containing PCL- coated Porous 13-93B3 Bioactive Glass Scaffolds for Bone Regeneration

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Türk, Mert; Deliormanlı, Aylin M.

2018-04-01

Borate-based 13-93B3 bioactive glass scaffolds were coated with the graphene-containing poly-caprolactone (PCL) solution to prepare electrically conductive composites for biomedical applications. Results revealed that electrical conductivity of the scaffolds increased with increasing concentration of graphene nanoparticles. Significant difference was not observed in hydroxyapatite forming ability of the bare and the graphene-containing scaffolds immersed in simulated body fluid. In vitro cytotoxicity experiments (XTT tests) showed that pre-osteoblastic MC3T3-E1 cell viability percentages of the graphene- containing samples was higher than control group samples after 7 days of incubation. However, a decrease in cell viability rates was obtained after 14 days of incubation for samples coated with PCL containing graphene starting from 3 wt%. Additionally, results obtained in the live-dead assay were consistent with the results of XTT tests. A higher ALP activity was detected in cells cultured on the graphene-containing borate glass scaffolds than those on the bare PCL coated 13-93B3 scaffolds suggesting the presence of graphene nanopowders stimulated an early stage of osteoblastic differentiation. SEM analysis showed that MC3T3-E1 cells exhibited a flat appearance and spread out through the surface in all groups of scaffolds starting from 3 days of incubation.

Fabrication and Characteristics of Chitosan Sponge as a Tissue Engineering Scaffold

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Takeshi Ikeda

2014-01-01

Full Text Available Cells, growth factors, and scaffolds are the three main factors required to create a tissue-engineered construct. After the appearance of bovine spongiform encephalopathy (BSE, considerable attention has therefore been focused on nonbovine materials. In this study, we examined the properties of a chitosan porous scaffold. A porous chitosan sponge was prepared by the controlled freezing and lyophilization of different concentrations of chitosan solutions. The materials were examined by scanning electron microscopy, and the porosity, tensile strength, and basic fibroblast growth factor (bFGF release profiles from chitosan sponge were examined in vitro. The morphology of the chitosan scaffolds presented a typical microporous structure, with the pore size ranging from 50 to 200 μm. The porosity of chitosan scaffolds with different concentrations was approximately 75–85%. A decreasing tendency for porosity was observed as the concentration of the chitosan increased. The relationship between the tensile properties and chitosan concentration indicated that the ultimate tensile strength for the sponge increased with a higher concentration. The in vitro bFGF release study showed that the higher the concentration of chitosan solution became, the longer the releasing time of the bFGF from the chitosan sponge was.

Oculometric variations during mind wandering

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Romain eGrandchamp

2014-02-01

Full Text Available A significant body of literature supports the contention that pupil size varies depending on cognitive load, affective state, and level of drowsiness. Here we assessed whether oculometric measures such as gaze position, blink frequency and pupil size were correlated with the occurrence and time course of self-reported mind-wandering episodes. We recorded the pupil size of two subjects engaged in a monotonous breath counting task while keeping their eyes on a fixation cross. Each subject performed ten 20-minute sessions, for total duration of about 4 hours. This task is conducive to producing mind-wandering episodes. Subjects were instructed to report spontaneous mind-wandering episodes by pressing a button when they lost count of their breath. After each button press, subjects filled in a short questionnaire describing the characteristics of their mind-wandering episode. We observed larger pupil size during the breath-focusing period compared to the mind-wandering period (p< 0.01 for both subjects. Our findings contradict previous research showing a higher baseline pupil size during mind wandering episodes in visual tasks. We discuss possible explanations for this discrepancy. We also analyzed nine other oculometric measures including blink rate, blink duration and gaze position. We built a support vector machine classifier and showed that mean pupil size was the most reliable predictors of mind wandering in both subjects. The classification accuracy of mind wandering data segments versus breath-focusing data segments was 81% for the first subject and 77% for the second subject. Additionally, we analyzed oculometric measures in light of the phenomenological data collected in the questionnaires. We showed that how well subjects remembered their thoughts while mind wandering was positively correlated with pupil size (subject 1, p< 0.001; subject 2, p< 0.05. Feelings of well being were also positively correlated with pupil size (subject 1, p< 0

Antimicrobial Cu-bearing stainless steel scaffolds

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Wang, Qiang, E-mail: mfqwang@163.com [School of Stomatology, China Medical University, Shenyang 110002 (China); Ren, Ling [Institute of Metal Research, Chinese Academy of Sciences (China); Li, Xiaopeng [School of Mechanical and Chemical Engineering, The University of Western Australia (Australia); Zhang, Shuyuan [Institute of Metal Research, Chinese Academy of Sciences (China); Sercombe, Timothy B., E-mail: tim.sercombe@uwa.edu.au [School of Mechanical and Chemical Engineering, The University of Western Australia (Australia); Yang, Ke, E-mail: kyang@imr.ac.cn [Institute of Metal Research, Chinese Academy of Sciences (China)

2016-11-01

Copper-bearing stainless steel scaffolds with two different structures (Body Centered Cubic and Gyroid labyrinth) at two solid fractions (25% and 40%) were fabricated from both 316L powder and a mixture of 316L and elemental Cu powder using selective laser melting, and relative 316L scaffolds were served as control group. After processing, the antimicrobial testing demonstrated that the 316L-Cu scaffolds presented excellent antimicrobial activity against Escherichia coli and Staphylococcus aureus, and the cell viability assay indicated that there was no cytotoxic effect of 316L-Cu scaffolds on rat marrow mesenchymal stem cells. As such, these have the potential to reduce implant-associated infections. The Cu was also found to homogeneously distribute within the microstructure by scanning electronic microcopy. The addition of Cu would not significantly affect its strength and stiffness compared to 316L scaffold, and the stiffness of all the scaffolds (3-20GPa) is similar to that of bone and much less than that of bulk stainless steel. Consequently, fabrication of such low stiffness porous structures, especially coupled with the addition of antimicrobial Cu, may provide a new direction for medical stainless steels. - Highlights: • 316L-Cu scaffolds were fabricated by using selective laser melting (SLM). • 316L-Cu scaffolds showed satisfied antimicrobial activities. • 316L-Cu scaffolds have no cytotoxic effect on normal cells. • Other properties of 316L-Cu scaffolds were similar to 316L scaffolds. • 316L-Cu scaffolds have the potential to be used in orthopedic applications.

Antimicrobial Cu-bearing stainless steel scaffolds

International Nuclear Information System (INIS)

Wang, Qiang; Ren, Ling; Li, Xiaopeng; Zhang, Shuyuan; Sercombe, Timothy B.; Yang, Ke

2016-01-01

Copper-bearing stainless steel scaffolds with two different structures (Body Centered Cubic and Gyroid labyrinth) at two solid fractions (25% and 40%) were fabricated from both 316L powder and a mixture of 316L and elemental Cu powder using selective laser melting, and relative 316L scaffolds were served as control group. After processing, the antimicrobial testing demonstrated that the 316L-Cu scaffolds presented excellent antimicrobial activity against Escherichia coli and Staphylococcus aureus, and the cell viability assay indicated that there was no cytotoxic effect of 316L-Cu scaffolds on rat marrow mesenchymal stem cells. As such, these have the potential to reduce implant-associated infections. The Cu was also found to homogeneously distribute within the microstructure by scanning electronic microcopy. The addition of Cu would not significantly affect its strength and stiffness compared to 316L scaffold, and the stiffness of all the scaffolds (3-20GPa) is similar to that of bone and much less than that of bulk stainless steel. Consequently, fabrication of such low stiffness porous structures, especially coupled with the addition of antimicrobial Cu, may provide a new direction for medical stainless steels. - Highlights: • 316L-Cu scaffolds were fabricated by using selective laser melting (SLM). • 316L-Cu scaffolds showed satisfied antimicrobial activities. • 316L-Cu scaffolds have no cytotoxic effect on normal cells. • Other properties of 316L-Cu scaffolds were similar to 316L scaffolds. • 316L-Cu scaffolds have the potential to be used in orthopedic applications.

Electrophysiological Correlates of Reading the Single- and Interactive-Mind

Science.gov (United States)

Wang, Yi-Wen; Zheng, Yu-Wei; Lin, Chong-De; Wu, Jie; Shen, De-Li

2011-01-01

Understanding minds is the cognitive basis of successful social interaction. In everyday life, human mental activity often happens at the moment of social interaction among two or multiple persons instead of only one-person. Understanding the interactive mind of two- or multi-person is more complex and higher than understanding the single-person mind in the hierarchical structure of theory of mind. Understanding the interactive mind maybe differentiate from understanding the single mind. In order to examine the dissociative electrophysiological correlates of reading the single mind and reading the interactive mind, the 64 channels event-related potentials were recorded while 16 normal adults were observing three kinds of Chinese idioms depicted physical scenes, one-person with mental activity, and two- or multi-person with mental interaction. After the equivalent N400, in the 500- to 700-ms epoch, the mean amplitudes of late positive component (LPC) over frontal for reading the single mind and reading the interactive mind were significantly more positive than for physical representation, while there was no difference between the former two. In the 700- to 800-ms epoch, the mean amplitudes of LPC over frontal–central for reading the interactive mind were more positive than for reading the single mind and physical representation, while there was no difference between the latter two. The present study provides electrophysiological signature of the dissociations between reading the single mind and reading the interactive mind. PMID:21845178

Electrophysiological correlates of reading the single- and interactive-mind

Directory of Open Access Journals (Sweden)

Yi-Wen eWang

2011-07-01

Full Text Available Understanding minds is the cognitive basis of successful social interaction. In everyday life, human mental activity often happens at the moment of social interaction among two or multiple persons instead of only one person. Understanding the interactive mind of two- or multi-person is more complex and higher than understanding the single-person mind in the hierarchical structure of theory-of-mind. Understanding the interactive mind maybe differentiate from understanding the single mind. In order to examine the dissociative electrophysiological correlates of reading the single mind and reading the interactive mind, the 64 channels event-related potentials (ERP were recorded while 16 normal adults were observing three kinds of Chinese idioms depicted physical scenes, one-person with mental activity and two- or multi-person with mental interaction. After the equivalent N400, in the 500- to 700-ms epoch, the mean amplitudes of late positive component (LPC over frontal for reading the single mind and reading the interactive mind were significantly more positive than for physical representation, while there was no difference between the former two. In the 700-to 800-ms epoch, the mean amplitudes of LPC over frontal-central for reading the interactive mind were more positive than for reading the single mind and physical representation, while there was no difference between the latter two. The present study provides electrophysiological signature of the dissociations between reading the single mind and reading the interactive mind.

In vitro biocompatibility of 45S5 Bioglass-derived glass-ceramic scaffolds coated with poly(3-hydroxybutyrate).

Science.gov (United States)

Bretcanu, Oana; Misra, Superb; Roy, Ipsita; Renghini, Chiara; Fiori, Fabrizio; Boccaccini, Aldo R; Salih, Vehid

2009-02-01

The aim of this work was to study the in vitro biocompatibility of glass-ceramic scaffolds based on 45S5 Bioglass, using a human osteosarcoma cell line (HOS-TE85). The highly porous scaffolds were produced by the foam replication technique. Two different types of scaffolds with different porosities were analysed. They were coated with a biodegradable polymer, poly(3-hydroxybutyrate) (P(3HB)). The scaffold bioactivity was evaluated by soaking in a simulated body fluid (SBF) for different durations. Compression strength tests were performed before and after immersion in SBF. These experiments showed that the scaffolds are highly bioactive, as after a few days of immersion in SBF a hydroxyapatite-like layer was formed on the scaffold's surface. It was also observed that P(3HB)-coated samples exhibited higher values of compression strength than uncoated samples. Biocompatibility assessment was carried out by qualitative evaluation of cell morphology after different culture periods, using scanning electron microscopy, while cell proliferation was determined by using the AlamarBlue assay. Alkaline phosphatase (ALP) and osteocalcin (OC) assays were used as quantitative in vitro indicators of osteoblast function. Two different types of medium were used for ALP and OC tests: normal supplemented medium and osteogenic medium. HOS cells were seeded and cultured onto the scaffolds for up to 2 weeks. The AlamarBlue assay showed that cells were able to proliferate and grow on the scaffold surface. After 7 days in culture, the P(3HB)-coated samples had a higher number of cells on their surfaces than the uncoated samples. Regarding ALP- and OC-specific activity, no significant differences were found between samples with different pore sizes. All scaffolds containing osteogenic medium seemed to have a slightly higher level of ALP and OC concentration. These experiments confirmed that Bioglass/P(3HB) scaffolds have potential as osteoconductive tissue engineering substrates for

Fabrication and Characterization of Collagen-Immobilized Porous PHBV/HA Nano composite Scaffolds for Bone Tissue Engineering

International Nuclear Information System (INIS)

Jin-Young, B.; Zhi-Cai, X.; Giseop, K.; Keun-Byoung, Y.; Soo-Young, P.; Lee, S.P.; Inn-Kyu, K.

2012-01-01

The porous composite scaffolds (PHBV/HA) consisting of poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and hydroxyapatite (HA) were fabricated using a hot-press machine and salt-leaching. Collagen (type I) was then immobilized on the surface of the porous PHBV/HA composite scaffolds to improve tissue compatibility. The structure and morphology of the collagen-immobilized composite scaffolds (PHBV/HA/Col) were investigated using a scanning electron microscope (SEM), Fourier transform infrared (FTIR), and electron spectroscopy for chemical analysis (ESCA). The potential of the porous PHBV/HA/Col composite scaffolds for use as a bone scaffold was assessed by an experiment with osteoblast cells (MC3T3-E1) in terms of cell adhesion, proliferation, and differentiation. The results showed that the PHBV/HA/Col composite scaffolds possess better cell adhesion and significantly higher proliferation and differentiation than the PHBV/HA composite scaffolds and the PHBV scaffolds. These results suggest that the PHBV/HA/Col composite scaffolds have a high potential for use in the field of bone regeneration and tissue engineering.

Computational design of new molecular scaffolds for medicinal chemistry, part II: generalization of analog series-based scaffolds

Science.gov (United States)

Dimova, Dilyana; Stumpfe, Dagmar; Bajorath, Jürgen

2018-01-01

Aim: Extending and generalizing the computational concept of analog series-based (ASB) scaffolds. Materials & methods: Methodological modifications were introduced to further increase the coverage of analog series (ASs) and compounds by ASB scaffolds. From bioactive compounds, ASs were systematically extracted and second-generation ASB scaffolds isolated. Results: More than 20,000 second-generation ASB scaffolds with single or multiple substitution sites were extracted from active compounds, achieving more than 90% coverage of ASs. Conclusion: Generalization of the ASB scaffold approach has yielded a large knowledge base of scaffold-capturing compound series and target information. PMID:29379641

Trait mindfulness helps shield decision-making from translating into health-risk behavior.

Science.gov (United States)

Black, David S; Sussman, Steve; Johnson, C Anderson; Milam, Joel

2012-12-01

The cognitive tendency toward mindfulness may influence the enactment of health and risk behaviors by its bringing increased attention to and awareness of decision-making processes underlying behavior. The present study examined the moderating effect of trait mindfulness on associations between intentions to smoke (ITS)/smoking refusal self-efficacy (SRSE) and smoking frequency. Self-reports from Chinese adolescents (N = 5,287; mean age = 16.2 years, standard deviation = .7; 48.8% female) were collected in 24 schools. Smoking frequency was regressed on latent factor interactions Mindful Attention Awareness Scale*ITS and Mindful Attention Awareness Scale*SRSE, adjusting for school clustering effects and covariates. Both interaction terms were significant in cross-sectional analyses and showed that high ITS predicted higher smoking frequency among those low, relative to high, in trait mindfulness, whereas low SRSE predicted higher smoking frequency among those low, relative to high, in trait mindfulness. Findings suggest trait mindfulness possibly shields against decision-making processes that place adolescents at risk for smoking. Copyright © 2012 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

Cell–scaffold interaction within engineered tissue

Energy Technology Data Exchange (ETDEWEB)

Chen, Haiping; Liu, Yuanyuan, E-mail: Yuanyuan_liu@shu.edu.cn; Jiang, Zhenglong; Chen, Weihua; Yu, Yongzhe; Hu, Qingxi

2014-05-01

The structure of a tissue engineering scaffold plays an important role in modulating tissue growth. A novel gelatin–chitosan (Gel–Cs) scaffold with a unique structure produced by three-dimensional printing (3DP) technology combining with vacuum freeze-drying has been developed for tissue-engineering applications. The scaffold composed of overall construction, micro-pore, surface morphology, and effective mechanical property. Such a structure meets the essential design criteria of an ideal engineered scaffold. The favorable cell–matrix interaction supports the active biocompatibility of the structure. The structure is capable of supporting cell attachment and proliferation. Cells seeded into this structure tend to maintain phenotypic shape and secreted large amounts of extracellular matrix (ECM) and the cell growth decreased the mechanical properties of scaffold. This novel biodegradable scaffold has potential applications for tissue engineering based upon its unique structure, which acts to support cell growth. - Highlights: • The scaffold is not only for providing a surface for cell residence but also for determining cell phenotype and retaining structural integrity. • The mechanical property of scaffold can be affected by activities of cell. • The scaffold provides a microenvironment for cell attachment, growth, and migration.

Brief Mindfulness Meditation Training Reduces Mind-Wandering: The Critical Role of Acceptance

Science.gov (United States)

Rahl, Hayley A.; Lindsay, Emily K.; Pacilio, Laura E.; Brown, Kirk W.; Creswell, J. David

2016-01-01

Mindfulness meditation programs, which train individuals to monitor their present moment experience in an open or accepting way, have been shown to reduce mind-wandering on standardized tasks in several studies. Here we test two competing accounts for how mindfulness training reduces mind-wandering, evaluating whether the attention monitoring component of mindfulness training alone reduces mind-wandering or whether the acceptance training component is necessary for reducing mind-wandering. Healthy young adults (N=147) were randomized to either a 3-day brief mindfulness training condition incorporating instruction in both attention monitoring and acceptance, a mindfulness training condition incorporating attention monitoring instruction only, a relaxation training condition, or a reading control condition. Participants completed measures of dispositional mindfulness and treatment expectancies before the training session on Day 1 and then completed a 6-minute Sustained Attention Response Task (SART) measuring mind-wandering after the training session on Day 3. Acceptance training was important for reducing mind-wandering, such that the monitoring + acceptance mindfulness training condition had the lowest mind-wandering relative to the other conditions, including significantly lower mind-wandering relative to the monitor-only mindfulness training condition. In one of the first experimental mindfulness training dismantling studies to-date, we show that training in acceptance is a critical driver of mindfulness training reductions in mind-wandering. This effect suggests that acceptance skills may facilitate emotion regulation on boring and frustrating sustained attention tasks that foster mind-wandering, such as the SART. PMID:27819445

Using Scaffolds in Problem-Based Hypermedia

Science.gov (United States)

Su, Yuyan; Klein, James D.

2010-01-01

This study investigated the use of scaffolds in problem-based hypermedia. Three hundred and twelve undergraduate students enrolled in a computer literacy course worked in project teams to use a hypermedia PBL program focused on designing a personal computer. The PBL program included content scaffolds, metacognitive scaffolds, or no scaffolds.…

Injectable porous nano-hydroxyapatite/chitosan/tripolyphosphate scaffolds with improved compressive strength for bone regeneration

Energy Technology Data Exchange (ETDEWEB)

Uswatta, Suren P.; Okeke, Israel U. [Department of Bioengineering, The University of Toledo, Toledo, OH 43614 (United States); Jayasuriya, Ambalangodage C., E-mail: a.jayasuriya@utoledo.edu [Department of Bioengineering, The University of Toledo, Toledo, OH 43614 (United States); Department of Orthopaedic Surgery, The University of Toledo, Toledo, OH 43614 (United States)

2016-12-01

studies. 2% nHA/chitosan scaffolds showed higher osteoblast attachment than 0% nHA/chitosan scaffolds. - Highlights: • Injectable porous scaffolds prepared from chitosan and nano-hydroxyapatite. • Scaffolds are fabricated using non-toxic coacervation and lyophilization techniques. • 2% nHA/chitosan scaffolds exhibited the highest ultimate compressive strength. • Scaffolds' compressive strength can be increased by simple soaking and drying. • Scaffolds showed very good osteoblast adhesion and proliferation.

Injectable porous nano-hydroxyapatite/chitosan/tripolyphosphate scaffolds with improved compressive strength for bone regeneration

International Nuclear Information System (INIS)

Uswatta, Suren P.; Okeke, Israel U.; Jayasuriya, Ambalangodage C.

2016-01-01

studies. 2% nHA/chitosan scaffolds showed higher osteoblast attachment than 0% nHA/chitosan scaffolds. - Highlights: • Injectable porous scaffolds prepared from chitosan and nano-hydroxyapatite. • Scaffolds are fabricated using non-toxic coacervation and lyophilization techniques. • 2% nHA/chitosan scaffolds exhibited the highest ultimate compressive strength. • Scaffolds' compressive strength can be increased by simple soaking and drying. • Scaffolds showed very good osteoblast adhesion and proliferation.

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

Preparation, characterization and biological test of 3D-scaffolds based on chitosan, fibroin and hydroxyapatite for bone tissue engineering

International Nuclear Information System (INIS)

Lima, Paulo Autran Leite; Resende, Cristiane Xavier; Dulce de Almeida Soares, Glória; Anselme, Karine; Almeida, Luís Eduardo

2013-01-01

This work describes the preparation and characterization of porous 3D-scaffolds based on chitosan (CHI), chitosan/silk fibroin (CHI/SF) and chitosan/silk fibroin/hydroxyapatite (CHI/SF/HA) by freeze drying. The biomaterials were characterized by X-ray diffraction, attenuated total reflection Fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, scanning electron microscopy and energy dispersive spectroscopy. In addition, studies of porosity, pore size, contact angle and biological response of SaOs-2osteoblastic cells were performed. The CHI scaffolds have a porosity of 94.2 ± 0.9%, which is statistically higher than the one presented by CHI/SF/HA scaffolds, 89.7 ± 2.6%. Although all scaffolds were able to promote adhesion, growth and maintenance of osteogenic differentiation of SaOs-2 cells, the new 3D-scaffold based on CHI/SF/HA showed a significantly higher cell growth at 7 days and 21 days and the level of alkaline phosphatase at 14 and 21 days was statistically superior compared to other tested materials. - Highlights: • Preparation of 3D-scaffolds based on CHI, with or without addition of SF and HA. • Scaffolds exhibited interconnected porous structure (pore size superior to 50 μm). • The tripolyphosphate did not induce any significant cytotoxic response. • The CHI/SF/HA composite showed a higher cell growth and ALP activity

Bioactive polymeric scaffolds for tissue engineering

Directory of Open Access Journals (Sweden)

Scott Stratton

2016-12-01

Full Text Available A variety of engineered scaffolds have been created for tissue engineering using polymers, ceramics and their composites. Biomimicry has been adopted for majority of the three-dimensional (3D scaffold design both in terms of physicochemical properties, as well as bioactivity for superior tissue regeneration. Scaffolds fabricated via salt leaching, particle sintering, hydrogels and lithography have been successful in promoting cell growth in vitro and tissue regeneration in vivo. Scaffold systems derived from decellularization of whole organs or tissues has been popular due to their assured biocompatibility and bioactivity. Traditional scaffold fabrication techniques often failed to create intricate structures with greater resolution, not reproducible and involved multiple steps. The 3D printing technology overcome several limitations of the traditional techniques and made it easier to adopt several thermoplastics and hydrogels to create micro-nanostructured scaffolds and devices for tissue engineering and drug delivery. This review highlights scaffold fabrication methodologies with a focus on optimizing scaffold performance through the matrix pores, bioactivity and degradation rate to enable tissue regeneration. Review highlights few examples of bioactive scaffold mediated nerve, muscle, tendon/ligament and bone regeneration. Regardless of the efforts required for optimization, a shift in 3D scaffold uses from the laboratory into everyday life is expected in the near future as some of the methods discussed in this review become more streamlined.

Fabrication and characterization of electrospun osteon mimicking scaffolds for bone tissue engineering

Energy Technology Data Exchange (ETDEWEB)

Andric, T. [Virginia Tech-Wake Forest School of Biomedical Engineering and Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061 (United States); Sampson, A.C. [Chemical Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061 (United States); Freeman, J.W., E-mail: jwfreeman@vt.edu [Virginia Tech-Wake Forest School of Biomedical Engineering and Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061 (United States)

2011-01-01

Skeletal loss and bone deficiencies are a major worldwide problem with over 600,000 procedures performed in the US alone annually, making bone one of the most transplanted tissues, second to blood only. Bone is a composite tissue composed of organic matrix, inorganic bone mineral, and water. Structurally bone is organized into two distinct types: trabecular (or cancellous) and cortical (or compact) bones. Trabecular bone is characterized by an extensive interconnected network of pores. Cortical bone is composed of tightly packed units, called osteons, oriented parallel along to the axis of the bone. While the majority of scaffolds attempt to replicate the structure of the trabecular bone, fewer attempts have been made to create scaffolds to mimic the structure of cortical bone. The aim of this study was to develop a technique to fabricate scaffolds that mimic the organization of an osteon, the structural unit of cortical bone. We successfully built a rotating stage for PGA fibers and utilized it for collecting electrospun nanofibers and creating scaffolds. Resulting scaffolds consisted of concentric layers of electrospun PLLA or gelatin/PLLA nanofibers wrapped around PGA microfiber core with diameters that ranged from 200 to 600 {mu}m. Scaffolds were mineralized by incubation in 10x simulated body fluid, and scaffolds composed of 10%gelatin/PLLA had significantly higher amounts of calcium phosphate. The electrospun scaffolds also supported cellular attachment and proliferation of MC3T3 cells over the period of 28 days.

Development of an electrospun biomimetic polyurea scaffold suitable for vascular grafting.

Science.gov (United States)

Madhavan, Krishna; Frid, Maria G; Hunter, Kendall; Shandas, Robin; Stenmark, Kurt R; Park, Daewon

2018-01-01

The optimization of biomechanical and biochemical properties of a vascular graft to render properties relevant to physiological environments is a major challenge today. These critical properties of a vascular graft not only regulate its stability and integrity, but also control invasion of cells for scaffold remodeling permitting its integration with native tissue. In this work, we have synthesized a biomimetic scaffold by electrospinning a blend of a polyurea, poly(serinol hexamethylene urea) (PSHU), and, a polyester, poly-ε-caprolactone (PCL). Mechanical properties of the scaffold were varied by varying polymer blending ratio and electrospinning flow rate. Mechanical characterization revealed that scaffolds with lower PSHU content relative to PCL content resulted in elasticity close to native mammalian arteries. We also found that increasing electrospinning flow rates also increased the elasticity of the matrix. Optimization of elasticity generated scaffolds that enabled vascular smooth muscle cells (SMCs) to adhere, grow and maintain a SMC phenotype. The 30/70 scaffold also underwent slower degradation than scaffolds with higher PSHU content, thereby, providing the best option for in vivo remodeling. Further, Gly-Arg-Gly-Asp-Ser (RGD) covalently conjugated to the polyurea backbone in 30/70 scaffold resulted in significantly increased clotting times. Reducing surface thrombogenicity by the conjugation of RGD is critical to avoiding intimal hyperplasia. Hence, biomechanical and biochemical properties of a vascular graft can be balanced by optimizing synthesis parameters and constituent components. For these reasons, the optimized RGD-conjugated 30/70 scaffold electrospun at 2.5 or 5 mL/h has great potential as a suitable material for vascular grafting applications. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 278-290, 2018. © 2017 Wiley Periodicals, Inc.

The Bisphosphonate Clodronate Modifying Hydroxyapatite Bioceramics for Bone Scaffold

Institute of Scientific and Technical Information of China (English)

无

2005-01-01

To investigate the efficiency of clodronate modifying HA bioceramics , and to evaluate the effect of clodronate modifying HA bioceramies on the cells in vitro, clodronate modified the porous HA bioceramics for bone scaffold by chelation. The outermost layer of the specimens was analyzed by XPS and FI- IR. The depth profile was investigated by the argon-ion sputtering method. The cell culture test was conducted using MC3 T3-E1 osteoblastic cells. The cells were inoculated and cultured on the scaffolds. Morphological observation of the cells,MTT test and ALP activity test evaluated the cell attachment, proliferation and activity on the materials. Characteristic peaks in XPS and FT-IR spectra indicated clodronate being immobilized on the surface of the bioceramics.The cell culture test in cell quantity and morphology indicated active proliferation of the cells on the scaffolds. The ALP activity of the cells cultured for 3d and 7 d on clodronate- HA bioceramics was slightly higher than that on HA bioceramics, but the difference was not significant. This result indicated that clodronate- HA bioceramics had favorable cytocompatibility to be used as bone scaffold with potential ability to improve osteogenesis.

Manufacture of β-TCP/alginate scaffolds through a Fab@home model for application in bone tissue engineering

International Nuclear Information System (INIS)

Diogo, G S; Gaspar, V M; Serra, I R; Fradique, R; Correia, I J

2014-01-01

The growing need to treat bone-related diseases in an elderly population compels the development of novel bone substitutes to improve patient quality of life. In this context, the advent of affordable and effective rapid prototyping equipment, such as the Fab@home plotter, has contributed to the development of novel scaffolds for bone tissue engineering. In this study, we report for the first time the use of a Fab@home plotter for the production of 3D scaffolds composed by beta-tricalcium phosphate (β-TCP)/alginate hybrid materials. β-TCP/alginate mixtures were used in a proportion of 50/50% (w/w), 30/70% (w/w) and 20/80% (w/w). The printing parameters were optimized to a nozzle diameter of 20 Gauge for the production of rigid scaffolds with pre-defined architectures. We observed that, despite using similar printing parameters, both the precision and resolution of the scaffolds were significantly affected by the blend's viscosity. In particular, we demonstrate that the higher viscosity of 50/50 scaffolds (150.0 ± 3.91 mPa s) provides a higher precision in the extrusion process. The physicochemical and biological characterization of the samples demonstrated that the 50/50 scaffolds possessed a resistance to compression comparable to that of native trabecular bone. Moreover, this particular formulation also exhibited a Young's modulus that was higher than that of trabecular bone. Scanning electron microscopy and fluorescence microscopy analysis revealed that osteoblasts were able to adhere, proliferate and also penetrate into the scaffold's architecture. Altogether, our findings suggest that the Fab@home printer can be employed in the manufacture of reproducible scaffolds, using a formulation 50/50 alginate-β-TCP that has suitable properties to be applied as bone substitutes in the future. (paper)

Anisotropic Shape-Memory Alginate Scaffolds Functionalized with Either Type I or Type II Collagen for Cartilage Tissue Engineering.

Science.gov (United States)

Almeida, Henrique V; Sathy, Binulal N; Dudurych, Ivan; Buckley, Conor T; O'Brien, Fergal J; Kelly, Daniel J

2017-01-01

Regenerating articular cartilage and fibrocartilaginous tissue such as the meniscus is still a challenge in orthopedic medicine. While a range of different scaffolds have been developed for joint repair, none have facilitated the development of a tissue that mimics the complexity of soft tissues such as articular cartilage. Furthermore, many of these scaffolds are not designed to function in mechanically challenging joint environments. The overall goal of this study was to develop a porous, biomimetic, shape-memory alginate scaffold for directing cartilage regeneration. To this end, a scaffold was designed with architectural cues to guide cellular and neo-tissue alignment, which was additionally functionalized with a range of extracellular matrix cues to direct stem cell differentiation toward the chondrogenic lineage. Shape-memory properties were introduced by covalent cross-linking alginate using carbodiimide chemistry, while the architecture of the scaffold was modified using a directional freezing technique. Introducing such an aligned pore structure was found to improve the mechanical properties of the scaffold, and promoted higher levels of sulfated glycosaminoglycans (sGAG) and collagen deposition compared to an isotropic (nonaligned) pore geometry when seeded with adult human stem cells. Functionalization with collagen improved stem cell recruitment into the scaffold and facilitated more homogenous cartilage tissue deposition throughout the construct. Incorporating type II collagen into the scaffolds led to greater cell proliferation, higher sGAG and collagen accumulation, and the development of a stiffer tissue compared to scaffolds functionalized with type I collagen. The results of this study demonstrate how both scaffold architecture and composition can be tailored in a shape-memory alginate scaffold to direct stem cell differentiation and support the development of complex cartilaginous tissues.

Mindfulness Is Associated With Treatment Response From Nonpharmacologic Exercise Interventions in Knee Osteoarthritis.

Science.gov (United States)

Lee, Augustine C; Harvey, William F; Price, Lori Lyn; Han, Xingyi; Driban, Jeffrey B; Wong, John B; Chung, Mei; McAlindon, Timothy E; Wang, Chenchen

2017-11-01

To examine the association between baseline mindfulness and response from exercise interventions in knee osteoarthritis (OA). Cohort study; responder analysis of a clinical trial subset. Urban tertiary care academic hospital. Participants with symptomatic, radiographic knee OA (N=86; mean age, 60y; 74% female; 48% white). Twelve weeks (twice per week) of Tai Chi or physical therapy exercise. Treatment response was defined using Osteoarthritis Research Society International criteria indicating meaningful improvements in the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain, WOMAC function, or Patient Global Assessment scores. At baseline, participants completed the Five Facet Mindfulness Questionnaire (mean total score, 142±17) and were grouped into 3 categories of total mindfulness: higher, medium, or lower. Relative risk (RR) ratios were used to compare treatment response across groups. Participants with higher total mindfulness were 38% (95% confidence interval [CI], 1.05-1.83) more likely to meet responder criteria than those with lower mindfulness. We found no significant difference between medium and lower mindfulness groups (RR=1.0; 95% CI, 0.69-1.44). Among the 5 mindfulness facets, medium acting-with-awareness was 46% (95% CI, 1.09-1.96) more likely to respond than lower acting-with-awareness, and higher acting-with-awareness was 34% more likely to respond, but this did not reach significance (95% CI, 0.97-1.86). In this study, higher mindfulness, primarily driven by its acting-with-awareness facet, was significantly associated with a greater likelihood of response to nonpharmacologic exercise interventions in knee OA. This suggests that mindfulness-cultivating interventions may increase the likelihood of response from exercise. Copyright © 2017 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Aligned and random nanofibrous nanocomposite scaffolds for bone tissue engineering

Directory of Open Access Journals (Sweden)

Amir Doustgani

2013-01-01

Full Text Available Abstract  Aligned and random nanocomposite nanofibrous scaffolds were electrospun from polycaprolactone (PCL, poly (vinyl alcohol (PVA and hydroxyapatite nanoparticles (nHA. The morphology and mechanical characteristics of the nanofibers were evaluated using scanning electron microscopy and tensile testing, respectively. Scanning electron microscopy revealed fibers with an average diameter of 123 ± 32 nm and 339 ± 107 nm for aligned and random nanofibers, respectively. The mechanical data indicated the higher tensile strength and elastic modulus of aligned nanofibers. The in vitro biocompatibility of aligned and random nanofibrous scaffolds was also assessed by growing mesenchymal stem cells (MSCs, and investigating the proliferation and alkaline phosphatase activity (ALP on different nanofibrous scaffolds. Our  findings  showed  that  the  alignment  orientation  of  nanofibers  enhanced  the osteogenic differentiation of stem cells. The in vitro results showed that the aligned biocomposite nanofibrous scaffolds of PCL/nHA/PVA could be a potential substrate for tissue engineering applications, especially in the field of artificial bone implant.

Towards an ideal polymer scaffold for tendon/ligament tissue engineering

Science.gov (United States)

Sahoo, Sambit; Ouyang, Hong Wei; Goh, James Cho-Hong; Tay, Tong-Earn; Toh, Siew Lok

2005-04-01

Tissue engineering holds promise in treating injured tendons and ligaments by replacing the injured tissues with "engineered tissues" with identical mechanical and functional characteristics. A biocompatible, biodegradable, porous scaffold with optimized architecture, sufficient surface area for cell attachment, growth and proliferation, faborable mechanical properties, and suitable degradation rate is a pre-requisite to achieve success with this aproach. Knitted poly(lactide-co-glycolide) (PLGA) scaffolds comprising of microfibers of 25 micron diameter were coated with PLGA nanofibers on their surfaces by electrospinning technique. A cell suspension of pig bone marrow stromal cells (BMSC) was seeded on the scaffolds by pipetting, and the cell-scaffold constructs were cultured in a CO2 incubator, at 37°C for 1-2 weeks. The "engineered tissues" were then assessed for cell attachment and proliferation, tissue formation, and mechanical properties. Nanofibers, of diameter 300-900 nm, were spread randomly over the knitted scaffold. The reduction in pore-size from about 1 mm (in the knitted scaffold) to a few micrometers (in the nano-microscaffold) allowed cell seeding by direct pipetting, and eliminated the need of a cell-delivery system like fibrin gel. BMSCs were seen to attach and proliferate well on the nano-microscaffold, producing abundant extracellular matrix. Mechanical testing revealed that the cell-seeded nano-microscaffolds possessed slightly higher values of failure load, elastic-region stiffness and toe-region stiffness, than the unseeded scaffolds. The combination of superior mechanical strength and integrity of knitted microfibers, with the large surface area and improved hydrophilicity of the electrospun nanofibers facilitated cell attachment and new tissue formation. This holds promise in tissue engineering of tendon/ligament.

Bone Morphogenic Protein-2 (rhBMP2)-Loaded Silk Fibroin Scaffolds to Enhance the Osteoinductivity in Bone Tissue Engineering

Science.gov (United States)

Du, Guang-Yu; He, Sheng-Wei; Sun, Chuan-Xiu; Mi, Li-Dong

2017-10-01

There is an increasing demand for formulations of silk fibroin (SF) scaffolds in biomedical applications. SF was crosslinked via glutaraldehyde with osteoinductive recombinant human bone morphogenic protein-2 (rhBMP2) of different ratios viz. (i) 3% SF with no rhBMP2 (SF), (ii) 3% SF with equal amount of rhBMP2 (SF+BMP2), and (iii) 12% SF with 3% of rhBMP2 (4SF+BMP2), and these solutions were used in electrospinning-based fabrication of nanoscaffolds for evaluating increased osteoinductive potential of SF scaffolds with rhBMP2. Stress-strain relationship suggested there is no loss in mechanical strength of fibers with addition of rhBMP2, and mechanical strength of scaffold was improved with increase in concentration of SF. rhBMP2 association increased the water retention capacity of scaffold as evident from swelling studies. Viability of hMSCs was found to be higher in conjugated scaffolds, and scaffolds do not exhibit any cytotoxicity towards guest cells. Cells were found to have higher alkaline phosphatase activity in conjugated scaffolds under in vitro and in vivo conditions which establishes the increased osteoinductivity of the novel construct. The scaffolds were found to be effective for in vivo bone formation as well.

Preparation and characterization of biohybrid poly (3-hydroxybutyrate-co-3-hydroxyvalerate) based nanofibrous scaffolds

Science.gov (United States)

Kouhi, Monireh; Fathi, Mohammadhossein; Venugopal, Jayarama Reddy; Shamanian, Morteza; Ramakrishna, Seeram

2018-01-01

Development of bioengineered scaffolds for bone tissue regeneration is a growing area of research, especially those involving biodegradable electrospun nanofibers incorporated with ceramic nanoparticles, since they can mimic the extracellular matrix (ECM) of the native bone. In the current study, a biocomposite nanofibrous scaffolds consisting of poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), fibrinogen (FIB) and bredigite (BR) nanoparticles was fabricated through electrospinning. The morphological, chemical and mechanical characteristics of the resultant scaffolds were studied by using field emission-scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR) and tensile tester, respectively. It was found that PHBV-FIB-BR scaffolds exhibited enhanced tensile strength and young modulus compared to PHBV and PHBV-FIB scaffolds. In addition, the measurements of the water contact angle suggested that incorporation of bredigite and fibrinogen into PHBV could improve the hydrophilicity of the composites. The results of bioactivity assessment performed in the simulated body fluid (SBF) demonstrated that the presence of the bredigite nanoparticles induced the nucleation and growth of apatite layer on the surface of PHBV-FIB-BR scaffold in SBF. Furthermore, the ion concentration changes of SBF solutions with composite scaffolds showed that PHBV-FIB-BR scaffolds released Ca and Si ions, which can stimulate osteoblast proliferation. The results of cell culture studies revealed the higher osteoblast proliferation, mineralization and differentiation on PHBV-FIB-BR and PHBV-FIB scaffolds than on PHBV. Our results suggest that PHBV-FIB-BR nanofibrous scaffold would be a promising candidate as a biocomposite nanofibrous scaffold material for tissue engineering applications.

Morphological Effects of HA on the Cell Compatibility of Electrospun HA/PLGA Composite Nanofiber Scaffolds

Directory of Open Access Journals (Sweden)

Adnan Haider

2014-01-01

Full Text Available Tissue engineering is faced with an uphill challenge to design a platform with appropriate topography and suitable surface chemistry, which could encourage desired cellular activities and guide bone tissue regeneration. To develop such scaffolds, composite nanofiber scaffolds of nHA and sHA with PLGA were fabricated using electrospinning technique. nHA was synthesized using precipitation method, whereas sHA was purchased. The nHA and sHA were suspended in PLGA solution separately and electrospun at optimized electrospinning parameters. The composite nanofiber scaffolds were characterized by FE-SEM, EDX analysis, TEM, XRD analysis, FTIR, and X-ray photoelectron. The potential of the HA/PLGA composite nanofiber as bone scaffolds in terms of their bioactivity and biocompatibility was assessed by culturing the osteoblastic cells onto the composite nanofiber scaffolds. The results from in vitro studies revealed that the nHA/PLGA composite nanofiber scaffolds showed higher cellular adhesion, proliferation, and enhanced osteogenesis performance, along with increased Ca+2 ions release compared to the sHA/PLGA composite nanofiber scaffolds and pristine PLGA nanofiber scaffold. The results show that the structural dependent property of HA might affect its potential as bone scaffold and implantable materials in regenerative medicine and clinical tissue engineering.

Coating of hydrophobins on three-dimensional electrospun poly(lactic-co-glycolic acid) scaffolds for cell adhesion

Energy Technology Data Exchange (ETDEWEB)

Hou Sen; Li Xinxin; Li Xiaoyu; Feng Xizeng, E-mail: xzfeng@nankai.edu.c [College of Life Science, Nankai University, Weijin Road 94, Tianjin, 300071 (China)

2009-09-15

Surface modification with hydrophobins is very important for cell adhesion in its applications in biosensor fabrication. In this study, we modified the surface of three-dimensional electrospun poly(lactide-co-glycolide) (PLGA) scaffolds with hydrophobin HFBI and collagen, and investigated its applications for cell adhesion. We found that HFBI could not only improve the hydrophilicity of the three-dimensional electrospun PLGA scaffolds but also endow the electrospun PLGA scaffolds with water permeability. This permeability should be attributed to both the hydrophilicity of the modified PLGA surface and the large positive capillary effect induced by the microstructures. Further experiment indicated that HFBI modification could improve collagen immobilization on the electrospun PLGA scaffolds and the HFBI/collagen modified electrospun PLGA scaffolds showed higher efficiency in promoting cell adhesion than the native PLGA scaffolds. This finding should be of potential application in biosensor device fabrication.

Poly (L-lactic acid) porous scaffold-supported alginate hydrogel with improved mechanical properties and biocompatibility.

Science.gov (United States)

Chu, Jiaqi; Zeng, Shaodong; Gao, Liyang; Groth, Thomas; Li, Zhiwen; Kong, Junchao; Zhao, Mingyan; Li, Lihua

2016-10-10

Polymer porous scaffolds and hydrogels have been separately employed and explored for a wide range of applications including cell encapsulation, drug delivery, and tissue engineering. In this study, a three-dimensional poly (L-lactic acid) (PLLA) scaffold with interconnected and homogeneously distributed pores was fabricated to support the alginate hydrogel (Alg). The gels were filled into the porous scaffold, which acted as an analogue of native extracellular matrix (ECM) for entrapment of cells within a support of predefined shape. The mechanical strength of the composite scaffold was characterized by compression testing. The chondrocyte behavior in the scaffold was determined by inverted microscopy, scanning electron microscopy (SEM) and MTT viability assay. The repair efficiency of such a composite scaffold was further investigated in dog spinal defects by histological evaluation after implantation for 4 weeks. Results showed that the composite scaffold possessed superior mechanical properties and hierarchical porous structure in comparison to pure Alg. Cell culture revealed that the cells presented a specific cartilage status in the composite scaffold in line with higher adherence and proliferation ratio. The histological analyses suggested that the composite scaffold substantially promotes its integration in the host tissue accompanied with a low inflammatory reaction and new tissue formation. The method thus provides a useful pathway for scaffold preparation that can simultaneously achieve suitable mechanical properties and good biocompatibility.

Preparation and Evaluation of Gelatin-Chitosan-Nanobioglass 3D Porous Scaffold for Bone Tissue Engineering

Directory of Open Access Journals (Sweden)

Kanchan Maji

2016-01-01

Full Text Available The aim of the present study was to prepare and characterize bioglass-natural biopolymer based composite scaffold and evaluate its bone regeneration ability. Bioactive glass nanoparticles (58S in the size range of 20–30 nm were synthesized using sol-gel method. Porous scaffolds with varying bioglass composition from 10 to 30 wt% in chitosan, gelatin matrix were fabricated using the method of freeze drying of its slurry at 40 wt% solids loading. Samples were cross-linked with glutaraldehyde to obtain interconnected porous 3D microstructure with improved mechanical strength. The prepared scaffolds exhibited >80% porosity with a mean pore size range between 100 and 300 microns. Scaffold containing 30 wt% bioglass (GCB 30 showed a maximum compressive strength of 2.2±0.1 MPa. Swelling and degradation studies showed that the scaffold had excellent properties of hydrophilicity and biodegradability. GCB 30 scaffold was shown to be noncytotoxic and supported mesenchymal stem cell attachment, proliferation, and differentiation as indicated by MTT assay and RUNX-2 expression. Higher cellular activity was observed in GCB 30 scaffold as compared to GCB 0 scaffold suggesting the fact that 58S bioglass nanoparticles addition into the scaffold promoted better cell adhesion, proliferation, and differentiation. Thus, the study showed that the developed composite scaffolds are potential candidates for regenerating damaged bone tissue.

Development of novel hybrid poly(l-lactide)/chitosan scaffolds using the rapid freeze prototyping technique

Energy Technology Data Exchange (ETDEWEB)

Zhu, N; Chen, X B [Division of Biomedical Engineering, University of Saskatchewan, Saskatoon, Saskatchewan (Canada); Li, M G [Department of Mechanical Engineering, University of Saskatchewan, Saskatoon, Saskatchewan (Canada); Cooper, D, E-mail: xbc719@mail.usask.ca [Department of Anatomy and Cell Biology, University of Saskatchewan, Saskatoon, Saskatchewan (Canada)

2011-09-15

Engineered scaffolds have been shown to be critical to various tissue engineering applications. This paper presents the development of a novel three-dimensional scaffold made from a mixture of chitosan microspheres (CMs) and poly(l-lactide) by means of the rapid freeze prototyping (RFP) technique. The CMs were used to encapsulate bovine serum albumin (BSA) and improve the scaffold mechanical properties. Experiments to examine the BSA release were carried out; the BSA release could be controlled by adjusting the crosslink degree of the CMs and prolonged after the CMs were embedded into the PLLA scaffolds, while the examination of the mechanical properties of the scaffolds illustrates that they depend on the ratio of CMs to PLLA in the scaffolds as well as the cryogenic temperature used in the RFP fabrication process. The chemical characteristics of the PLLA/chitosan scaffolds were evaluated by Fourier transform infrared (FTIR) spectroscopy. The morphological and pore structure of the scaffolds were also examined by scanning electron microscopy and micro-tomography. The results obtained show that the scaffolds have higher porosity and enhanced pore size distribution compared to those fabricated by the dispensing-based rapid prototyping technique. This study demonstrates that the novel scaffolds have not only enhanced porous structure and mechanical properties but also showed the potential to preserve the bioactivities of the biomolecules and to control the biomolecule distribution and release rate.

SHOP: scaffold hopping by GRID-based similarity searches

DEFF Research Database (Denmark)

Bergmann, Rikke; Linusson, Anna; Zamora, Ismael

2007-01-01

A new GRID-based method for scaffold hopping (SHOP) is presented. In a fully automatic manner, scaffolds were identified in a database based on three types of 3D-descriptors. SHOP's ability to recover scaffolds was assessed and validated by searching a database spiked with fragments of known...... scaffolds were in the 31 top-ranked scaffolds. SHOP also identified new scaffolds with substantially different chemotypes from the queries. Docking analysis indicated that the new scaffolds would have similar binding modes to those of the respective query scaffolds observed in X-ray structures...

Alginate based scaffolds for bone tissue engineering

Energy Technology Data Exchange (ETDEWEB)

Valente, J.F.A.; Valente, T.A.M. [CICS-UBI - Centro de Investigacao em Ciencias da Saude, Faculdade de Ciencias da Saude, Universidade da Beira Interior, Covilha (Portugal); Alves, P.; Ferreira, P. [CIEPQPF, Departamento de Engenharia Quimica, Universidade de Coimbra, Polo II, Pinhal de Marrocos, 3030-290 Coimbra (Portugal); Silva, A. [Centro de Ciencia e Tecnologia Aeroespaciais, Universidade da Beira Interior, Covilha (Portugal); Correia, I.J., E-mail: icorreia@ubi.pt [CICS-UBI - Centro de Investigacao em Ciencias da Saude, Faculdade de Ciencias da Saude, Universidade da Beira Interior, Covilha (Portugal)

2012-12-01

The design and production of scaffolds for bone tissue regeneration is yet unable to completely reproduce the native bone properties. In the present study new alginate microparticle and microfiber aggregated scaffolds were produced to be applied in this area of regenerative medicine. The scaffolds' mechanical properties were characterized by thermo mechanical assays. Their morphological characteristics were evaluated by isothermal nitrogen adsorption and scanning electron microscopy. The density of both types of scaffolds was determined by helium pycnometry and mercury intrusion porosimetry. Furthermore, scaffolds' cytotoxic profiles were evaluated in vitro by seeding human osteoblast cells in their presence. The results obtained showed that scaffolds have good mechanical and morphological properties compatible with their application as bone substitutes. Moreover, scaffold's biocompatibility was confirmed by the observation of cell adhesion and proliferation after 5 days of being seeded in their presence and by non-radioactive assays. - Highlights: Black-Right-Pointing-Pointer Design and production of scaffolds for bone tissue regeneration. Black-Right-Pointing-Pointer Microparticle and microfiber alginate scaffolds were produced through a particle aggregation technique; Black-Right-Pointing-Pointer Scaffolds' mechanically and biologically properties were characterized through in vitro studies;.

Carbon nanotubes reinforced poly(L-lactide) scaffolds fabricated by thermally induced phase separation

International Nuclear Information System (INIS)

Ma, Haiyun; Xue, Li

2015-01-01

In tissue engineering, porous nanocomposite scaffolds can potentially mimic aspects of the nanoscale architecture of the extra-cellular matrix, as well as enhance the mechanical properties required for successful weight-bearing implants. In this paper, we demonstrate that highly porous thermoplastic poly(L-lactide) nanocomposite scaffolds containing different types of functionalized multi-walled carbon nanotubes (CNTs). The nanocomposite scaffolds were manufactured by a thermally induced phase separation method. This experiment produced an uniform distribution of CNTs throughout the scaffold without obvious aggregations for funtionalized CNTs filled scaffolds by scanning electron microscope observation. The CNTs were frequently located on the pore surface, forming rough, hairy nano-textures. The pore size was reduced with the increasing of CNT loading. Parts of PLLA matrix was induced into nanofibrous structures from solid-walled state, which reduced the crystallinity of the PLLA characterized by DSC measurement. The CNT incorporation significantly improved the compression modulus of the nanocomposite scaffolds, especially the functionalized CNTs. The capacity of protein adsorption is significantly improved when the concentration of the CNTs was higher than 1.0 wt.% and the cell attachment was also enhanced by the addition of CNTs, especially N-CNT. (paper)

Micro-CT based finite element models for elastic properties of glass-ceramic scaffolds.

Science.gov (United States)

Tagliabue, Stefano; Rossi, Erica; Baino, Francesco; Vitale-Brovarone, Chiara; Gastaldi, Dario; Vena, Pasquale

2017-01-01

In this study, the mechanical properties of porous glass-ceramic scaffolds are investigated by means of three-dimensional finite element models based on micro-computed tomography (micro-CT) scan data. In particular, the quantitative relationship between the morpho-architectural features of the obtained scaffolds, such as macroscopic porosity and strut thickness, and elastic properties, is sought. The macroscopic elastic properties of the scaffolds have been obtained through numerical homogenization approaches using the mechanical characteristics of the solid walls of the scaffolds (assessed through nanoindentation) as input parameters for the numerical simulations. Anisotropic mechanical properties of the produced scaffolds have also been investigated by defining a suitable anisotropy index. A comparison with morphological data obtained through the micro-CT scans is also presented. The proposed study shows that the produced glass-ceramic scaffolds exhibited a macroscopic porosity ranging between 29% and 97% which corresponds to an average stiffness ranging between 42.4GPa and 36MPa. A quantitative estimation of the isotropy of the macroscopic elastic properties has been performed showing that the samples with higher solid fractions were those closest to an isotropic material. Copyright © 2016 Elsevier Ltd. All rights reserved.

Mindfulness for group facilitation

DEFF Research Database (Denmark)

Adriansen, Hanne Kirstine; Krohn, Simon

2014-01-01

In this paper, we argue that mindfulness techniques can be used for enhancing the outcome of group performance. The word mindfulness has different connotations in the academic literature. Broadly speaking there is ‘mindfulness without meditation’ or ‘Western’ mindfulness which involves active...... thinking and ‘Eastern’ mindfulness which refers to an open, accepting state of mind, as intended with Buddhist-inspired techniques such as meditation. In this paper, we are interested in the latter type of mindfulness and demonstrate how Eastern mindfulness techniques can be used as a tool for facilitation....... A brief introduction to the physiology and philosophy of Eastern mindfulness constitutes the basis for the arguments of the effect of mindfulness techniques. The use of mindfulness techniques for group facilitation is novel as it changes the focus from individuals’ mindfulness practice...

Development of novel electrospun nanofibrous scaffold from P. ricini and A. mylitta silk fibroin blend with improved surface and biological properties

International Nuclear Information System (INIS)

Panda, N.; Bissoyi, A.; Pramanik, K.; Biswas, A.

2015-01-01

Biomaterials that stimulate cell attachment and proliferation without any surface modification (e.g. RGD coating) provide potent and cost effective scaffold for regenerative medicine. This study assessed the physico-chemical properties and cell supportive potential of a silk fibroin blend scaffold derived from eri (Philosamia ricini) and tasar (Antheraea mylitta) silk (ET) respectively by electrospinning process. The scanning electron microscopy and transmission electron microscopy study found that the fiber diameters are in 200 to 800 nm range with flat morphology. The porosity of ET scaffold is found to be 79 ± 5% with majority of pore diameter between 2.5 to 5 nm. Similarly, Bombyx mori (BM) silk fibroin and gelatin nanofibrous scaffolds were prepared and taken as control. The ultimate tensile strength of the ET and BM scaffold are found to be 1.83 ± 0.13 MPa and 1.47 ± 0.10 MPa respectively. The measured contact angle (a measure of hydrophilicity) for ET (54.7° ± 1.8°) is found to be lower than BM (62° ± 2.3°). The ability to deposit apatite over ET is comparable to that of BM nanofibers. All the scaffolds were seeded with cord blood derived mesenchymal stem cells (hMSCs) and cultured for 14 days in vitro. The immunofluorescence study reveals enhanced cell attachment with higher metabolic activity for MSCs grown over ET than BM and gelatin. The ET scaffold also demonstrated expression of higher amount cell adhesion molecules (CD29/CD44) and higher proliferation rate than BM and gelatin as confirmed by MTT assay, DNA content estimation assay, flow cytometry study and SEM study. Overall, it may be concluded that ET scaffold may have potential in developing bone tissue grafts for clinical applications in the future. - Highlights: • We have fabricated eri–tasar blended electrospun silk fibroin nanofiber with superior surface property. • The hydrophilicity is higher than the silk fibroin nanofiber derived from Bombyx mori (BM). • The nanofibrous

Development of novel electrospun nanofibrous scaffold from P. ricini and A. mylitta silk fibroin blend with improved surface and biological properties

Energy Technology Data Exchange (ETDEWEB)

Panda, N.; Bissoyi, A.; Pramanik, K.; Biswas, A., E-mail: amitb79@gmail.com

2015-03-01

Biomaterials that stimulate cell attachment and proliferation without any surface modification (e.g. RGD coating) provide potent and cost effective scaffold for regenerative medicine. This study assessed the physico-chemical properties and cell supportive potential of a silk fibroin blend scaffold derived from eri (Philosamia ricini) and tasar (Antheraea mylitta) silk (ET) respectively by electrospinning process. The scanning electron microscopy and transmission electron microscopy study found that the fiber diameters are in 200 to 800 nm range with flat morphology. The porosity of ET scaffold is found to be 79 ± 5% with majority of pore diameter between 2.5 to 5 nm. Similarly, Bombyx mori (BM) silk fibroin and gelatin nanofibrous scaffolds were prepared and taken as control. The ultimate tensile strength of the ET and BM scaffold are found to be 1.83 ± 0.13 MPa and 1.47 ± 0.10 MPa respectively. The measured contact angle (a measure of hydrophilicity) for ET (54.7° ± 1.8°) is found to be lower than BM (62° ± 2.3°). The ability to deposit apatite over ET is comparable to that of BM nanofibers. All the scaffolds were seeded with cord blood derived mesenchymal stem cells (hMSCs) and cultured for 14 days in vitro. The immunofluorescence study reveals enhanced cell attachment with higher metabolic activity for MSCs grown over ET than BM and gelatin. The ET scaffold also demonstrated expression of higher amount cell adhesion molecules (CD29/CD44) and higher proliferation rate than BM and gelatin as confirmed by MTT assay, DNA content estimation assay, flow cytometry study and SEM study. Overall, it may be concluded that ET scaffold may have potential in developing bone tissue grafts for clinical applications in the future. - Highlights: • We have fabricated eri–tasar blended electrospun silk fibroin nanofiber with superior surface property. • The hydrophilicity is higher than the silk fibroin nanofiber derived from Bombyx mori (BM). • The nanofibrous

A longitudinal investigation of the relationship between maternal mind-mindedness and theory of mind.

Science.gov (United States)

Kirk, Elizabeth; Pine, Karen; Wheatley, Lisa; Howlett, Neil; Schulz, Joerg; Fletcher, Ben C

2015-11-01

Data are presented from a longitudinal investigation examining the relationship between maternal mind-mindedness (MM) in infancy and socio-cognitive development in childhood. We revisited children (n = 18) who had taken part in a longitudinal study as infants. MM had been assessed at 10, 12, 16, and 20 months of age. We followed up these children at 5-6 years of age to test their higher order theory of mind (ToM) (using the strange stories task). The convergent validity, temporal stability, and predictive validity of the construct of MM were examined in a longitudinal data set. The five measures of MM were not significantly correlated. Mother's production of appropriate mind-related comments (but no other measures) showed evidence of temporal stability throughout infancy. Thus, MM (as measured by appropriate mind-related comments) was confirmed as a stable construct. Children's ToM at 5-6 years of age was significantly predicted by their mother's MM up to 4 years earlier, with MM accounting for 40% of the variance of the strange stories task scores. These findings identify a relationship between MM across a protracted period of infancy and socio-cognitive development at 5-6 years of age. © 2015 The British Psychological Society.

Electrospun gelatin/poly(ε-caprolactone) fibrous scaffold modified with calcium phosphate for bone tissue engineering

Energy Technology Data Exchange (ETDEWEB)

Rajzer, Izabella, E-mail: irajzer@ath.bielsko.pl [University of Bielsko-Biala (ATH), Department of Mechanical Engineering Fundamentals, Division of Materials Engineering, Willowa 2 Street, 43-309 Bielsko-Biała (Poland); Menaszek, Elżbieta [Jagiellonian University (UJ), Collegium Medicum, Department of Cytobiology, Medyczna 9 Street, 30-068 Cracow (Poland); Kwiatkowski, Ryszard [University of Bielsko-Biala (ATH), Faculty of Materials and Environmental Sciences, Institute of Textile Engineering and Polymer Materials, Willowa 2 Street, 43-309 Bielsko-Biała (Poland); Planell, Josep A.; Castano, Oscar [Institute for Bioengineering of Catalonia (IBEC), Biomaterials for Regenerative Therapies, Baldiri Reixac 15-21, 08028 Barcelona (Spain); Polytechnic University of Catalonia (UPC), Diagonal 647, 08028 Barcelona (Spain); CIBER-BBN The Biomedical Research Networking Center in Bioengineering, Biomaterials and Nanomedicine, Barcelona (Spain)

2014-11-01

In this study gelatin (Gel) modified with calcium phosphate nanoparticles (SG5) and polycaprolactone (PCL) were used to prepare a 3D bi-layer scaffold by collecting electrospun PCL and gelatin/SG5 fibers separately in the same collector. The objective of this study was to combine the desired properties of PCL and Gel/SG5 in the same scaffold in order to enhance mineralization, thus improving the ability of the scaffold to bond to the bone tissue. The scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and the wide angle X-ray diffraction (WAXD) measurements confirmed that SG5 nanoparticles were successfully incorporated into the fibrous gelatin matrix. The composite Gel/SG5/PCL scaffold exhibited more enhanced mechanical properties than individual Gel and Gel/SG5 scaffolds. The presence of SG5 nanoparticles accelerated the nucleation and growth of apatite crystals on the surface of the composite Gel/SG5/PCL scaffold in simulated body fluid (SBF). The osteoblast response in vitro to developed electrospun scaffolds (PCL and Gel/SG5/PCL) was investigated by using normal human primary NHOst cell lines. NHOst cell culture studies showed that higher alkaline phosphatase (ALP) activity and better mineralization were obtained in the case of composite materials than in pure PCL scaffolds. The mechanically strong PCL scaffold served as a skeleton, while the Gel/SG5 fibers facilitated cell spreading and mineralization of the scaffold. - Highlights: • Bi-layer scaffolds were produced by electrospinning method. • The addition of nanoparticles enhanced the bioactivity of scaffold. • Bi-layer scaffold enhanced ALP activity and NHOst cell mineralization.

Dispositional Mindfulness Moderates the Effects of Stress among Adolescents: Rumination as a Mediator

Science.gov (United States)

Ciesla, Jeffrey A.; Reilly, Laura C.; Dickson, Kelsey S.; Emanuel, Amber S.; Updegraff, John A.

2012-01-01

Recent research has demonstrated that higher levels of mindfulness are associated with greater psychological and physical health. However, the majority of this research has been conducted with adults; research is only beginning to examine the effects of mindfulness among adolescents. Further, research into adolescent mindfulness has typically…

Developmental Scaffolding

DEFF Research Database (Denmark)

Giorgi, Franco; Bruni, Luis Emilio

2015-01-01

. Within the developmental hierarchy, each module yields an inter-level relationship that makes it possible for the scaffolding to mediate the production of selectable variations. Awide range of genetic, cellular and morphological mechanisms allows the scaffolding to integrate these modular variations...... to the complexity of sign recognition proper of a cellular community. In this semiotic perspective, the apparent goal directness of any developmental strategy should no longer be accounted for by a predetermined genetic program, but by the gradual definition of the relationships selected amongst the ones...

Modifying bone scaffold architecture in vivo with permanent magnets to facilitate fixation of magnetic scaffolds.

Science.gov (United States)

Panseri, S; Russo, A; Sartori, M; Giavaresi, G; Sandri, M; Fini, M; Maltarello, M C; Shelyakova, T; Ortolani, A; Visani, A; Dediu, V; Tampieri, A; Marcacci, M

2013-10-01

The fundamental elements of tissue regeneration are cells, biochemical signals and the three-dimensional microenvironment. In the described approach, biomineralized-collagen biomaterial functions as a scaffold and provides biochemical stimuli for tissue regeneration. In addition superparamagnetic nanoparticles were used to magnetize the biomaterials with direct nucleation on collagen fibres or impregnation techniques. Minimally invasive surgery was performed on 12 rabbits to implant cylindrical NdFeB magnets in close proximity to magnetic scaffolds within the lateral condyles of the distal femoral epiphyses. Under this static magnetic field we demonstrated, for the first time in vivo, that the ability to modify the scaffold architecture could influence tissue regeneration obtaining a well-ordered tissue. Moreover, the association between NdFeB magnet and magnetic scaffolds represents a potential technique to ensure scaffold fixation avoiding micromotion at the tissue/biomaterial interface. © 2013.

Functionally graded electrospun scaffolds with tunable mechanical properties for vascular tissue regeneration

Energy Technology Data Exchange (ETDEWEB)

Thomas, Vinoy [Center for Nanoscale Materials and Biointegration (CNMB), Department of Physics, University of Alabama at Birmingham (UAB), AL 35294 (United States); Zhang Xing [Department of Biomedical Engineering, School of Engineering, University of Alabama at Birmingham (UAB), AL 35294 (United States); Catledge, Shane A [Center for Nanoscale Materials and Biointegration (CNMB), Department of Physics, University of Alabama at Birmingham (UAB), AL 35294 (United States); Vohra, Yogesh K [Center for Nanoscale Materials and Biointegration (CNMB), Department of Physics, University of Alabama at Birmingham (UAB), AL 35294 (United States)

2007-12-15

Electrospun tubular scaffolds (4 mm inner diameter) based on bio-artificial blends of polyglyconate (Maxon (registered) ) and proteins such as gelatin and elastin having a spatially designed multilayer structure were prepared for use as vascular tissue scaffolds. Scanning electron microscopy analysis of scaffolds showed a random nanofibrous morphology with fiber diameter in the range of 200-400 nm for protein-blended Maxon, which mimics the nanoscale dimensions of collagen (50-500 nm). The scaffolds have a well interconnected pore structure and porosity up to 82%, with protein blending and multi-layering in contrast to electrospun Maxon (registered) scaffolds (67%). Fourier-transform infrared spectroscopy, x-ray diffraction and differential scanning calorimetry results confirmed the blended composition and crystallinity of fibers. Uniaxial tensile testing revealed a strength of 14.46 {+-} 0.42 MPa and a modulus of 15.44 {+-} 2.53 MPa with a failure strain of 322.5 {+-} 10% for a pure Maxon (registered) scaffold. The blending of polyglyconate with biopolymers decreased the tensile properties in general, with an exception of the tensile modulus (48.38 {+-} 2 MPa) of gelatin/Maxon mesh, which was higher than that of the pure Maxon (registered) scaffold. Trilayered tubular scaffolds of gelatin/elastin, gelatin/elastin/Maxon and gelatin/Maxon (GE-GEM-GM) that mimic the complex trilayer matrix structure of natural artery have been prepared by sequential electrospinning. Tensile testing under dry conditions revealed a tensile strength of 2.71 {+-} 0.2 MPa and a modulus of 20.4 {+-} 3 MPa with a failure strain of 140 {+-} 10%. However, GE-GEM-GM scaffolds tested under wet conditions after soaking in a phosphate buffered saline medium at 37 {sup 0}C for 24 h exhibited mechanical properties (2.5 MPa tensile strength and 9 MPa tensile modulus) comparable to those of native femoral artery.

Functionally graded electrospun scaffolds with tunable mechanical properties for vascular tissue regeneration

International Nuclear Information System (INIS)

Thomas, Vinoy; Zhang Xing; Catledge, Shane A; Vohra, Yogesh K

2007-01-01

Electrospun tubular scaffolds (4 mm inner diameter) based on bio-artificial blends of polyglyconate (Maxon (registered) ) and proteins such as gelatin and elastin having a spatially designed multilayer structure were prepared for use as vascular tissue scaffolds. Scanning electron microscopy analysis of scaffolds showed a random nanofibrous morphology with fiber diameter in the range of 200-400 nm for protein-blended Maxon, which mimics the nanoscale dimensions of collagen (50-500 nm). The scaffolds have a well interconnected pore structure and porosity up to 82%, with protein blending and multi-layering in contrast to electrospun Maxon (registered) scaffolds (67%). Fourier-transform infrared spectroscopy, x-ray diffraction and differential scanning calorimetry results confirmed the blended composition and crystallinity of fibers. Uniaxial tensile testing revealed a strength of 14.46 ± 0.42 MPa and a modulus of 15.44 ± 2.53 MPa with a failure strain of 322.5 ± 10% for a pure Maxon (registered) scaffold. The blending of polyglyconate with biopolymers decreased the tensile properties in general, with an exception of the tensile modulus (48.38 ± 2 MPa) of gelatin/Maxon mesh, which was higher than that of the pure Maxon (registered) scaffold. Trilayered tubular scaffolds of gelatin/elastin, gelatin/elastin/Maxon and gelatin/Maxon (GE-GEM-GM) that mimic the complex trilayer matrix structure of natural artery have been prepared by sequential electrospinning. Tensile testing under dry conditions revealed a tensile strength of 2.71 ± 0.2 MPa and a modulus of 20.4 ± 3 MPa with a failure strain of 140 ± 10%. However, GE-GEM-GM scaffolds tested under wet conditions after soaking in a phosphate buffered saline medium at 37 0 C for 24 h exhibited mechanical properties (2.5 MPa tensile strength and 9 MPa tensile modulus) comparable to those of native femoral artery

Porous poly(vinyl alcohol)/sepiolite bone scaffolds: Preparation, structure and mechanical properties

International Nuclear Information System (INIS)

Killeen, Derek; Frydrych, Martin; Chen Biqiong

2012-01-01

Porous poly(vinyl alcohol) (PVA)/sepiolite nanocomposite scaffolds containing 0–10 wt.% sepiolite were prepared by freeze-drying and thermally crosslinked with poly(arylic acid). The microstructure of the obtained scaffolds was characterised by scanning electron microscopy and micro-computed tomography, which showed a ribbon and ladder like interconnected structure. The incorporation of sepiolite increased the mean pore size and porosity of the PVA scaffold as well as the degree of anisotropy due to its fibrous structure. The tensile strength, modulus and energy at break of the PVA solid material that constructed the scaffold were found to improve with additions of sepiolite by up to 104%, 331% and 22% for 6 wt.% clay. Such enhancements were attributed to the strong interactions between the PVA and sepiolite, the good dispersion of sepiolite nanofibres in the matrix and the intrinsic properties of the nanofibres. However, the tensile properties of the PVA scaffold deteriorated in the presence of sepiolite because of the higher porosity, pore size and degree of anisotropy. The PVA/sepiolite nanocomposite scaffold containing 6 wt.% sepiolite was characterised by an interconnected structure, a porosity of 89.5% and a mean pore size of 79 μm and exhibited a tensile strength of 0.44 MPa and modulus of 14.9 MPa, which demonstrates potential for this type of materials to be further developed as bone scaffolds. - Highlights: ► Novel PAA-crosslinked PVA/sepiolite nanocomposite scaffolds were prepared. ► They were highly porous with interconnected structures and exhibited good mechanical properties. ► The effects of sepiolite nanofibres on structure and properties of the scaffolds were investigated. ► Sepiolite nanofibres improved the mechanical properties of the solid material significantly.

Does Personal Distress Mediate the Effect of Mindfulness on Professional Quality of Life?

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Jacky T. Thomas

2012-11-01

Full Text Available Personal distress is an aspect of the empathy construct which has been negatively associated with a range of psychological and behavioral problems. However, it is unclear whether mindfulness serves to buffer these negative relationships. This study examines direct effects and mediation effects of personal distress and mindfulness among three measures of professional quality of life: compassion fatigue, burnout, and compassion satisfaction. This model was tested using a sample of clinical social workers (n = 171. Results indicated that higher personal distress is significantly associated with higher compassion fatigue and burnout and lower compassion satisfaction, while mindfulness is significantly associated with lower compassion fatigue and burnout and higher compassion satisfaction. Mediation analyses showed significant indirect effects on all three measures of professional quality of life, with effect sizes in the small to moderate range. The indirect effects of mindfulness via the personal distress path accounted for 14-22% of the total effect of mindfulness on the three measures of professional quality of life. Implications for the education and training of social workers are discussed.

Computational Exploration of Molecular Scaffolds in Medicinal Chemistry.

Science.gov (United States)

Hu, Ye; Stumpfe, Dagmar; Bajorath, Jürgen

2016-05-12

The scaffold concept is widely applied in medicinal chemistry. Scaffolds are mostly used to represent core structures of bioactive compounds. Although the scaffold concept has limitations and is often viewed differently from a chemical and computational perspective, it has provided a basis for systematic investigations of molecular cores and building blocks, going far beyond the consideration of individual compound series. Over the past 2 decades, alternative scaffold definitions and organization schemes have been introduced and scaffolds have been studied in a variety of ways and increasingly on a large scale. Major applications of the scaffold concept include the generation of molecular hierarchies, structural classification, association of scaffolds with biological activities, and activity prediction. This contribution discusses computational approaches for scaffold generation and analysis, with emphasis on recent developments impacting medicinal chemistry. A variety of scaffold-based studies are discussed, and a perspective on scaffold methods is provided.

Medicine for the wandering mind: mind wandering in medical practice.

Science.gov (United States)

Smallwood, Jonathan; Mrazek, Michael D; Schooler, Jonathan W

2011-11-01

Mind wandering--defined as a cognitive focus on information that is unrelated to immediate sensory input or the task at hand--is a ubiquitous characteristic of the human condition. When it occurs, the integrity of a wide range of cognitive skills can be compromised. The current paper describes the phenomenon of mind wandering, explores its potential role in medical practice and considers how the education system may profitably control this ubiquitous cognitive state. We argue that because many aspects of a medical professional's work (such as fatigue and depression) maximise the mind's tendency to wander, this experience is likely to be a common occurrence in many medical situations. We then review the psychological literature on mind wandering as it relates to medical practice. Based on this review, we suggest that because mind wandering interferes with an individual's ability to integrate current events into a more general context, its occurrence may lead to downstream problems in the way that symptoms are interpreted and treated. Finally, because the experience of mind wandering is often both difficult to control and hard to recognise, it is difficult to prevent. We argue that techniques that help individuals to become more mindful have the potential to ameliorate the cost of mind wandering to the medical profession. Given the ubiquitous nature of the experience of mind wandering, the integration of mindfulness training into medical education programmes could be of general benefit to society at large. © Blackwell Publishing Ltd 2011.

A perception theory in mind-body medicine: guided imagery and mindful meditation as cross-modal adaptation.

Science.gov (United States)

Bedford, Felice L

2012-02-01

A new theory of mind-body interaction in healing is proposed based on considerations from the field of perception. It is suggested that the combined effect of visual imagery and mindful meditation on physical healing is simply another example of cross-modal adaptation in perception, much like adaptation to prism-displaced vision. It is argued that psychological interventions produce a conflict between the perceptual modalities of the immune system and vision (or touch), which leads to change in the immune system in order to realign the modalities. It is argued that mind-body interactions do not exist because of higher-order cognitive thoughts or beliefs influencing the body, but instead result from ordinary interactions between lower-level perceptual modalities that function to detect when sensory systems have made an error. The theory helps explain why certain illnesses may be more amenable to mind-body interaction, such as autoimmune conditions in which a sensory system (the immune system) has made an error. It also renders sensible erroneous changes, such as those brought about by "faith healers," as conflicts between modalities that are resolved in favor of the wrong modality. The present view provides one of very few psychological theories of how guided imagery and mindfulness meditation bring about positive physical change. Also discussed are issues of self versus non-self, pain, cancer, body schema, attention, consciousness, and, importantly, developing the concept that the immune system is a rightful perceptual modality. Recognizing mind-body healing as perceptual cross-modal adaptation implies that a century of cross-modal perception research is applicable to the immune system.

Electrospun Polyhydroxybutyrate and Poly(L-lactide-co-ε-caprolactone Composites as Nanofibrous Scaffolds

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Donraporn Daranarong

2014-01-01

Full Text Available Electrospinning can produce nanofibrous scaffolds that mimic the architecture of the extracellular matrix and support cell attachment for tissue engineering applications. In this study, fibrous membranes of polyhydroxybutyrate (PHB with various loadings of poly(L-lactide-co-ε-caprolactone (PLCL were successfully prepared by electrospinning. In comparison to PLCL scaffolds, PLCL blends with PHB exhibited more irregular fibre diameter distributions and higher average fibre diameters but there were no significant differences in pore size. PLCL/PHB scaffolds were more hydrophilic (<120° with significantly reduced tensile strength (ca. 1 MPa compared to PLCL scaffolds (150.9±2.8∘ and 5.8±0.5 MPa. Increasing PLCL loading in PHB/PLCL scaffolds significantly increased the extension at break, (4–6-fold. PLCL/PHB scaffolds supported greater adhesion and proliferation of olfactory ensheathing cells (OECs than those exhibiting asynchronous growth on culture plates. Mitochondrial activity of cells cultivated on the electrospun blended membranes was enhanced compared to those grown on PLCL and PHB scaffolds (212, 179, and 153%, resp.. Analysis showed that PLCL/PHB nanofibrous membranes promoted cell cycle progression and reduced the onset of necrosis. Thus, electrospun PLCL/PHB composites promoted adhesion and proliferation of OECs when compared to their individual PLCL and PHB components suggesting potential in the repair and engineering of nerve tissue.

Rhombicuboctahedron unit cell based scaffolds for bone regeneration: geometry optimization with a mechanobiology - driven algorithm.

Science.gov (United States)

Boccaccio, Antonio; Fiorentino, Michele; Uva, Antonio E; Laghetti, Luca N; Monno, Giuseppe

2018-02-01

In a context more and more oriented towards customized medical solutions, we propose a mechanobiology-driven algorithm to determine the optimal geometry of scaffolds for bone regeneration that is the most suited to specific boundary and loading conditions. In spite of the huge number of articles investigating different unit cells for porous biomaterials, no studies are reported in the literature that optimize the geometric parameters of such unit cells based on mechanobiological criteria. Parametric finite element models of scaffolds with rhombicuboctahedron unit cell were developed and incorporated into an optimization algorithm that combines them with a computational mechanobiological model. The algorithm perturbs iteratively the geometry of the unit cell until the best scaffold geometry is identified, i.e. the geometry that allows to maximize the formation of bone. Performances of scaffolds with rhombicuboctahedron unit cell were compared with those of other scaffolds with hexahedron unit cells. We found that scaffolds with rhombicuboctahedron unit cell are particularly suited for supporting medium-low loads, while, for higher loads, scaffolds with hexahedron unit cells are preferable. The proposed algorithm can guide the orthopaedic/surgeon in the choice of the best scaffold to be implanted in a patient-specific anatomic region. Copyright © 2017 Elsevier B.V. All rights reserved.

In Vitro Degradation of PHBV Scaffolds and nHA/PHBV Composite Scaffolds Containing Hydroxyapatite Nanoparticles for Bone Tissue Engineering

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Naznin Sultana

2012-01-01

Full Text Available This paper investigated the long-term in vitro degradation properties of scaffolds based on biodegradable polymers and osteoconductive bioceramic/polymer composite materials for the application of bone tissue engineering. The three-dimensional porous scaffolds were fabricated using emulsion-freezing/freeze-drying technique using poly(hydroxybutyrate-co-hydroxyvalerate (PHBV which is a natural biodegradable and biocompatible polymer. Nanosized hydroxyapatite (nHA particles were successfully incorporated into the PHBV scaffolds to render the scaffolds osteoconductive. The PHBV and nHA/PHBV scaffolds were systematically evaluated using various techniques in terms of mechanical strength, porosity, porous morphology, and in vitro degradation. PHBV and nHA/PHBV scaffolds degraded over time in phosphate-buffered saline at 37°C. PHBV polymer scaffolds exhibited slow molecular weight loss and weight loss in the in vitro physiological environment. Accelerated weight loss was observed in nHA incorporated PHBV composite scaffolds. An increasing trend of crystallinity was observed during the initial period of degradation time. The compressive properties decreased more than 40% after 5-month in vitro degradation. Together with interconnected pores, high porosity, suitable mechanical properties, and slow degradation profile obtained from long-term degradation studies, the PHBV scaffolds and osteoconductive nHA/PHBV composite scaffolds showed promises for bone tissue engineering application.

Manipulation of chemical composition and architecture of non-biodegradable poly(ethylene terephthalate)/chitosan fibrous scaffolds and their effects on L929 cell behavior

Energy Technology Data Exchange (ETDEWEB)

Veleirinho, Beatriz [QOPNA Research Unit, Department of Chemistry, University of Aveiro, 3810-193 Aveiro (Portugal); Berti, Fernanda V. [Integrated Technologies Laboratory, Chemical and Food Engineering Department, Federal University of Santa Catarina, 88040-900 Florianopolis (Brazil); Dias, Paulo F. [Department of Cell Biology, Embryology and Genetics, Federal University of Santa Catarina, 88040-900 Florianopolis (Brazil); Maraschin, Marcelo [Department of Plant Science, Federal University of Santa Catarina, 88040-900 Florianopolis (Brazil); Ribeiro-do-Valle, Rosa M. [Department of Pharmacology, Federal University of Santa Catarina, 88040-900 Florianopolis (Brazil); Lopes-da-Silva, Jose A., E-mail: jals@ua.pt [QOPNA Research Unit, Department of Chemistry, University of Aveiro, 3810-193 Aveiro (Portugal)

2013-01-01

Microporous, non-woven fibrous scaffolds made of poly(ethylene terephthalate) and chitosan were produced by electrospinning. Fiber morphology, diameter, pore size, and wettability were manipulated by varying the chemical composition of the electrospinning solution, i.e. chitosan concentration and molecular weight, and by post-electrospinning treatment with glutaraldehyde. In vitro studies were conducted using a fibroblast cell line toward a comprehensive understanding of how scaffolds characteristics can modulate the cell behavior, i.e. viability, adhesion, proliferation, extracellular matrix secretion, and three-dimensional colonization. Substantial differences were found as a result of scaffold morphological changes. Higher levels of adhesion, spreading, and superficial proliferation were achieved for scaffolds with smaller fiber and pore diameters while cell penetration and internal colonization were enhanced for scaffolds with larger pores. Additionally, the available area for cell adhesion, which is related to fiber and pore size, was a crucial factor for the viability of L929 cells. This paper provides significant insights for the development and optimization of electrospun scaffolds toward an improved biological performance. Highlights: Black-Right-Pointing-Pointer Hybrid PET/chitosan mats were produced by electrospinning. Black-Right-Pointing-Pointer Scaffold architecture was manipulated by changing composition of the spun solution. Black-Right-Pointing-Pointer The scaffolds showed in vitro biocompatibility to L929 cells. Black-Right-Pointing-Pointer Smaller fiber diameters and pore areas allowed for higher levels of cell adhesion and proliferation. Black-Right-Pointing-Pointer A 3D cell colonization was achieved for scaffolds with higher fiber diameters.

Manipulation of chemical composition and architecture of non-biodegradable poly(ethylene terephthalate)/chitosan fibrous scaffolds and their effects on L929 cell behavior

International Nuclear Information System (INIS)

Veleirinho, Beatriz; Berti, Fernanda V.; Dias, Paulo F.; Maraschin, Marcelo; Ribeiro-do-Valle, Rosa M.; Lopes-da-Silva, José A.

2013-01-01

Microporous, non-woven fibrous scaffolds made of poly(ethylene terephthalate) and chitosan were produced by electrospinning. Fiber morphology, diameter, pore size, and wettability were manipulated by varying the chemical composition of the electrospinning solution, i.e. chitosan concentration and molecular weight, and by post-electrospinning treatment with glutaraldehyde. In vitro studies were conducted using a fibroblast cell line toward a comprehensive understanding of how scaffolds characteristics can modulate the cell behavior, i.e. viability, adhesion, proliferation, extracellular matrix secretion, and three-dimensional colonization. Substantial differences were found as a result of scaffold morphological changes. Higher levels of adhesion, spreading, and superficial proliferation were achieved for scaffolds with smaller fiber and pore diameters while cell penetration and internal colonization were enhanced for scaffolds with larger pores. Additionally, the available area for cell adhesion, which is related to fiber and pore size, was a crucial factor for the viability of L929 cells. This paper provides significant insights for the development and optimization of electrospun scaffolds toward an improved biological performance. Highlights: ► Hybrid PET/chitosan mats were produced by electrospinning. ► Scaffold architecture was manipulated by changing composition of the spun solution. ► The scaffolds showed in vitro biocompatibility to L929 cells. ► Smaller fiber diameters and pore areas allowed for higher levels of cell adhesion and proliferation. ► A 3D cell colonization was achieved for scaffolds with higher fiber diameters.

3D polylactide-based scaffolds for studying human hepatocarcinoma processes in vitro

Science.gov (United States)

Scaffaro, Roberto; Lo Re, Giada; Rigogliuso, Salvatrice; Ghersi, Giulio

2012-08-01

We evaluated the combination of leaching techniques and melt blending of polymers and particles for the preparation of highly interconnected three-dimensional polymeric porous scaffolds for in vitro studies of human hepatocarcinoma processes. More specifically, sodium chloride and poly(ethylene glycol) (PEG) were used as water-soluble porogens to form porous and solvent-free poly(L,D-lactide) (PLA)-based scaffolds. Several characterization techniques, including porosimetry, image analysis and thermogravimetry, were combined to improve the reliability of measurements and mapping of the size, distribution and microarchitecture of pores. We also investigated the effect of processing, in PLA-based blends, on the simultaneous bulk/surface modifications and pore architectures in the scaffolds, and assessed the effects on human hepatocarcinoma viability and cell adhesion. The influence of PEG molecular weight on the scaffold morphology and cell viability and adhesion were also investigated. Morphological studies indicated that it was possible to obtain scaffolds with well-interconnected pores of assorted sizes. The analysis confirmed that SK-Hep1 cells adhered well to the polymeric support and emitted surface protrusions necessary to grow and differentiate three-dimensional systems. PEGs with higher molecular weight showed the best results in terms of cell adhesion and viability.

3D chitosan-gelatin-chondroitin porous scaffold improves osteogenic differentiation of mesenchymal stem cells

Energy Technology Data Exchange (ETDEWEB)

Machado, C B [Department of Biochemistry and Immunology, Institute of Biological Sciences, Federal University of Minas Gerais (Brazil); Ventura, J M G [Department of Ceramics and Glass Engineering, University of Aveiro (Portugal); Lemos, A F [Department of Ceramics and Glass Engineering, University of Aveiro (Portugal); Ferreira, J M F [Department of Ceramics and Glass Engineering, University of Aveiro (Portugal); Leite, M F [Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais (Brazil); Goes, A M [Department of Biochemistry and Immunology, Institute of Biological Sciences, Federal University of Minas Gerais (Brazil)

2007-06-01

A porous 3D scaffold was developed to support and enhance the differentiation process of mesenchymal stem cells (MSC) into osteoblasts in vitro. The 3D scaffold was made with chitosan, gelatin and chondroitin and it was crosslinked by EDAC. The scaffold physicochemical properties were evaluated. SEM revealed the high porosity and interconnection of pores in the scaffold; rheological measurements show that the scaffold exhibits a characteristic behavior of strong gels. The elastic modulus found in compressive tests of the crosslinked scaffold was about 50 times higher than the non-crosslinked one. After 21 days, the 3D matrix submitted to hydrolytic degradation loses above 40% of its weight. MSC were collected from rat bone marrow and seeded in chitosan-gelatin-chondroitin 3D scaffolds and in 2D culture plates as well. MSC were differentiated into osteoblasts for 21 days. Cell proliferation and alkaline phosphatase activity were followed weekly during the osteogenic process. The osteogenic differentiation of MSC was improved in 3D culture as shown by MTT assay and alkaline phosphatase activity. On the 21st day, bone markers, osteopontin and osteocalcin, were detected by the PCR analysis. This study shows that the chitosan-gelatin-chondroitin 3D structure provides a good environment for the osteogenic process and enhances cellular proliferation.

3D chitosan-gelatin-chondroitin porous scaffold improves osteogenic differentiation of mesenchymal stem cells.

Science.gov (United States)

Machado, C B; Ventura, J M G; Lemos, A F; Ferreira, J M F; Leite, M F; Goes, A M

2007-06-01

A porous 3D scaffold was developed to support and enhance the differentiation process of mesenchymal stem cells (MSC) into osteoblasts in vitro. The 3D scaffold was made with chitosan, gelatin and chondroitin and it was crosslinked by EDAC. The scaffold physicochemical properties were evaluated. SEM revealed the high porosity and interconnection of pores in the scaffold; rheological measurements show that the scaffold exhibits a characteristic behavior of strong gels. The elastic modulus found in compressive tests of the crosslinked scaffold was about 50 times higher than the non-crosslinked one. After 21 days, the 3D matrix submitted to hydrolytic degradation loses above 40% of its weight. MSC were collected from rat bone marrow and seeded in chitosan-gelatin-chondroitin 3D scaffolds and in 2D culture plates as well. MSC were differentiated into osteoblasts for 21 days. Cell proliferation and alkaline phosphatase activity were followed weekly during the osteogenic process. The osteogenic differentiation of MSC was improved in 3D culture as shown by MTT assay and alkaline phosphatase activity. On the 21st day, bone markers, osteopontin and osteocalcin, were detected by the PCR analysis. This study shows that the chitosan-gelatin-chondroitin 3D structure provides a good environment for the osteogenic process and enhances cellular proliferation.

3D chitosan-gelatin-chondroitin porous scaffold improves osteogenic differentiation of mesenchymal stem cells

International Nuclear Information System (INIS)

Machado, C B; Ventura, J M G; Lemos, A F; Ferreira, J M F; Leite, M F; Goes, A M

2007-01-01

A porous 3D scaffold was developed to support and enhance the differentiation process of mesenchymal stem cells (MSC) into osteoblasts in vitro. The 3D scaffold was made with chitosan, gelatin and chondroitin and it was crosslinked by EDAC. The scaffold physicochemical properties were evaluated. SEM revealed the high porosity and interconnection of pores in the scaffold; rheological measurements show that the scaffold exhibits a characteristic behavior of strong gels. The elastic modulus found in compressive tests of the crosslinked scaffold was about 50 times higher than the non-crosslinked one. After 21 days, the 3D matrix submitted to hydrolytic degradation loses above 40% of its weight. MSC were collected from rat bone marrow and seeded in chitosan-gelatin-chondroitin 3D scaffolds and in 2D culture plates as well. MSC were differentiated into osteoblasts for 21 days. Cell proliferation and alkaline phosphatase activity were followed weekly during the osteogenic process. The osteogenic differentiation of MSC was improved in 3D culture as shown by MTT assay and alkaline phosphatase activity. On the 21st day, bone markers, osteopontin and osteocalcin, were detected by the PCR analysis. This study shows that the chitosan-gelatin-chondroitin 3D structure provides a good environment for the osteogenic process and enhances cellular proliferation

Mind Wandering "Ahas" versus Mindful Reasoning: Alternative Routes to Creative Solutions

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Claire M Zedelius

2015-06-01

Full Text Available Based on mixed results linking both mindfulness and its opposing construct mind wandering to enhanced creativity, we predicted that the relationship between mindfulness and creativity might depend on whether creative problems are approached through analytic strategy or through insight (i.e., sudden awareness of a solution. Study 1 investigated the relationship between trait mindfulness and compound remote associates problem solving as a function of participants’ self-reported approach to each problem. The results revealed a negative relationship between mindfulness and problem-solving overall. However, more detailed analysis revealed that mindfulness was associated with impaired problem solving when approaching problems with insight, but increased problem solving when using analysis. In Study 2, we manipulated participants’ problem-solving approach through instructions. We again found a negative relationship between mindfulness and creative performance in general, however, more mindful participants again performed better when instructed to approach problems analytically.

Dispositional mindfulness is predicted by structural development of the insula during late adolescence

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S. Friedel

2015-08-01

Full Text Available Adolescence is a critical period of development, in which the increasing social and cognitive demands of independence need to be met by enhanced self-regulatory abilities. The cultivation of mindfulness has been associated with improved self-regulation in adult populations, and it is theorized that one neurodevelopmental mechanism that supports this capacity is the development of the prefrontal cortex. The current study examined the neurodevelopmental mechanisms associated with dispositional mindfulness in adolescence. Using a longitudinal within-persons design, 82 participants underwent structural magnetic resonance imaging (MRI assessments at approximately ages 16 and 19, and also completed self-reported measurements of mindfulness at age 19. It was hypothesized that adolescents who demonstrated greater thinning of frontal cortical regions between the age of 16 and 19 would exhibit higher dispositional mindfulness levels at age 19. Results indicated that, contrary to predictions, adolescents with higher levels of mindfulness demonstrated less thinning in the left anterior insula. By contrast, higher IQ was associated with greater thinning of the right caudal middle frontal and right superior frontal regions. The involvement of insula development in mindfulness is consistent with a direct role for this structure in managing self-regulation, and in doing so concords with recent models of self-referential interoceptive awareness.

Mindfulness Is Associated with the Metabolic Syndrome among Individuals with a Depressive Symptomatology

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Erika Guyot

2018-02-01

Full Text Available The Metabolic Syndrome (MetS is a major public health burden. Dispositional mindfulness has recently been associated with eating disorders, being overweight, and could therefore be associated with the MetS. We aimed to examine in a cross-sectional design the relationship between mindfulness, the MetS, and its risk factors in a large sample of the adult general population and the influence of depressive symptomatology on this association. Adults participating in the NutriNet-Santé study who had completed the Five Facets Mindfulness Questionnaire and attended a clinical and biological examination were available for inclusion. Multivariable logistic regression models adjusted for socio-demographic and lifestyle factors were performed. A total of 17,490 individuals were included. Among individuals with a depressive symptomatology, those with higher mindfulness were less likely to have a MetS (OR: 0.73, 95% CI: 0.57–0.93, a high waist circumference, a low HDL-cholesterol level and an elevated fasting blood glucose level (all p <0.05. In those without depressive symptomatology, individuals with higher mindfulness were less likely to have a high waist circumference (p <0.01. In conclusion, higher mindfulness was associated with lower odds of developing a MetS only among individuals with a depressive symptomatology.

Biocompatible xanthan/polypyrrole scaffolds for tissue engineering

Energy Technology Data Exchange (ETDEWEB)

Blasques Bueno, Vania; Harumi Takahashi, Suelen; Catalani, Luiz Henrique; Cordoba de Torresi, Susana Ines; Siqueira Petri, Denise Freitas, E-mail: dfsp@iq.usp.br

2015-07-01

Polypyrrole (PPy) was electropolymerized in xanthan hydrogels (XCA), resulting in electroactive XCAPPy scaffolds with (15 ± 3) wt.% PPy and (40 ± 10) μm thick. The physicochemical characterization of hybrid XCAPPy scaffolds was performed by means of cyclic voltammetry, swelling tests, Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analyses (TGA), scanning electron microscopy (SEM), atomic force microscopy (AFM) and tensile tests. XCAPPy swelled ~ 80% less than XCA. FTIR spectra and thermal analyses did not evidence strong interaction between PPy and XCA matrix. XCAPPy presented a porous stratified structure resulting from the arrangement of PPy chains parallel to XCA surface. Under stress XCAPPy presented larger strain than neat XCA probably due to the sliding of planar PPy chains. The adhesion and proliferation of fibroblasts onto XCA and XCAPPy were evaluated in the absence and in the presence of external magnetic field (EMF) of 0.4 T, after one day, 7 days, 14 days and 21 days. Fibroblast proliferation was more pronounced onto XCAPPy than onto XCA, due to its higher hydrophobicity and surface roughness. EMF stimulated cell proliferation onto both scaffolds. - Highlights: • Hybrid networks of xanthan and polypyrrole were used as scaffolds for fibroblasts. • Hybrid networks were more hydrophobic and more elastic than neat xanthan. • Cell proliferation onto hybrid networks and neat xanthan increased with the time. • Cell proliferation was more pronounced onto hybrid networks than on neat xanthan. • External magnetic field stimulated cell growth onto hybrid networks and neat xanthan.

Mindful Learning: A Case Study of Langerian Mindfulness in Schools.

Science.gov (United States)

Davenport, Chase; Pagnini, Francesco

2016-01-01

The K-12 classroom applications of mindfulness as developed by Ellen Langer are discussed in a case study of a first-year charter school. Langerian Mindfulness, which is the act of drawing distinctions and noticing novelty, is deeply related to well-being and creativity, yet its impact has yet to be tested at the primary or secondary school level. The objective of the article is to display how Langerian Mindfulness strategies could increase 21st century skills and Social-Emotional Learning in primary classrooms. The New School San Francisco, an inquiry-based, socioeconomically and racially integrated charter school, serves as a model for mindful teaching and learning strategies. It is concluded that when mindful strategies are implemented, students have significant opportunities to exercise the 21st century skills of creativity, collaboration, communication and critical thinking. Langerian Mindfulness is also considered as a tool for increasing Social-Emotional Learning in integrated classrooms. It is recommended that mindful interventions be further investigated in the primary and secondary school context.

Biofunctional Ionic-Doped Calcium Phosphates: Silk Fibroin Composites for Bone Tissue Engineering Scaffolding.

Science.gov (United States)

Pina, S; Canadas, R F; Jiménez, G; Perán, M; Marchal, J A; Reis, R L; Oliveira, J M

2017-01-01

The treatment and regeneration of bone defects caused by traumatism or diseases have not been completely addressed by current therapies. Lately, advanced tools and technologies have been successfully developed for bone tissue regeneration. Functional scaffolding materials such as biopolymers and bioresorbable fillers have gained particular attention, owing to their ability to promote cell adhesion, proliferation, and extracellular matrix production, which promote new bone growth. Here, we present novel biofunctional scaffolds for bone regeneration composed of silk fibroin (SF) and β-tricalcium phosphate (β-TCP) and incorporating Sr, Zn, and Mn, which were successfully developed using salt-leaching followed by a freeze-drying technique. The scaffolds presented a suitable pore size, porosity, and high interconnectivity, adequate for promoting cell attachment and proliferation. The degradation behavior and compressive mechanical strengths showed that SF/ionic-doped TCP scaffolds exhibit improved characteristics for bone tissue engineering when compared with SF scaffolds alone. The in vitro bioactivity assays using a simulated body fluid showed the growth of an apatite layer. Furthermore, in vitro assays using human adipose-derived stem cells presented different effects on cell proliferation/differentiation when varying the doping agents in the biofunctional scaffolds. The incorporation of Zn into the scaffolds led to improved proliferation, while the Sr- and Mn-doped scaffolds presented higher osteogenic potential as demonstrated by DNA quantification and alkaline phosphatase activity. The combination of Sr with Zn led to an influence on cell proliferation and osteogenesis when compared with single ions. Our results indicate that biofunctional ionic-doped composite scaffolds are good candidates for further in vivo studies on bone tissue regeneration. © 2017 S. Karger AG, Basel.

Calming the Monkey Mind

Science.gov (United States)

Eliuk, Kendra; Chorney, David

2017-01-01

Many of today's students are experiencing higher levels of stress and anxiety in school. The need for competitive grades, the desire to be seen as perfect in a digital society, and parental pressures are only some of the reasons that students are experiencing more stress. This increased stress has lead to an overworked mind for many youth, dubbed…

The design of 3D scaffold for tissue engineering using automated scaffold design algorithm.

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Mahmoud, Shahenda; Eldeib, Ayman; Samy, Sherif

2015-06-01

Several progresses have been introduced in the field of bone regenerative medicine. A new term tissue engineering (TE) was created. In TE, a highly porous artificial extracellular matrix or scaffold is required to accommodate cells and guide their growth in three dimensions. The design of scaffolds with desirable internal and external structure represents a challenge for TE. In this paper, we introduce a new method known as automated scaffold design (ASD) for designing a 3D scaffold with a minimum mismatches for its geometrical parameters. The method makes use of k-means clustering algorithm to separate the different tissues and hence decodes the defected bone portions. The segmented portions of different slices are registered to construct the 3D volume for the data. It also uses an isosurface rendering technique for 3D visualization of the scaffold and bones. It provides the ability to visualize the transplanted as well as the normal bone portions. The proposed system proves good performance in both the segmentation results and visualizations aspects.

Trait mindfulness and protective strategies for alcohol use: Implications for college student drinking.

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Brett, Emma I; Leffingwell, Thad R; Leavens, Eleanor L

2017-10-01

The use of Protective Behavioral Strategies (PBS) has been strongly linked with decreased experience of alcohol-related consequences, making them a potential target for intervention. Additionally, mindfulness is associated with decreased experience of alcohol-related consequences. The purpose of the current study was to evaluate a model of PBS as a mediator of the effect of mindfulness on alcohol-related consequences. Additionally, mindfulness as a moderator of the relationship between PBS and alcohol use and consequences was examined. College students (N=239) at a large South Central university completed self-report measures of demographics, alcohol use and consequences, use of PBS, and trait mindfulness. Results indicated that both higher levels of mindfulness and using more PBS predicted decreased alcohol-related consequences and consumption, with PBS mediating both relationships (pmindfulness were more likely to use PBS, with individuals using more PBS experiencing fewer alcohol-related consequences and consuming fewer drinks per week. Mindfulness moderated the relationship between PBS and consequences, with a significantly stronger negative relationship for those with lower levels of mindfulness. Individuals who are higher in trait mindfulness are more likely to use PBS, which leads to a decrease in the experience of alcohol-related consequences. Furthermore, for individuals lower in mindfulness, low PBS use may lead to increased experience of alcohol consequences. Interventions that incorporate PBS may be most beneficial for students who are low in mindfulness and unlikely to engage in drinking control strategies. Copyright © 2017 Elsevier Ltd. All rights reserved.

Chitosan-based hydrogel tissue scaffolds made by 3D plotting promotes osteoblast proliferation and mineralization.

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Liu, I-Hsin; Chang, Shih-Hsin; Lin, Hsin-Yi

2015-05-13

A 3D plotting system was used to make chitosan-based tissue scaffolds with interconnected pores using pure chitosan (C) and chitosan cross-linked with pectin (CP) and genipin (CG). A freeze-dried chitosan scaffold (CF/D) was made to compare with C, to observe the effects of structural differences. The fiber size, pore size, porosity, compression strength, swelling ratio, drug release efficacy, and cumulative weight loss of the scaffolds were measured. Osteoblasts were cultured on the scaffolds and their proliferation, type I collagen production, alkaline phosphatase activity, calcium deposition, and morphology were observed. C had a lower swelling ratio, degradation, porosity and drug release efficacy and a higher compressional stiffness and cell proliferation compared to CF/D (p 3D-plotted samples, cells on CP exhibited the highest degree of mineralization after 21 d (p 3D-plotted scaffolds were stronger, less likely to degrade and better promoted osteoblast cell proliferation in vitro compared to the freeze-dried scaffolds. C, CP and CG were structurally similar, and the different crosslinking caused significant changes in their physical and biological performances.

Setd7 and its contribution to boron-induced bone regeneration in B-MBG scaffolds.

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Yin, Chengcheng; Jia, Xiaoshi; Miron, Richard J; Long, Qiaoyun; Xu, Hudi; Wei, Yan; Wu, Min; Zhang, Yufeng; Li, Zubing

2018-04-20

Boron (B), a trace element found in the human body, plays an important role for health of bone by promoting the proliferation and differentiation of osteoblasts. Our research group previously fabricated B-mesoporous bioactive glass (MBG) scaffolds, which successfully promoted osteogenic differentiation of osteoblasts when compared to pure MBG scaffolds without boron. However, the mechanisms of the positive effect of B-MBG scaffolds on osteogenesis remains unknown. Therefore, we performed in-vivo experiments in an OVX rat models with pure MBG scaffolds and compared them to B-MBG scaffold. As a result, we found that B-MBG scaffold induced more new bone regeneration compared to pure MBG scaffold and examined genes related to bone regeneration induced by B-MBG scaffold through RNA-seq to obtain target genes and epigenetic mechanisms. The results demonstrated an increased expression and affiliation of Setd7 in the B-MBG group when compared to the MBG group. Immunofluorescent staining from our in vivo samples further demonstrated a higher localization of Setd7 and H3K4me3 in Runx2-positive cells in defects treated with B-MBG scaffolds. KEGG results suggested that specifically Wnt/β-catenin signaling pathway was highly activated in new bone area associated with B-MBG scaffolds. Thereafter, in vitro studies with human bone marrow stem cells (hBMSCs) stimulated by extracted liquid of B-MBG was associated with significantly elevated levels of Setd7, as well as H3K4me3 when compared to MBG alone. To verify the role of Setd7 in new bone formation in the presence of Boron, Setd7 was knocked down in hBMSCs with stimulation of the extracted liquids of B-MBG or MBG scaffolds. The result showed that osteoblast differentiation of hBMSCs was inhibited when Setd7 was knocked down, which could not be rescued by the extract liquids of B-MBG scaffolds confirming its role in osteoblast differentiation and bone regeneration. As a histone methylase, Setd7 may be expected to be a potential

Design and characterization of microcapsules-integrated collagen matrixes as multifunctional three-dimensional scaffolds for soft tissue engineering.

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Del Mercato, Loretta L; Passione, Laura Gioia; Izzo, Daniela; Rinaldi, Rosaria; Sannino, Alessandro; Gervaso, Francesca

2016-09-01

Three-dimensional (3D) porous scaffolds based on collagen are promising candidates for soft tissue engineering applications. The addition of stimuli-responsive carriers (nano- and microparticles) in the current approaches to tissue reconstruction and repair brings about novel challenges in the design and conception of carrier-integrated polymer scaffolds. In this study, a facile method was developed to functionalize 3D collagen porous scaffolds with biodegradable multilayer microcapsules. The effects of the capsule charge as well as the influence of the functionalization methods on the binding efficiency to the scaffolds were studied. It was found that the binding of cationic microcapsules was higher than that of anionic ones, and application of vacuum during scaffolds functionalization significantly hindered the attachment of the microcapsules to the collagen matrix. The physical properties of microcapsules-integrated scaffolds were compared to pristine scaffolds. The modified scaffolds showed swelling ratios, weight losses and mechanical properties similar to those of unmodified scaffolds. Finally, in vitro diffusional tests proved that the collagen scaffolds could stably retain the microcapsules over long incubation time in Tris-HCl buffer at 37°C without undergoing morphological changes, thus confirming their suitability for tissue engineering applications. The obtained results indicate that by tuning the charge of the microcapsules and by varying the fabrication conditions, collagen scaffolds patterned with high or low number of microcapsules can be obtained, and that the microcapsules-integrated scaffolds fully retain their original physical properties. Copyright © 2016 Elsevier Ltd. All rights reserved.

Strontium eluting graphene hybrid nanoparticles augment osteogenesis in a 3D tissue scaffold

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Kumar, Sachin; Chatterjee, Kaushik

2015-01-01

The objective of this work was to prepare hybrid nanoparticles of graphene sheets decorated with strontium metallic nanoparticles and demonstrate their advantages in bone tissue engineering. Strontium-decorated reduced graphene oxide (RGO_Sr) hybrid nanoparticles were synthesized by the facile reduction of graphene oxide and strontium nitrate. X-ray diffraction, transmission electron microscopy, and atomic force microscopy revealed that the hybrid particles were composed of RGO sheets decorated with 200-300 nm metallic strontium particles. Thermal gravimetric analysis further confirmed the composition of the hybrid particles as 22 wt% of strontium. Macroporous tissue scaffolds were prepared by incorporating RGO_Sr particles in poly(ε-caprolactone) (PCL). The PCL/RGO_Sr scaffolds were found to elute strontium ions in aqueous medium. Osteoblast proliferation and differentiation was significantly higher in the PCL scaffolds containing the RGO_Sr particles in contrast to neat PCL and PCL/RGO scaffolds. The increased biological activity can be attributed to the release of strontium ions from the hybrid nanoparticles. This study demonstrates that composites prepared using hybrid nanoparticles that elute strontium ions can be used to prepare multifunctional scaffolds with good mechanical and osteoinductive properties. These findings have important implications for designing the next generation of biomaterials for use in tissue regeneration.The objective of this work was to prepare hybrid nanoparticles of graphene sheets decorated with strontium metallic nanoparticles and demonstrate their advantages in bone tissue engineering. Strontium-decorated reduced graphene oxide (RGO_Sr) hybrid nanoparticles were synthesized by the facile reduction of graphene oxide and strontium nitrate. X-ray diffraction, transmission electron microscopy, and atomic force microscopy revealed that the hybrid particles were composed of RGO sheets decorated with 200-300 nm metallic strontium

Relationship between meditative practice and self-reported mindfulness: the MINDSENS composite index.

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Joaquim Soler

Full Text Available Mindfulness has been described as an inherent human capability that can be learned and trained, and its improvement has been associated with better health outcomes in both medicine and psychology. Although the role of practice is central to most mindfulness programs, practice-related improvements in mindfulness skills is not consistently reported and little is known about how the characteristics of meditative practice affect different components of mindfulness. The present study explores the role of practice parameters on self-reported mindfulness skills. A total of 670 voluntary participants with and without previous meditation experience (n = 384 and n = 286, respectively responded to an internet-based survey on various aspects of their meditative practice (type of meditation, length of session, frequency, and lifetime practice. Participants also completed the Five Facets Mindfulness Questionnaire (FFMQ, and the Experiences Questionnaire (EQ. The group with meditation experience obtained significantly higher scores on all facets of FFMQ and EQ questionnaires compared to the group without experience. However different effect sizes were observed, with stronger effects for the Observing and Non-Reactivity facets of the FFMQ, moderate effects for Decentering in EQ, and a weak effect for Non-judging, Describing, and Acting with awareness on the FFMQ. Our results indicate that not all practice variables are equally relevant in terms of developing mindfulness skills. Frequency and lifetime practice--but not session length or meditation type--were associated with higher mindfulness skills. Given that these 6 mindfulness aspects show variable sensitivity to practice, we created a composite index (MINDSENS consisting of those items from FFMQ and EQ that showed the strongest response to practice. The MINDSENS index was able to correctly discriminate daily meditators from non-meditators in 82.3% of cases. These findings may contribute to the understanding

Relationship between meditative practice and self-reported mindfulness: the MINDSENS composite index.

Science.gov (United States)

Soler, Joaquim; Cebolla, Ausiàs; Feliu-Soler, Albert; Demarzo, Marcelo M P; Pascual, Juan C; Baños, Rosa; García-Campayo, Javier

2014-01-01

Mindfulness has been described as an inherent human capability that can be learned and trained, and its improvement has been associated with better health outcomes in both medicine and psychology. Although the role of practice is central to most mindfulness programs, practice-related improvements in mindfulness skills is not consistently reported and little is known about how the characteristics of meditative practice affect different components of mindfulness. The present study explores the role of practice parameters on self-reported mindfulness skills. A total of 670 voluntary participants with and without previous meditation experience (n = 384 and n = 286, respectively) responded to an internet-based survey on various aspects of their meditative practice (type of meditation, length of session, frequency, and lifetime practice). Participants also completed the Five Facets Mindfulness Questionnaire (FFMQ), and the Experiences Questionnaire (EQ). The group with meditation experience obtained significantly higher scores on all facets of FFMQ and EQ questionnaires compared to the group without experience. However different effect sizes were observed, with stronger effects for the Observing and Non-Reactivity facets of the FFMQ, moderate effects for Decentering in EQ, and a weak effect for Non-judging, Describing, and Acting with awareness on the FFMQ. Our results indicate that not all practice variables are equally relevant in terms of developing mindfulness skills. Frequency and lifetime practice--but not session length or meditation type--were associated with higher mindfulness skills. Given that these 6 mindfulness aspects show variable sensitivity to practice, we created a composite index (MINDSENS) consisting of those items from FFMQ and EQ that showed the strongest response to practice. The MINDSENS index was able to correctly discriminate daily meditators from non-meditators in 82.3% of cases. These findings may contribute to the understanding of the

Neuronal Networks on Nanocellulose Scaffolds.

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Jonsson, Malin; Brackmann, Christian; Puchades, Maja; Brattås, Karoline; Ewing, Andrew; Gatenholm, Paul; Enejder, Annika

2015-11-01

Proliferation, integration, and neurite extension of PC12 cells, a widely used culture model for cholinergic neurons, were studied in nanocellulose scaffolds biosynthesized by Gluconacetobacter xylinus to allow a three-dimensional (3D) extension of neurites better mimicking neuronal networks in tissue. The interaction with control scaffolds was compared with cationized nanocellulose (trimethyl ammonium betahydroxy propyl [TMAHP] cellulose) to investigate the impact of surface charges on the cell interaction mechanisms. Furthermore, coatings with extracellular matrix proteins (collagen, fibronectin, and laminin) were investigated to determine the importance of integrin-mediated cell attachment. Cell proliferation was evaluated by a cellular proliferation assay, while cell integration and neurite propagation were studied by simultaneous label-free Coherent anti-Stokes Raman Scattering and second harmonic generation microscopy, providing 3D images of PC12 cells and arrangement of nanocellulose fibrils, respectively. Cell attachment and proliferation were enhanced by TMAHP modification, but not by protein coating. Protein coating instead promoted active interaction between the cells and the scaffold, hence lateral cell migration and integration. Irrespective of surface modification, deepest cell integration measured was one to two cell layers, whereas neurites have a capacity to integrate deeper than the cell bodies in the scaffold due to their fine dimensions and amoeba-like migration pattern. Neurites with lengths of >50 μm were observed, successfully connecting individual cells and cell clusters. In conclusion, TMAHP-modified nanocellulose scaffolds promote initial cellular scaffold adhesion, which combined with additional cell-scaffold treatments enables further formation of 3D neuronal networks.

Mindful Learning: A Case Study of Langerian Mindfulness in Schools

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Chase Davenport

2016-09-01

Full Text Available The K-12 classroom applications of mindfulness as developed by Ellen Langer are discussed in a case study of a first-year charter school. Langerian Mindfulness, which is the act of drawing distinctions and noticing novelty, is deeply related to well-being and creativity, yet its impact has yet to be tested at the primary or secondary school level. The objective of the article is to display how Langerian Mindfulness strategies could increase 21st century skills and Social-Emotional Learning in primary classrooms. The New School San Francisco, an inquiry-based, socioeconomically and racially integrated charter school, serves as a model for mindful teaching and learning strategies. It is concluded that when mindful strategies are implemented, students have significant opportunities to exercise the 21st century skills of creativity, collaboration, communication and critical thinking. Langerian Mindfulness is also considered as a tool for increasing Social-Emotional Learning in integrated classrooms. It is recommended that mindful interventions be further investigated in the primary and secondary school context.

Evaluating protein incorporation and release in electrospun composite scaffolds for bone tissue engineering applications.

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Briggs, Tonye; Matos, Jeffrey; Collins, George; Arinzeh, Treena Livingston

2015-10-01

Electrospun polymer/ceramic composites have gained interest for use as scaffolds for bone tissue engineering applications. In this study, we investigated methods to incorporate Platelet Derived Growth Factor-BB (PDGF-BB) in electrospun polycaprolactone (PCL) or PCL prepared with polyethylene oxide (PEO), where both contained varying levels (up to 30 wt %) of ceramic composed of biphasic calcium phosphates, hydroxyapatite (HA)/β-tricalcium phosphate (TCP). Using a model protein, lysozyme, we compared two methods of protein incorporation, adsorption and emulsion electrospinning. Adsorption of lysozyme on scaffolds with ceramic resulted in minimal release of lysozyme over time. Using emulsion electrospinning, lysozyme released from scaffolds containing a high concentration of ceramic where the majority of the release occurred at later time points. We investigated the effect of reducing the electrostatic interaction between the protein and the ceramic on protein release with the addition of the cationic surfactant, cetyl trimethylammonium bromide (CTAB). In vitro release studies demonstrated that electrospun scaffolds prepared with CTAB released more lysozyme or PDGF-BB compared with scaffolds without the cationic surfactant. Human mesenchymal stem cells (MSCs) on composite scaffolds containing PDGF-BB incorporated through emulsion electrospinning expressed higher levels of osteogenic markers compared to scaffolds without PDGF-BB, indicating that the bioactivity of the growth factor was maintained. This study revealed methods for incorporating growth factors in polymer/ceramic scaffolds to promote osteoinduction and thereby facilitate bone regeneration. © 2015 Wiley Periodicals, Inc.

A Mind of Three Minds: Evolution of the Human Brain

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MacLean, Paul D.

1978-01-01

The author examines the evolutionary and neural roots of a triune intelligence comprised of a primal mind, an emotional mind, and a rational mind. A simple brain model and some definitions of unfamiliar behavioral terms are included. (Author/MA)

Electrospun polyurethane/hydroxyapatite bioactive scaffolds for bone tissue engineering: the role of solvent and hydroxyapatite particles.

Science.gov (United States)

Tetteh, G; Khan, A S; Delaine-Smith, R M; Reilly, G C; Rehman, I U

2014-11-01

Polyurethane (PU) is a promising polymer to support bone-matrix producing cells due to its durability and mechanical resistance. In this study two types of medical grade poly-ether urethanes Z3A1 and Z9A1 and PU-Hydroxyapatite (PU-HA) composites were investigated for their ability to act as a scaffold for tissue engineered bone. PU dissolved in varying concentrations of dimethylformamide (DMF) and tetrahydrofuran (THF) solvents were electrospun to attain scaffolds with randomly orientated non-woven fibres. Bioactive polymeric composite scaffolds were created using 15 wt% Z3A1 in a 70/30 DMF/THF PU solution and incorporating micro- or nano-sized HA particles in a ratio of 3:1 respectively, whilst a 25 wt% Z9A1 PU solution was doped in ratio of 5:1. Chemical properties of the resulting composites were evaluated by FTIR and physical properties by SEM. Tensile mechanical testing was carried out on all electrospun scaffolds. MLO-A5 osteoblastic mouse cells and human embryonic mesenchymal progenitor cells, hES-MPs were seeded on the scaffolds to test their biocompatibility and ability to support mineralised matrix production over a 28 day culture period. Cell viability was assayed by MTT and calcium and collagen deposition by Sirius red and alizarin red respectively. SEM images of both electrospun PU scaffolds and PU-HA composite scaffolds showed differences in fibre morphology with changes in solvent combinations and size of HA particles. Inclusion of THF eliminated the presence of beads in fibres that were present in scaffolds fabricated with 100% DMF solvent, and resulted in fibres with a more uniform morphology and thicker diameters. Mechanical testing demonstrated that the Young׳s Modulus and yield strength was lower at higher THF concentrations. Inclusion of both sizes of HA particles in PU-HA solutions reinforced the scaffolds leading to higher mechanical properties, whilst FTIR characterisation confirmed the presence of HA in all composite scaffolds. Although

Psycho-physiologic emergentism; four minds in a body

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David L. Rowland

2017-10-01

Full Text Available The mind-body problem represents one of the most debated topics in the neurosciences. From a psychological standpoint, abstract/non-material data are an intrinsic part of the mind, intervening to a large extent in reasoning and decision making processes. Imaging studies also show a strong correlation between higher cognitive functions (such as working memory and specific cerebral brain regions (a fronto-parietal network of interacting left and right brain areas. In contrast, the physical/material brain would be unable to interact with abstract-immaterial data, such that the psychological processing of abstract data (processes such as thinking, reasoning, and judgment is attributed to the mind, with the mind representing a distinct entity interposed between the brain and abstract-immaterial data. Recent data suggest that the mind-body problem may simply be an artifact of human experience/ understanding, as the brain actually represents actually an intrinsic part of the mind. Even if the physical brain is not able to interact with abstract mental data, the brain still could process abstract data through a dynamic association between the abstract data and cerebral stimuli/ impulses. This form of processing without interaction defines the mind as a complex neurobiological structure, with the unconscious part of the mind processing abstract-immaterial data in a conscious/ mental format. In this overview, important concepts of psycho-physiologic emergentism, including internal mental reality, internal mental existence, internal mental interaction, and structural and informational dichotomies of the brain, are iterated. Such concepts/properties represent a neuro-informational support system capable of generating four distinct minds within the single brain. Future studies should further develop the dynamic and immaterial-material nature of the mind, as a possible premise for a scientific definition and understanding of mental events like affectivity

The External Mind

DEFF Research Database (Denmark)

, Extended Mind and Distributed Cognition by Claudio Paolucci pp. 69-96 The Social Horizon of Embodied Language and Material Symbols by Riccardo Fusaroli pp. 97-123 Semiotics and Theories of Situated/Distributed Action and Cognition: a Dialogue and Many Intersections by Tommaso Granelli pp. 125-167 Building......The External Mind: an Introduction by Riccardo Fusaroli, Claudio Paolucci pp. 3-31 The sign of the Hand: Symbolic Practices and the Extended Mind by Massimiliano Cappuccio, Michael Wheeler pp. 33-55 The Overextended Mind by Shaun Gallagher pp. 57-68 The "External Mind": Semiotics, Pragmatism...

Single-minded and the evolution of the ventral midline in arthropods.

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Linne, Viktoria; Eriksson, Bo Joakim; Stollewerk, Angelika

2012-04-01

In insects and crustaceans, ventral midline cells are present that subdivide the CNS into bilateral symmetric halves. In both arthropod groups unpaired midline neurons and glial cells have been identified that contribute to the embryonic patterning mechanisms. In the fruitfly Drosophila melanogaster, for example, the midline cells are involved in neural cell fate specification along the dorso-ventral axis but also in axonal pathfinding and organisation of the axonal scaffold. Both in insects and malacostracan crustaceans, the bHLH-PAS transcription factor single-minded is the master regulator of ventral midline development and homology has been suggested for individual midline precursors in these groups. The conserved arrangement of the axonal scaffold as well as the regular pattern of neural precursors in all euarthropod groups raises the question whether the ventral midline system is conserved in this phylum. In the remaining euarthropod groups, the chelicerates and myriapods, a single-minded homologue has been identified in the spider Achaearanea tepidariorum (chelicerate), however, the gene is not expressed in the ventral midline but in the median area of the ventral neuroectoderm. Here we show that At-sim is not required for ventral midline development. Furthermore, we identify sim homologues in representatives of arthropods that have not yet been analysed: the myriapod Strigamia maritima and a representative of an outgroup to the euarthropods, the onychophoran Euperipatoides kanangrensis. We compare the expression patterns to the A. tepidariorum sim homologue expression and furthermore analyse the nature of the arthropod midline cells. Our data suggest that in arthropods unpaired midline precursors evolved from the bilateral median domain of the ventral neuroectoderm in the last common ancestor of Mandibulata (insects, crustaceans, myriapods). We hypothesize that sim was expressed in this domain and recruited to ventral midline development. Subsequently, sim

Toward physics of the mind: Concepts, emotions, consciousness, and symbols

Science.gov (United States)

Perlovsky, Leonid I.

2006-03-01

Mathematical approaches to modeling the mind since the 1950s are reviewed, including artificial intelligence, pattern recognition, and neural networks. I analyze difficulties faced by these algorithms and neural networks and relate them to the fundamental inconsistency of logic discovered by Gödel. Mathematical discussions are related to those in neurobiology, psychology, cognitive science, and philosophy. Higher cognitive functions are reviewed including concepts, emotions, instincts, understanding, imagination, intuition, consciousness. Then, I describe a mathematical formulation, unifying the mind mechanisms in a psychologically and neuro-biologically plausible system. A mechanism of the knowledge instinct drives our understanding of the world and serves as a foundation for higher cognitive functions. This mechanism relates aesthetic emotions and perception of beauty to “everyday” functioning of the mind. The article reviews mechanisms of human symbolic ability. I touch on future directions: joint evolution of the mind, language, consciousness, and cultures; mechanisms of differentiation and synthesis; a manifold of aesthetic emotions in music and differentiated instinct for knowledge. I concentrate on elucidating the first principles; review aspects of the theory that have been proven in laboratory research, relationships between the mind and brain; discuss unsolved problems, and outline a number of theoretical predictions, which will have to be tested in future mathematical simulations and neuro-biological research.

Multilayer scaffolds in orthopaedic tissue engineering.

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Atesok, Kivanc; Doral, M Nedim; Karlsson, Jon; Egol, Kenneth A; Jazrawi, Laith M; Coelho, Paulo G; Martinez, Amaury; Matsumoto, Tomoyuki; Owens, Brett D; Ochi, Mitsuo; Hurwitz, Shepard R; Atala, Anthony; Fu, Freddie H; Lu, Helen H; Rodeo, Scott A

2016-07-01

The purpose of this study was to summarize the recent developments in the field of tissue engineering as they relate to multilayer scaffold designs in musculoskeletal regeneration. Clinical and basic research studies that highlight the current knowledge and potential future applications of the multilayer scaffolds in orthopaedic tissue engineering were evaluated and the best evidence collected. Studies were divided into three main categories based on tissue types and interfaces for which multilayer scaffolds were used to regenerate: bone, osteochondral junction and tendon-to-bone interfaces. In vitro and in vivo studies indicate that the use of stratified scaffolds composed of multiple layers with distinct compositions for regeneration of distinct tissue types within the same scaffold and anatomic location is feasible. This emerging tissue engineering approach has potential applications in regeneration of bone defects, osteochondral lesions and tendon-to-bone interfaces with successful basic research findings that encourage clinical applications. Present data supporting the advantages of the use of multilayer scaffolds as an emerging strategy in musculoskeletal tissue engineering are promising, however, still limited. Positive impacts of the use of next generation scaffolds in orthopaedic tissue engineering can be expected in terms of decreasing the invasiveness of current grafting techniques used for reconstruction of bone and osteochondral defects, and tendon-to-bone interfaces in near future.

Titanate nanotube coatings on biodegradable photopolymer scaffolds

Energy Technology Data Exchange (ETDEWEB)

Beke, S., E-mail: szabolcs.beke@iit.it [Department of Nanophysics, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova (Italy); Kőrösi, L. [Department of Biotechnology, Nanophage Therapy Center, Enviroinvest Corporation, Kertváros u. 2, H-7632, Pécs (Hungary); Scarpellini, A. [Department of Nanochemistry, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova (Italy); Anjum, F.; Brandi, F. [Department of Nanophysics, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova (Italy)

2013-05-01

Rigid, biodegradable photopolymer scaffolds were coated with titanate nanotubes (TNTs) by using a spin-coating method. TNTs were synthesized by a hydrothermal process at 150 °C under 4.7 bar ambient pressure. The biodegradable photopolymer scaffolds were produced by mask-assisted excimer laser photocuring at 308 nm. For scaffold coating, a stable ethanolic TNT sol was prepared by a simple colloid chemical route without the use of any binding compounds or additives. Scanning electron microscopy along with elemental analysis revealed that the scaffolds were homogenously coated by TNTs. The developed TNT coating can further improve the surface geometry of fabricated scaffolds, and therefore it can further increase the cell adhesion. Highlights: ► Biodegradable scaffolds were produced by mask-assisted UV laser photocuring. ► Titanate nanotube deposition was carried out without binding compounds or additives. ► The titanate nanotube coating can further improve the surface geometry of scaffolds. ► These reproducible platforms will be of high importance for biological applications.

Contribution of Mindfulness and Emotional Intelligence to Burnout among Counseling Interns

Science.gov (United States)

Testa, Daniel; Sangganjanavanich, Varunee Faii

2016-01-01

The authors examined the contribution of mindfulness and emotional intelligence to burnout among counseling interns (N = 380). Results indicated that higher scores on mindfulness and emotional intelligence were related to lower burnout scores. Counselor educators and supervisors should be proactive in helping students to cultivate wellness…

Feasibility of autologous bone marrow mesenchymal stem cell-derived extracellular matrix scaffold for cartilage tissue engineering.

Science.gov (United States)

Tang, Cheng; Xu, Yan; Jin, Chengzhe; Min, Byoung-Hyun; Li, Zhiyong; Pei, Xuan; Wang, Liming

2013-12-01

Extracellular matrix (ECM) materials are widely used in cartilage tissue engineering. However, the current ECM materials are unsatisfactory for clinical practice as most of them are derived from allogenous or xenogenous tissue. This study was designed to develop a novel autologous ECM scaffold for cartilage tissue engineering. The autologous bone marrow mesenchymal stem cell-derived ECM (aBMSC-dECM) membrane was collected and fabricated into a three-dimensional porous scaffold via cross-linking and freeze-drying techniques. Articular chondrocytes were seeded into the aBMSC-dECM scaffold and atelocollagen scaffold, respectively. An in vitro culture and an in vivo implantation in nude mice model were performed to evaluate the influence on engineered cartilage. The current results showed that the aBMSC-dECM scaffold had a good microstructure and biocompatibility. After 4 weeks in vitro culture, the engineered cartilage in the aBMSC-dECM scaffold group formed thicker cartilage tissue with more homogeneous structure and higher expressions of cartilaginous gene and protein compared with the atelocollagen scaffold group. Furthermore, the engineered cartilage based on the aBMSC-dECM scaffold showed better cartilage formation in terms of volume and homogeneity, cartilage matrix content, and compressive modulus after 3 weeks in vivo implantation. These results indicated that the aBMSC-dECM scaffold could be a successful novel candidate scaffold for cartilage tissue engineering. © 2013 Wiley Periodicals, Inc. and International Center for Artificial Organs and Transplantation.

Construction and characterization of an electrospun tubular scaffold for small-diameter tissue-engineered vascular grafts: a scaffold membrane approach.

Science.gov (United States)

Hu, Jin-Jia; Chao, Wei-Chih; Lee, Pei-Yuan; Huang, Chih-Hao

2012-09-01

Based on a postulate that the microstructure of a scaffold can influence that of the resulting tissue and hence its mechanical behavior, we fabricated a small-diameter tubular scaffold (∼3 mm inner diameter) that has a microstructure similar to the arterial media using a scaffold membrane approach. Scaffold membranes that contain randomly oriented, moderately aligned, or highly aligned fibers were fabricated by collecting electrospun poly([epsilon]-caprolactone) fibers on a grounded rotating drum at three different drum rotation speeds (250, 1000, and 1500 rpm). Membranes of each type were wrapped around a small-diameter mandrel to form the tubular scaffolds. Particularly, the tubular scaffolds with three different off-axis fiber angles (30, 45, and 60 degree) were formed using membranes that contain aligned fibers. These scaffolds were subjected to biaxial mechanical testing to examine the effects of fiber directions as well as the distribution of fiber orientations on their mechanical properties. The circumferential elastic modulus of the tubular scaffold was closely related to the fiber directions; the larger the off-axis fiber angle the greater the circumferential elastic modulus. The distribution of fiber orientations, on the other hand, manifested itself in the mechanical behavior via the Poisson effect. Similar to cell sheet-based vascular tissue engineering, tubular cell-seeded constructs were prepared by wrapping cell-seeded scaffold membranes, alleviating the difficulty associated with cell seeding in electrospun scaffolds. Histology of the construct illustrated that cells were aligned to the fiber directions in the construct, demonstrating the potential to control the microstructure of tissue-engineered vascular grafts using the electrospun scaffold membrane. Copyright © 2012 Elsevier Ltd. All rights reserved.

Factorial Study of Compressive Mechanical Properties and Primary In Vitro Osteoblast Response of PHBV/PLLA Scaffolds

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Naznin Sultana

2012-01-01

Full Text Available For bone tissue regeneration, composite scaffolds containing biodegradable polymers and nanosized osteoconductive bioceramics have been regarded as promising biomimetic systems. Polymer blends of poly(hydroxybutyrate-co-hydroxyvalerate (PHBV and poly(L-lactic acid (PLLA can be used as the polymer matrix to control the degradation rate. In order to render the scaffolds osteoconductive, nano-sized hydroxyapatite (nHA particles can be incorporated into the polymer matrix. In the first part of this study, a factorial design approach to investigate the influence of materials on the initial compressive mechanical properties of the scaffolds was studied. In the second part, the protein adsorption behavior and the attachment and morphology of osteoblast-like cells (Saos-2 of the scaffolds in vitro were also studied. It was observed that nHA incorporated PHBV/PLLA composite scaffolds adsorbed more bovine serum albumin (BSA protein than PHBV or PHBV/PLLA scaffolds. In vitro studies also revealed that the attachment of human osteoblastic cells (SaOS-2 was significantly higher in nHA incorporated PHBV/PLLA composite scaffolds. From the SEM micrographs of nHA incorporated PHBV/PLLA composite scaffolds seeded with SaOS-2 cells after a 7-day cell culture period, it was observed that the cells were well expanded and spread in all directions on the scaffolds.

Post Processing and Biological Evaluation of the Titanium Scaffolds for Bone Tissue Engineering.

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Wysocki, Bartłomiej; Idaszek, Joanna; Szlązak, Karol; Strzelczyk, Karolina; Brynk, Tomasz; Kurzydłowski, Krzysztof J; Święszkowski, Wojciech

2016-03-15

Nowadays, post-surgical or post-accidental bone loss can be substituted by custom-made scaffolds fabricated by additive manufacturing (AM) methods from metallic powders. However, the partially melted powder particles must be removed in a post-process chemical treatment. The aim of this study was to investigate the effect of the chemical polishing with various acid baths on novel scaffolds' morphology, porosity and mechanical properties. In the first stage, Magics software (Materialise NV, Leuven, Belgium) was used to design a porous scaffolds with pore size equal to (A) 200 µm, (B) 500 µm and (C) 200 + 500 µm, and diamond cell structure. The scaffolds were fabricated from commercially pure titanium powder (CP Ti) using a SLM50 3D printing machine (Realizer GmbH, Borchen, Germany). The selective laser melting (SLM) process was optimized and the laser beam energy density in range of 91-151 J/mm³ was applied to receive 3D structures with fully dense struts. To remove not fully melted titanium particles the scaffolds were chemically polished using various HF and HF-HNO₃ acid solutions. Based on scaffolds mass loss and scanning electron (SEM) observations, baths which provided most uniform surface cleaning were proposed for each porosity. The pore and strut size after chemical treatments was calculated based on the micro-computed tomography (µ-CT) and SEM images. The mechanical tests showed that the treated scaffolds had Young's modulus close to that of compact bone. Additionally, the effect of pore size of chemically polished scaffolds on cell retention, proliferation and differentiation was studied using human mesenchymal stem cells. Small pores yielded higher cell retention within the scaffolds, which then affected their growth. This shows that in vitro cell performance can be controlled to certain extent by varying pore sizes.

Image-based characterization of foamed polymeric tissue scaffolds

International Nuclear Information System (INIS)

Mather, Melissa L; Morgan, Stephen P; Crowe, John A; White, Lisa J; Shakesheff, Kevin M; Tai, Hongyun; Howdle, Steven M; Kockenberger, Walter

2008-01-01

Tissue scaffolds are integral to many regenerative medicine therapies, providing suitable environments for tissue regeneration. In order to assess their suitability, methods to routinely and reproducibly characterize scaffolds are needed. Scaffold structures are typically complex, and thus their characterization is far from trivial. The work presented in this paper is centred on the application of the principles of scaffold characterization outlined in guidelines developed by ASTM International. Specifically, this work demonstrates the capabilities of different imaging modalities and analysis techniques used to characterize scaffolds fabricated from poly(lactic-co-glycolic acid) using supercritical carbon dioxide. Three structurally different scaffolds were used. The scaffolds were imaged using: scanning electron microscopy, micro x-ray computed tomography, magnetic resonance imaging and terahertz pulsed imaging. In each case two-dimensional images were obtained from which scaffold properties were determined using image processing. The findings of this work highlight how the chosen imaging modality and image-processing technique can influence the results of scaffold characterization. It is concluded that in order to obtain useful results from image-based scaffold characterization, an imaging methodology providing sufficient contrast and resolution must be used along with robust image segmentation methods to allow intercomparison of results

Osteoconductivity and Biodegradability of Collagen Scaffold Coated with Nano-β-TCP and Fibroblast Growth Factor 2

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Asako Ibara

2013-01-01

Full Text Available Nanoparticle bioceramics have become anticipated for biomedical applications. Highly bioactive and biodegradable scaffolds would be developed using nanoparticles of β-tricalcium phosphate (β-TCP. We prepared collagen scaffolds coated by nano-β-TCP and fibroblast growth factor 2 (FGF2 and evaluated the effects on new bone augmentation and biodegradation. The collagen sponge was coated with the nano-TCP dispersion and freeze-dried. Scaffold was characterized by SEM, TEM, XRD, compressive testing and cell seeding. Subsequently, the nano-β-TCP/collagen scaffold, collagen sponge, and each material loaded with FGF2 were implanted on rat cranial bone. As a control, no implantation was performed. Nano-TCP particles were found to be attached to the fibers of the collagen sponge by SEM and TEM observations. Scaffold coated with nano-TCP showed higher compressive strength and cytocompatibility. In histological evaluations at 10 days, inflammatory cells were rarely seen around the residual scaffold, suggesting that the nano-TCP material possesses good tissue compatibility. At 35 days, bone augmentation and scaffold degradation in histological samples receiving nano-β-TCP scaffold were significantly greater than those in the control. By loading of FGF2, advanced bone formation is facilitated, indicating that a combination with FGF2 would be effective for bone tissue engineering.

A study on improving mechanical properties of porous HA tissue engineering scaffolds by hot isostatic pressing

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Zhao Jing; Xiao Suguang; Lu Xiong; Wang Jianxin; Weng Jie

2006-01-01

Various interconnected porous hydroxyapatite (HA) ceramic scaffolds are universally used to induct the tissue growth for bone repair and replacement, and serve to support the adhesion, transfer, proliferation and differentiation of cells. Impregnation of polyurethane sponges with a ceramic slurry is adopted to produce highly porous HA ceramic scaffolds with a 3D interconnected structure. However, high porosity always accompanies a decrease in the strength of the HA ceramic scaffolds. Therefore, it is significant to improve the strength of the HA ceramic scaffolds with highly interconnected porosity so that they are more suitable in clinical applications. In this work, highly porous HA ceramic scaffolds are first produced by the polymer impregnation approach, and subsequently further sintered by hot isostatic pressing (HIP). The phase composition, macro- and micro-porous structure, sintering and mechanical properties of the porous HA scaffolds are investigated by x-ray diffraction (XRD), scanning electron microscopy (SEM), nanoindentation analysis and compressive test. The experimental results show that the nanohardness and compressive strength of HIP-sintered porous HA ceramics are higher than those of commonly sintered HA scaffolds. The HIP technique can effectively improve the sintering property and densification of porous HA ceramic scaffolds, so inducing an increase in the compression strength

Analysis Critical Thinking Stage of Eighth Grade in PBL-Scaffolding Setting To Solve Mathematical Problems

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Nur Aisyah Isti

2017-03-01

Full Text Available The purpose of this research was described critical thinking stage of students grade VIII in setting PBL and scaffolding to solve mathematics problems. Critical thinking stage consists of clarification, assesment, inference, and strategy/tactics. The subject were teo students in the level of capacity to think critical (uncritical, less critical, quite critical, and critical. So that this research subject was 8 students in VIII A One State Junior High School of Temanggung. The result showed a description (1 critical thinking stage of students in setting PBL, in clarification the higher level of capacity to think critical students, students can identification information from question fully, can identificatio problem became detailed, and can explored the relationship among the information; (2 a strategy of scaffolding were given by critical thinking stage and TKBK, in assesment, scaffolding had given was given hint/key classically; and (3 transformation characteristic of the critical thinking stage of students after given scaffolding, it because of habituation in setting PBL and scaffolding.

Microstructure, Mechanical Properties and Corrosion Behavior of Porous Mg-6 wt.% Zn Scaffolds for Bone Tissue Engineering

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Yan, Yang; Kang, Yijun; Li, Ding; Yu, Kun; Xiao, Tao; Wang, Qiyuan; Deng, Youwen; Fang, Hongjie; Jiang, Dayue; Zhang, Yu

2018-03-01

Porous Mg-based scaffolds have been extensively researched as biodegradable implants due to their attractive biological and excellent mechanical properties. In this study, porous Mg-6 wt.% Zn scaffolds were prepared by powder metallurgy using ammonium bicarbonate particles as space-holder particles. The effects of space-holder particle content on the microstructure, mechanical properties and corrosion resistance of the Mg-6 wt.% Zn scaffolds were studied. The mean porosity and pore size of the open-cellular scaffolds were within the range 6.7-52.2% and 32.3-384.2 µm, respectively. Slight oxidation was observed at the grain boundaries and on the pore walls. The Mg-6 wt.% Zn scaffolds were shown to possess mechanical properties comparable with those of natural bone and had variable in vitro degradation rates. Increased content of space-holder particles negatively affected the mechanical behavior and corrosion resistance of the Mg-6 wt.% Zn scaffolds, especially when higher than 20%. These results suggest that porous Mg-6 wt.% Zn scaffolds are promising materials for application in bone tissue engineering.

Biodegradable poly (lactic acid-co-glycolic acid scaffolds as carriers for genetically-modified fibroblasts.

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Tatjana Perisic

Full Text Available Recent advances in gene delivery into cells allow improved therapeutic effects in gene therapy trials. To increase the bioavailability of applied cells, it is of great interest that transfected cells remain at the application site and systemic spread is minimized. In this study, we tested clinically used biodegradable poly(lactic acid-co-glycolic acid (PLGA scaffolds (Vicryl & Ethisorb as transient carriers for genetically modified cells. To this aim, we used human fibroblasts and examined attachment and proliferation of untransfected cells on the scaffolds in vitro, as well as the mechanical properties of the scaffolds at four time points (1, 3, 6 and 9 days of cultivation. Furthermore, the adherence of cells transfected with green fluorescent protein (GFP and vascular endothelial growth factor (VEGF165 and also VEGF165 protein secretion were investigated. Our results show that human fibroblasts adhere on both types of PLGA scaffolds. However, proliferation and transgene expression capacity were higher on Ethisorb scaffolds most probably due to a different architecture of the scaffold. Additionally, cultivation of the cells on the scaffolds did not alter their biomechanical properties. The results of this investigation could be potentially exploited in therapeutic regiments with areal delivery of transiently transfected cells and may open the way for a variety of applications of cell-based gene therapy, tissue engineering and regenerative medicine.

A collagen-based scaffold delivering exogenous microrna-29B to modulate extracellular matrix remodeling.

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Monaghan, Michael; Browne, Shane; Schenke-Layland, Katja; Pandit, Abhay

2014-04-01

Directing appropriate extracellular matrix remodeling is a key aim of regenerative medicine strategies. Thus, antifibrotic interfering RNA (RNAi) therapy with exogenous microRNA (miR)-29B was proposed as a method to modulate extracellular matrix remodeling following cutaneous injury. It was hypothesized that delivery of miR-29B from a collagen scaffold will efficiently modulate the extracellular matrix remodeling response and reduce maladaptive remodeling such as aggressive deposition of collagen type I after injury. The release of RNA from the scaffold was assessed and its ability to silence collagen type I and collagen type III expression was evaluated in vitro. When primary fibroblasts were cultured with scaffolds doped with miR-29B, reduced levels of collagen type I and collagen type III mRNA expression were observed for up to 2 weeks of culture. When the scaffolds were applied to full thickness wounds in vivo, reduced wound contraction, improved collagen type III/I ratios and a significantly higher matrix metalloproteinase (MMP)-8: tissue inhibitor of metalloproteinase (TIMP)-1 ratio were detected when the scaffolds were functionalized with miR-29B. Furthermore, these effects were significantly influenced by the dose of miR-29B in the collagen scaffold (0.5 versus 5 μg). This study shows a potential of combining exogenous miRs with collagen scaffolds to improve extracellular matrix remodeling following injury.

Surface modification of nanofibrous polycaprolactone/gelatin composite scaffold by collagen type I grafting for skin tissue engineering

International Nuclear Information System (INIS)

Gautam, Sneh; Chou, Chia-Fu; Dinda, Amit K.; Potdar, Pravin D.; Mishra, Narayan C.

2014-01-01

In the present study, a tri-polymer polycaprolactone (PCL)/gelatin/collagen type I composite nanofibrous scaffold has been fabricated by electrospinning for skin tissue engineering and wound healing applications. Firstly, PCL/gelatin nanofibrous scaffold was fabricated by electrospinning using a low cost solvent mixture [chloroform/methanol for PCL and acetic acid (80% v/v) for gelatin], and then the nanofibrous PCL/gelatin scaffold was modified by collagen type I (0.2–1.5 wt.%) grafting. Morphology of the collagen type I-modified PCL/gelatin composite scaffold that was analyzed by field emission scanning electron microscopy (FE-SEM), showed that the fiber diameter was increased and pore size was decreased by increasing the concentration of collagen type I. Fourier transform infrared (FT-IR) spectroscopy and thermogravimetric (TG) analysis indicated the surface modification of PCL/gelatin scaffold by collagen type I immobilization on the surface of the scaffold. MTT assay demonstrated the viability and high proliferation rate of L929 mouse fibroblast cells on the collagen type I-modified composite scaffold. FE-SEM analysis of cell-scaffold construct illustrated the cell adhesion of L929 mouse fibroblasts on the surface of scaffold. Characteristic cell morphology of L929 was also observed on the nanofiber mesh of the collagen type I-modified scaffold. Above results suggest that the collagen type I-modified PCL/gelatin scaffold was successful in maintaining characteristic shape of fibroblasts, besides good cell proliferation. Therefore, the fibroblast seeded PCL/gelatin/collagen type I composite nanofibrous scaffold might be a potential candidate for wound healing and skin tissue engineering applications. - Highlights: • PCL/gelatin/collagen type I scaffold was fabricated for skin tissue engineering. • PCL/gelatin/collagen type I scaffold showed higher fibroblast growth than PCL/gelatin one. • PCL/gelatin/collagen type I might be one of the ideal scaffold for

Porous magnesium-based scaffolds for tissue engineering

International Nuclear Information System (INIS)

Yazdimamaghani, Mostafa; Razavi, Mehdi; Vashaee, Daryoosh; Moharamzadeh, Keyvan; Boccaccini, Aldo R.; Tayebi, Lobat

2017-01-01

Significant amount of research efforts have been dedicated to the development of scaffolds for tissue engineering. Although at present most of the studies are focused on non-load bearing scaffolds, many scaffolds have also been investigated for hard tissue repair. In particular, metallic scaffolds are being studied for hard tissue engineering due to their suitable mechanical properties. Several biocompatible metallic materials such as stainless steels, cobalt alloys, titanium alloys, tantalum, nitinol and magnesium alloys have been commonly employed as implants in orthopedic and dental treatments. They are often used to replace and regenerate the damaged bones or to provide structural support for healing bone defects. Among the common metallic biomaterials, magnesium (Mg) and a number of its alloys are effective because of their mechanical properties close to those of human bone, their natural ionic content that may have important functional roles in physiological systems, and their in vivo biodegradation characteristics in body fluids. Due to such collective properties, Mg based alloys can be employed as biocompatible, bioactive, and biodegradable scaffolds for load-bearing applications. Recently, porous Mg and Mg alloys have been specially suggested as metallic scaffolds for bone tissue engineering. With further optimization of the fabrication techniques, porous Mg is expected to make a promising hard substitute scaffold. The present review covers research conducted on the fabrication techniques, surface modifications, properties and biological characteristics of Mg alloys based scaffolds. Furthermore, the potential applications, challenges and future trends of such degradable metallic scaffolds are discussed in detail. - Highlights: • A porous 3D material provides the required pathways for cells to grow, proliferate, and differentiate • Porous magnesium and Mg alloys could be used as load-bearing scaffolds • Porous magnesium and Mg alloys are good

Porous magnesium-based scaffolds for tissue engineering

Energy Technology Data Exchange (ETDEWEB)

Yazdimamaghani, Mostafa [School of Chemical Engineering, Oklahoma State University, Stillwater, OK 74078 (United States); Razavi, Mehdi [Department of Radiology, School of Medicine, Stanford University, Palo Alto, CA 94304 (United States); Vashaee, Daryoosh [Electrical and Computer Engineering Department, North Carolina State University, Raleigh, NC 27606 (United States); Moharamzadeh, Keyvan [School of Clinical Dentistry, University of Sheffield, Claremont Crescent, Sheffield (United Kingdom); Marquette University School of Dentistry, Milwaukee, WI 53233 (United States); Boccaccini, Aldo R. [Institute of Biomaterials, University of Erlangen-Nuremberg, Cauerstrasse 6, 91058 Erlangen (Germany); Tayebi, Lobat, E-mail: lobat.tayebi@marquette.edu [Marquette University School of Dentistry, Milwaukee, WI 53233 (United States)

2017-02-01

Significant amount of research efforts have been dedicated to the development of scaffolds for tissue engineering. Although at present most of the studies are focused on non-load bearing scaffolds, many scaffolds have also been investigated for hard tissue repair. In particular, metallic scaffolds are being studied for hard tissue engineering due to their suitable mechanical properties. Several biocompatible metallic materials such as stainless steels, cobalt alloys, titanium alloys, tantalum, nitinol and magnesium alloys have been commonly employed as implants in orthopedic and dental treatments. They are often used to replace and regenerate the damaged bones or to provide structural support for healing bone defects. Among the common metallic biomaterials, magnesium (Mg) and a number of its alloys are effective because of their mechanical properties close to those of human bone, their natural ionic content that may have important functional roles in physiological systems, and their in vivo biodegradation characteristics in body fluids. Due to such collective properties, Mg based alloys can be employed as biocompatible, bioactive, and biodegradable scaffolds for load-bearing applications. Recently, porous Mg and Mg alloys have been specially suggested as metallic scaffolds for bone tissue engineering. With further optimization of the fabrication techniques, porous Mg is expected to make a promising hard substitute scaffold. The present review covers research conducted on the fabrication techniques, surface modifications, properties and biological characteristics of Mg alloys based scaffolds. Furthermore, the potential applications, challenges and future trends of such degradable metallic scaffolds are discussed in detail. - Highlights: • A porous 3D material provides the required pathways for cells to grow, proliferate, and differentiate • Porous magnesium and Mg alloys could be used as load-bearing scaffolds • Porous magnesium and Mg alloys are good

Fabrication, characterization and in vitro drug release behavior of electrospun PLGA/chitosan nanofibrous scaffold

Energy Technology Data Exchange (ETDEWEB)

Meng, Z.X.; Zheng, W.; Li, L. [Center for Biomedical Materials and Engineering, Harbin Engineering University, Harbin 150001 (China); Zheng, Y.F., E-mail: yfzheng@pku.edu.cn [Center for Biomedical Materials and Engineering, Harbin Engineering University, Harbin 150001 (China); Department of Advanced Materials and Nanotechnology, College of Engineering, Peking University, Beijing 100871 (China)

2011-02-15

Graphical abstract: The fenbufen loaded PLGA/chitosan nanofibrous scaffolds were fabricated by electrospinning. The hydrophilicity of nanofibrous scaffold was enhanced with the increase of chitosan content. The drug release also is accelerated with chitosan increasing because the higher hydrophilicity makes drug diffusing from scaffold more easily. Research highlights: {yields} The average diameter increased with the increase of chitosan content and then decreased. {yields} The release rate of fenbufen increased with the increase of chitosan. {yields} The aligned nanofibrous scaffold exhibits lower drug release rate. {yields} The drug release could be controlled by crosslinking in glutaraldehyde vapor. - Abstract: In this study both aligned and randomly oriented poly(D,L-lactide-co-glycolide) (PLGA)/chitosan nanofibrous scaffold have been prepared by electrospinning. The ratio of PLGA to chitosan was adjusted to get smooth nanofiber surface. Morphological characterization using scanning electron microscopy showed that the aligned nanofiber diameter distribution obtained by electrospinning of polymer blend increased with the increase of chitosan content which was similar to that of randomly oriented nanofibers. The release characteristic of model drug fenbufen (FBF) from the FBF-loaded aligned and randomly oriented PLGA and PLGA/chitosan nanofibrous scaffolds was investigated. The drug release rate increased with the increase of chitosan content because the addition of chitosan enhanced the hydrophilicity of the PLGA/chitosan composite scaffold. Moreover, for the aligned PLGA/chitosan nanofibrous scaffold the release rate was lower than that of randomly oriented PLGA/chitosan nanofibrous scaffold, which indicated that the nanofiber arrangement would influence the release behavior. In addition, crosslinking in glutaraldehyde vapor would decrease the burst release of FBF from FBF-loaded PLGA/chitosan nanofibrous scaffold with a PLGA/chitosan ratio less than 9/1, which

Surface-modified functionalized polycaprolactone scaffolds for bone repair: in vitro and in vivo experiments.

Science.gov (United States)

Jensen, Jonas; Rölfing, Jan Hendrik Duedal; Le, Dang Quang Svend; Kristiansen, Asger Albaek; Nygaard, Jens Vinge; Hokland, Lea Bjerre; Bendtsen, Michael; Kassem, Moustapha; Lysdahl, Helle; Bünger, Cody Eric

2014-09-01

A porcine calvaria defect study was carried out to investigate the bone repair potential of three-dimensional (3D)-printed poly-ε-caprolactone (PCL) scaffolds embedded with nanoporous PCL. A microscopic grid network was created by rapid prototyping making a 3D-fused deposition model (FDM-PCL). Afterward, the FDM-PCL scaffolds were infused with a mixture of PCL, water, and 1,4-dioxane and underwent a thermal-induced phase separation (TIPS) followed by lyophilization. The TIPS process lead to a nanoporous structure shielded by the printed microstructure (NSP-PCL). Sixteen Landrace pigs were divided into two groups with 8 and 12 weeks follow-up, respectively. A total of six nonpenetrating holes were drilled in the calvaria of each animal. The size of the cylindrical defects was h 10 mm and Ø 10 mm. The defects were distributed randomly using following groups: (a) NSP-PCL scaffold, (b) FDM-PCL scaffold, (c) autograft, (d) empty defect, (a1) NSP-PCL scaffold + autologous mononuclear cells, and (a2) NSP-PCL scaffold + bone morphogenetic protein 2. Bone volume to total volume was analyzed using microcomputed tomography (µCT) and histomorphometry. The µCT and histological data showed significantly less bone formation in the NSP-PCL scaffolds in all three variations after both 8 and 12 weeks compared to all other groups. The positive autograft control had significantly higher new bone formation compared to all other groups except the FDM-PCL when analyzed using histomorphometry. The NSP-PCL scaffolds were heavily infiltrated with foreign body giant cells suggesting an inflammatory response and perhaps active resorption of the scaffold material. The unmodified FDM-PCL scaffold showed good osteoconductivity and osseointegration after both 8 and 12 weeks. © 2013 Wiley Periodicals, Inc.

Fabrication, characterization and in vitro drug release behavior of electrospun PLGA/chitosan nanofibrous scaffold

International Nuclear Information System (INIS)

Meng, Z.X.; Zheng, W.; Li, L.; Zheng, Y.F.

2011-01-01

Graphical abstract: The fenbufen loaded PLGA/chitosan nanofibrous scaffolds were fabricated by electrospinning. The hydrophilicity of nanofibrous scaffold was enhanced with the increase of chitosan content. The drug release also is accelerated with chitosan increasing because the higher hydrophilicity makes drug diffusing from scaffold more easily. Research highlights: → The average diameter increased with the increase of chitosan content and then decreased. → The release rate of fenbufen increased with the increase of chitosan. → The aligned nanofibrous scaffold exhibits lower drug release rate. → The drug release could be controlled by crosslinking in glutaraldehyde vapor. - Abstract: In this study both aligned and randomly oriented poly(D,L-lactide-co-glycolide) (PLGA)/chitosan nanofibrous scaffold have been prepared by electrospinning. The ratio of PLGA to chitosan was adjusted to get smooth nanofiber surface. Morphological characterization using scanning electron microscopy showed that the aligned nanofiber diameter distribution obtained by electrospinning of polymer blend increased with the increase of chitosan content which was similar to that of randomly oriented nanofibers. The release characteristic of model drug fenbufen (FBF) from the FBF-loaded aligned and randomly oriented PLGA and PLGA/chitosan nanofibrous scaffolds was investigated. The drug release rate increased with the increase of chitosan content because the addition of chitosan enhanced the hydrophilicity of the PLGA/chitosan composite scaffold. Moreover, for the aligned PLGA/chitosan nanofibrous scaffold the release rate was lower than that of randomly oriented PLGA/chitosan nanofibrous scaffold, which indicated that the nanofiber arrangement would influence the release behavior. In addition, crosslinking in glutaraldehyde vapor would decrease the burst release of FBF from FBF-loaded PLGA/chitosan nanofibrous scaffold with a PLGA/chitosan ratio less than 9/1, which would be beneficial

Effect of Chemistry on Osteogenesis and Angiogenesis Towards Bone Tissue Engineering Using 3D Printed Scaffolds.

Science.gov (United States)

Bose, Susmita; Tarafder, Solaiman; Bandyopadhyay, Amit

2017-01-01

The functionality or survival of tissue engineering constructs depends on the adequate vascularization through oxygen transport and metabolic waste removal at the core. This study reports the presence of magnesium and silicon in direct three dimensional printed (3DP) tricalcium phosphate (TCP) scaffolds promotes in vivo osteogenesis and angiogenesis when tested in rat distal femoral defect model. Scaffolds with three different interconnected macro pore sizes were fabricated using direct three dimensional printing. In vitro ion release in phosphate buffer for 30 days showed sustained Mg 2+  and Si 4+  release from these scaffolds. Histolomorphology and histomorphometric analysis from the histology tissue sections revealed a significantly higher bone formation, between 14 and 20% for 4-16 weeks, and blood vessel formation, between 3 and 6% for 4-12 weeks, due to the presence of magnesium and silicon in TCP scaffolds compared to bare TCP scaffolds. The presence of magnesium in these 3DP TCP scaffolds also caused delayed TRAP activity. These results show that magnesium and silicon incorporated 3DP TCP scaffolds with multiscale porosity have huge potential for bone tissue repair and regeneration.

"Mind the trap": mindfulness practice reduces cognitive rigidity.

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Jonathan Greenberg

Full Text Available Two experiments examined the relation between mindfulness practice and cognitive rigidity by using a variation of the Einstellung water jar task. Participants were required to use three hypothetical jars to obtain a specific amount of water. Initial problems were solvable by the same complex formula, but in later problems ("critical" or "trap" problems solving was possible by an additional much simpler formula. A rigidity score was compiled through perseverance of the complex formula. In Experiment 1, experienced mindfulness meditators received significantly lower rigidity scores than non-meditators who had registered for their first meditation retreat. Similar results were obtained in randomized controlled Experiment 2 comparing non-meditators who underwent an eight meeting mindfulness program with a waiting list group. The authors conclude that mindfulness meditation reduces cognitive rigidity via the tendency to be "blinded" by experience. Results are discussed in light of the benefits of mindfulness practice regarding a reduced tendency to overlook novel and adaptive ways of responding due to past experience, both in and out of the clinical setting.

Teachers' dispositional mindfulness and the quality of their relationships with children in Head Start classrooms.

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Becker, Brandon D; Gallagher, Kathleen C; Whitaker, Robert C

2017-12-01

The quality of teachers' relationships with children is a key predictor of children's later social emotional competence and academic achievement. Interventions to increase mindfulness among teachers have focused primarily on the impacts on teachers' subjective well-being, but not on the quality of their relationships with children. Furthermore, none of these interventions have involved preschool teachers. To consider the potential of mindfulness-based interventions to improve the quality of teachers' relationships with preschool-aged children, we examined data from an online survey of 1001 classroom teachers in 37 Pennsylvania Head Start Programs. Using path analysis we investigated the association between teachers' dispositional mindfulness and the quality of their relationships with children (conflict and closeness). We further examined whether this association was mediated by teacher depressive symptoms and moderated by perceived workplace stress. Higher levels of dispositional mindfulness among teachers were associated with higher quality relationships with children (less conflict and greater closeness). The association between greater dispositional mindfulness and less conflict was partially mediated by lower depressive symptoms, and the conditional direct effect of mindfulness on conflict was stronger when perceived workplace stress was lower. These findings suggest that preschool teachers who have higher levels of dispositional mindfulness may experience higher quality relationships with children in their classrooms. Interventions to increase levels of dispositional mindfulness among early childhood educators may improve their well-being along with the quality of their relationships with children, potentially impacting children's educational outcomes. The potential impacts of such interventions may be even stronger if structural and systemic changes are also made to reduce workplace stress. Copyright © 2017 Society for the Study of School Psychology

Preparation, characterization and biological test of 3D-scaffolds based on chitosan, fibroin and hydroxyapatite for bone tissue engineering.

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Lima, Paulo Autran Leite; Resende, Cristiane Xavier; Soares, Glória Dulce de Almeida; Anselme, Karine; Almeida, Luís Eduardo

2013-08-01

This work describes the preparation and characterization of porous 3D-scaffolds based on chitosan (CHI), chitosan/silk fibroin (CHI/SF) and chitosan/silk fibroin/hydroxyapatite (CHI/SF/HA) by freeze drying. The biomaterials were characterized by X-ray diffraction, attenuated total reflection Fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, scanning electron microscopy and energy dispersive spectroscopy. In addition, studies of porosity, pore size, contact angle and biological response of SaOs-2osteoblastic cells were performed. The CHI scaffolds have a porosity of 94.2±0.9%, which is statistically higher than the one presented by CHI/SF/HA scaffolds, 89.7±2.6%. Although all scaffolds were able to promote adhesion, growth and maintenance of osteogenic differentiation of SaOs-2 cells, the new 3D-scaffold based on CHI/SF/HA showed a significantly higher cell growth at 7 days and 21 days and the level of alkaline phosphatase at 14 and 21 days was statistically superior compared to other tested materials. Copyright © 2013 Elsevier B.V. All rights reserved.

Preparation of Porous Scaffolds from Silk Fibroin Extracted from the Silk Gland of Bombyx mori (B. mori

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Liangjun Zhu

2012-06-01

Full Text Available In order to use a simple and ecofriendly method to prepare porous silk scaffolds, aqueous silk fibroin solution (ASF was extracted from silk gland of 7-day-old fifth instar larvae of Bombyx mori (B. mori. SDS-page analysis indicated that the obtained fibroin had a molecular weight higher than 200 kDa. The fabrication of porous scaffolds from ASF was achieved by using the freeze-drying method. The pore of porous scaffolds is homogenous and tends to become smaller with an increase in the concentration of ASF. Conversely, the porosity is decreased. The porous scaffolds show impressive compressive strength which can be as high as 6.9 ± 0.4 MPa. Furthermore, ASF has high cell adhesion and growth activity. It also exhibits high ALP activity. This implies that porous scaffolds prepared from ASF have biocompatibility. Therefore, the porous scaffolds prepared in this study have potential application in tissue engineering due to the impressive compressive strength and biocompatibility.

A graded graphene oxide-hydroxyapatite/silk fibroin biomimetic scaffold for bone tissue engineering.

Science.gov (United States)

Wang, Qian; Chu, Yanyan; He, Jianxin; Shao, Weili; Zhou, Yuman; Qi, Kun; Wang, Lidan; Cui, Shizhong

2017-11-01

To better mimic natural bone, a graphene oxide-hydroxyapatite/silk fibroin (cGO-HA/SF) scaffold was fabricated by biomineralizing carboxylated GO sheets, blending with SF, and freeze-drying. The material has increasing porosity and decreasing density from outside to inside. Analysis of GO mineralization in simulated body fluid indicated that carboxylation and Chitosan may synergistically regulate HA growth along the c-axis of weakly crystalline, rod-like GO-HA particles. Compared with HA/SF gradient composites, a cGO-HA gradient scaffold with cGO:HA mass ratio 1:4 has 5-fold and 2.5-fold higher compressive strength and compressive modulus, respectively. Additionally, the cGO-HA/SF composite stimulated mouse mesenchymal stem cell adhesion and proliferation, alkaline phosphatase secretion, and mineral deposition more strongly than HA/SF and pure HA scaffolds. Hence, the material may prove to be an excellent and versatile scaffold for bone tissue engineering. Copyright © 2017 Elsevier B.V. All rights reserved.

Recombinant protein scaffolds for tissue engineering

International Nuclear Information System (INIS)

Werkmeister, Jerome A; Ramshaw, John A M

2012-01-01

New biological materials for tissue engineering are now being developed using common genetic engineering capabilities to clone and express a variety of genetic elements that allow cost-effective purification and scaffold fabrication from these recombinant proteins, peptides or from chimeric combinations of these. The field is limitless as long as the gene sequences are known. The utility is dependent on the ease, product yield and adaptability of these protein products to the biomedical field. The development of recombinant proteins as scaffolds, while still an emerging technology with respect to commercial products, is scientifically superior to current use of natural materials or synthetic polymer scaffolds, in terms of designing specific structures with desired degrees of biological complexities and motifs. In the field of tissue engineering, next generation scaffolds will be the key to directing appropriate tissue regeneration. The initial period of biodegradable synthetic scaffolds that provided shape and mechanical integrity, but no biological information, is phasing out. The era of protein scaffolds offers distinct advantages, particularly with the combination of powerful tools of molecular biology. These include, for example, the production of human proteins of uniform quality that are free of infectious agents and the ability to make suitable quantities of proteins that are found in low quantity or are hard to isolate from tissue. For the particular needs of tissue engineering scaffolds, fibrous proteins like collagens, elastin, silks and combinations of these offer further advantages of natural well-defined structural scaffolds as well as endless possibilities of controlling functionality by genetic manipulation. (topical review)

3D polylactide-based scaffolds for studying human hepatocarcinoma processes in vitro

International Nuclear Information System (INIS)

Scaffaro, Roberto; Lo Re, Giada; Rigogliuso, Salvatrice; Ghersi, Giulio

2012-01-01

We evaluated the combination of leaching techniques and melt blending of polymers and particles for the preparation of highly interconnected three-dimensional polymeric porous scaffolds for in vitro studies of human hepatocarcinoma processes. More specifically, sodium chloride and poly(ethylene glycol) (PEG) were used as water-soluble porogens to form porous and solvent-free poly(L,D-lactide) (PLA)-based scaffolds. Several characterization techniques, including porosimetry, image analysis and thermogravimetry, were combined to improve the reliability of measurements and mapping of the size, distribution and microarchitecture of pores. We also investigated the effect of processing, in PLA-based blends, on the simultaneous bulk/surface modifications and pore architectures in the scaffolds, and assessed the effects on human hepatocarcinoma viability and cell adhesion. The influence of PEG molecular weight on the scaffold morphology and cell viability and adhesion were also investigated. Morphological studies indicated that it was possible to obtain scaffolds with well-interconnected pores of assorted sizes. The analysis confirmed that SK-Hep1 cells adhered well to the polymeric support and emitted surface protrusions necessary to grow and differentiate three-dimensional systems. PEGs with higher molecular weight showed the best results in terms of cell adhesion and viability. (paper)

PENERAPAN METODE MIND MAPPING PADA PEMBELAJARAN MATEMATIKA

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Rahma Faelasofi

2016-09-01

Full Text Available The objectives of this research was to solve how to increase students learning mathematic achievments on the subject of statistic. This study aims to determine whether the students learning mathematic achievments of the student SMP Muhammadiyah 1 Gadingrejo in the academic year of 2014-2015 using learning method mind mapping on the subject of statistics can be higher than the students’ learning mathematic achievments without using learning method mind mapping. This research is a quantitative approach. The population was all of the students in first grade of the SMP Muhammadiyah 1 Gadingrejo in the academic year of 2014- 2015. The samples of the research were taken by using the cluster random sampling technique. Based on hypothesis test, it can be included that there are differences in the average student learning achievments between using learning method mind mapping and learning method lecture on the subject of Statistics of the student in first grade of the SMP Muhammadiyah 1 Gadingrejo in the academic year of 2014-2015. Keywords: learning method mind mapping, students’ learning mathematic achievments

Relevance of fiber integrated gelatin-nanohydroxyapatite composite scaffold for bone tissue regeneration

Science.gov (United States)

Halima Shamaz, Bibi; Anitha, A.; Vijayamohan, Manju; Kuttappan, Shruthy; Nair, Shantikumar; Nair, Manitha B.

2015-10-01

Porous nanohydroxyapatite (nanoHA) is a promising bone substitute, but it is brittle, which limits its utility for load bearing applications. To address this issue, herein, biodegradable electrospun microfibrous sheets of poly(L-lactic acid)-(PLLA)-polyvinyl alcohol (PVA) were incorporated into a gelatin-nanoHA matrix which was investigated for its mechanical properties, the physical integration of the fibers with the matrix, cell infiltration, osteogenic differentiation and bone regeneration. The inclusion of sacrificial fibers like PVA along with PLLA and leaching resulted in improved cellular infiltration towards the center of the scaffold. Furthermore, the treatment of PLLA fibers with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide enhanced their hydrophilicity, ensuring firm anchorage between the fibers and the gelatin-HA matrix. The incorporation of PLLA microfibers within the gelatin-nanoHA matrix reduced the brittleness of the scaffolds, the effect being proportional to the number of layers of fibrous sheets in the matrix. The proliferation and osteogenic differentiation of human adipose-derived mesenchymal stem cells was augmented on the fibrous scaffolds in comparison to those scaffolds devoid of fibers. Finally, the scaffold could promote cell infiltration, together with bone regeneration, upon implantation in a rabbit femoral cortical defect within 4 weeks. The bone regeneration potential was significantly higher when compared to commercially available HA (Surgiwear™). Thus, this biomimetic, porous, 3D composite scaffold could be offered as a promising candidate for bone regeneration in orthopedics.

Peer scaffolding in an EFL writing classroom: An investigation of writing accuracy and scaffolding behaviors

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Parastou Gholami Pasand

2017-09-01

Full Text Available Considering the tenets of Sociocultural Theory with its emphasis on co-construction of knowledge, L2 writing can be regarded as a co-writing practice whereby assistance is provided to struggling writers. To date, most studies have dealt with peer scaffolding in the revision phase of writing, as such planning and drafting are remained untouched. The present study examines the impact of peer scaffolding on writing accuracy of a group of intermediate EFL learners, and explores scaffolding behaviors employed by them in planning and drafting phases of writing. To these ends, 40 freshmen majoring in English Language and Literature in the University of Guilan were randomly divided into a control group and an experimental group consisting of dyads in which a competent writer provided scaffolding to a less competent one using the process approach to writing. Results of independent samples t-tests revealed that learners in the experimental group produced more accurate essays. Microgenetic analysis of one dyad’s talks showed that scaffolding behaviors used in planning and drafting phases of writing were more or less the same as those identified in the revision phase. These findings can be used to inform peer intervention in L2 writing classes, and assist L2 learners in conducting successful peer scaffolding in the planning and drafting phases of writing.

Validation of scaffold design optimization in bone tissue engineering: finite element modeling versus designed experiments.

Science.gov (United States)

Uth, Nicholas; Mueller, Jens; Smucker, Byran; Yousefi, Azizeh-Mitra

2017-02-21

This study reports the development of biological/synthetic scaffolds for bone tissue engineering (TE) via 3D bioplotting. These scaffolds were composed of poly(L-lactic-co-glycolic acid) (PLGA), type I collagen, and nano-hydroxyapatite (nHA) in an attempt to mimic the extracellular matrix of bone. The solvent used for processing the scaffolds was 1,1,1,3,3,3-hexafluoro-2-propanol. The produced scaffolds were characterized by scanning electron microscopy, microcomputed tomography, thermogravimetric analysis, and unconfined compression test. This study also sought to validate the use of finite-element optimization in COMSOL Multiphysics for scaffold design. Scaffold topology was simplified to three factors: nHA content, strand diameter, and strand spacing. These factors affect the ability of the scaffold to bear mechanical loads and how porous the structure can be. Twenty four scaffolds were constructed according to an I-optimal, split-plot designed experiment (DE) in order to generate experimental models of the factor-response relationships. Within the design region, the DE and COMSOL models agreed in their recommended optimal nHA (30%) and strand diameter (460 μm). However, the two methods disagreed by more than 30% in strand spacing (908 μm for DE; 601 μm for COMSOL). Seven scaffolds were 3D-bioplotted to validate the predictions of DE and COMSOL models (4.5-9.9 MPa measured moduli). The predictions for these scaffolds showed relative agreement for scaffold porosity (mean absolute percentage error of 4% for DE and 13% for COMSOL), but were substantially poorer for scaffold modulus (51% for DE; 21% for COMSOL), partly due to some simplifying assumptions made by the models. Expanding the design region in future experiments (e.g., higher nHA content and strand diameter), developing an efficient solvent evaporation method, and exerting a greater control over layer overlap could allow developing PLGA-nHA-collagen scaffolds to meet the mechanical requirements for

Biodegradable Polymer-Based Scaffolds for Bone Tissue Engineering

CERN Document Server

Sultana, Naznin

2013-01-01

This book addresses the principles, methods and applications of biodegradable polymer based scaffolds for bone tissue engineering. The general principle of bone tissue engineering is reviewed and the traditional and novel scaffolding materials, their properties and scaffold fabrication techniques are explored. By acting as temporary synthetic extracellular matrices for cell accommodation, proliferation, and differentiation, scaffolds play a pivotal role in tissue engineering. This book does not only provide the comprehensive summary of the current trends in scaffolding design but also presents the new trends and directions for scaffold development for the ever expanding tissue engineering applications.

PENGARUH E-SCAFFOLDING DALAM THINK PAIR SHARE TERHADAP KEMAMPUAN BERPIKIR TINGKAT TINGGI DINAMIKA PARTIKEL

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Akhmad Fauzul Albab

2016-01-01

Full Text Available Abstract: This study aimed to examine the effect of e-learning based Think Pair Share cooperative learning model toward higher order thinking skills of students. This study was conducted at SMAN 1 Jember for X grade students and used factorial design. Two experimental groups (TPS with E-Scaffolding and TPS with scaffolding were compared with a control group (TPS. This research was carried out to 180 students. The results showed that there is a difference in high-order thinking skills among groups of students who take the e-scaffolding in the TPS, scaffolding in TPS, and TPS learning; there is a difference in high-order thinking skills among groups of students with different prior knowledge levels; and there is no interactional effect among e-scaffolding in TPS, scaffolding in TPS and TPS strategy and the student’s prior knowledge on high order thinking skills. Key words: e-scaffolding, think pair share, high order thinking, prior knowledge.                                                                                     Abstrak: Penelitian ini bertujuan untuk menguji pengaruh pembelajaran berbasis e-learning yang terintegrasi dalam model pembelajaran kooperatif Think Pair Share (TPS dalam bentuk E-Scaffolding terhadap kemampuan berpikir tingkat tinggi siswa. Penelitian dilaksanakan di SMA Negeri 1 Jember untuk siswa kelas X ini dengan menggunakan rancangan faktorial. Dua kelompok eksperimen (TPS dengan E-Scaffolding dan TPS dengan Scaffolding dibandingkan dengan sebuah kelompok kontrol (TPS. Penelitian dilaksanakan terhadap sampel sebanyak 180 siswa yang dipilih secara acak kelompok. Hasil penelitian menunjukkan bahwa terdapat perbedaan kemampuan berpikir tingkat tinggi antara kelompok siswa yang mengikuti pembelajaran e-scaffolding dalam TPS dengan pembelajaran scaffolding dalam TPS maupun siswa dengan pembelajaran TPS; terdapat perbedaan kemampuan berpikir

The Politics of Mindfulness. A Response to "Mindfulness, Democracy, Education"

Science.gov (United States)

Comstock, Patrick W.

2015-01-01

Mindfulness is rapidly becoming a mainstream educational intervention. A growing number of schools, colleges, and universities are incorporating mindfulness into the curriculum, and while there is a substantial body of research literature in psychology attesting to the mental and physical benefits of mindfulness, critics of the movement have…

Platelet lysate embedded scaffolds for skin regeneration.

Science.gov (United States)

Sandri, Giuseppina; Bonferoni, Maria Cristina; Rossi, Silvia; Ferrari, Franca; Mori, Michela; Cervio, Marila; Riva, Federica; Liakos, Ioannis; Athanassiou, Athanassia; Saporito, Francesca; Marini, Lara; Caramella, Carla

2015-04-01

The work presents the development of acellular scaffolds extemporaneously embedded with platelet lysate (PL), as an innovative approach in the field of tissue regeneration/reparation. PL embedded scaffolds should have a tridimensional architecture to support cell migration and growth, in order to restore skin integrity. For this reason, chondroitin sulfate (CS) was associated with sodium alginate (SA) to prepare highly porous systems. The developed scaffolds were characterized for chemical stability to γ-radiation, morphology, hydration and mechanical properties. Moreover, the capability of fibroblasts and endothelial cells to populate the scaffold was evaluated by means of proliferation test 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and confocal laser scanning microscopy study. The scaffolds, not altered by sterilization, were characterized by limited swelling and high flexibility, by foam-like structure with bubbles that formed a high surface area and irregular texture suitable for cell adhesion. Cell growth and scaffold population were evident on the bubble surface, where the cells appeared anchored to the scaffold structure. Scaffold network based on CS and SA demonstrated to be an effective support to enhance and to allow fibroblasts and endothelial cells (human umbilical vein endothelial cells, HUVEC) adhesion and proliferation. In particular, it could be hypothesized that cell adhesion was facilitated by the synergic effect of PL and CS. Although further in vivo evaluation is needed, on the basis of in vitro results, PL embedded scaffolds seem promising systems for skin wound healing.

Semiotic Scaffolding in Mathematics

DEFF Research Database (Denmark)

Johansen, Mikkel Willum; Misfeldt, Morten

2015-01-01

This paper investigates the notion of semiotic scaffolding in relation to mathematics by considering its influence on mathematical activities, and on the evolution of mathematics as a research field. We will do this by analyzing the role different representational forms play in mathematical...... cognition, and more broadly on mathematical activities. In the main part of the paper, we will present and analyze three different cases. For the first case, we investigate the semiotic scaffolding involved in pencil and paper multiplication. For the second case, we investigate how the development of new...... in both mathematical cognition and in the development of mathematics itself, but mathematical cognition cannot itself be reduced to the use of semiotic scaffolding....

Understanding the role of mind wandering in stress-related working memory impairments.

Science.gov (United States)

Banks, Jonathan B; Boals, Adriel

2017-08-01

Mind wandering has been identified as a possible cause for stress-related working memory (WM) task impairments following laboratory stressors. The current study attempted to induce mind wandering regarding negative, positive, or neutral events using an expressive writing task and examined the impact on WM task performance. We examined the role of mind wandering in understanding the impact of life stress on WM. Additionally, we explored the role of thought suppression on the relationship between mind wandering and WM. One hundred and fifty participants completed WM measures before (Time 1) and after (Time 2) the writing manipulation. The writing manipulation did not alter mind wandering or WM task performance. Time 1 WM predicted mind wandering during the Time 2 WM task, which subsequently predicted poorer Time 2 WM task performance. The impact of daily life stress on WM was mediated by mind wandering. Trait levels of thought suppression moderated the impact of mind wandering on WM. Specifically, higher levels of suppression resulted in stronger negative impact of mind wandering on WM task performance. Findings are discussed in terms of the impact of mind wandering on WM task performance.

Fluorescent composite scaffolds made of nanodiamonds/polycaprolactone

Science.gov (United States)

Cao, Li; Hou, Yanwen; Lafdi, Khalid; Urmey, Kirk

2015-11-01

Polycaprolactone (PCL) has been widely studied for biological applications. Biodegradable PCL fibrous scaffold can work as an appropriate substrate for tissue regeneration. In this letter, fluorescent nanodiamonds (FNDs) were prepared after surface passivation with octadecylamine. The FNDs were then mixed with PCL polymer and subsequently electrospun into FNDs/PCL fibrous scaffolds. The obtained scaffolds not only exhibited photoluminescence, but also showed reinforced mechanical strength. Toxicity study indicated FNDs/PCL scaffolds were nontoxic. This biocompatible fluorescent composite fibrous scaffold can support in vitro cell growth and also has the potential to act as an optical probe for tissue engineering application in vitro and in vivo.

Can mind-wandering be timeless? Atemporal focus and aging in mind-wandering paradigms

Directory of Open Access Journals (Sweden)

Jonathan David Jackson

2013-10-01

Full Text Available Recent research has examined how often mind-wandering occurs about past versus future events. However, mind-wandering may also be atemporal, although previous investigations of this possibility have not yielded consistent results. Indeed, it is unclear what proportion of mind-wandering is atemporal, and also how an atemporal response option would affect the future oriented bias often reported during low-demand tasks used to measure mind-wandering. The present study examined self-reported (Experiment 1 and probe-caught (Experiment 2 mind-wandering using the low-demand Sustained Attention to Response Task (SART in younger (18-30 and older (50-73 adults in an experimental paradigm developed to measure mind-wandering in a sample using Amazon’s Mechanical Turk. Across self-reported and probe-caught mind-wandering, the atemporal response option was used at least as frequently as past or future mind-wandering options. Although older adults reported far fewer mind-wandering events, they showed a very similar temporal pattern to younger adults. Most importantly, inclusion of the atemporal report option affected performance on the SART and selectively eliminated the prospective bias in self-reported mind-wandering, but not in probe-caught mind-wandering. These results suggest that both young and older participants are often not thinking of past or future events when mind-wandering, but are thinking of events that cannot easily be categorized as either.

In Vivo Evaluation of a Novel Oriented Scaffold-BMSC Construct for Enhancing Full-Thickness Articular Cartilage Repair in a Rabbit Model.

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Shuaijun Jia

Full Text Available Tissue engineering (TE has been proven usefulness in cartilage defect repair. For effective cartilage repair, the structural orientation of the cartilage scaffold should mimic that of native articular cartilage, as this orientation is closely linked to cartilage mechanical functions. Using thermal-induced phase separation (TIPS technology, we have fabricated an oriented cartilage extracellular matrix (ECM-derived scaffold with a Young's modulus value 3 times higher than that of a random scaffold. In this study, we test the effectiveness of bone mesenchymal stem cell (BMSC-scaffold constructs (cell-oriented and random in repairing full-thickness articular cartilage defects in rabbits. While histological and immunohistochemical analyses revealed efficient cartilage regeneration and cartilaginous matrix secretion at 6 and 12 weeks after transplantation in both groups, the biochemical properties (levels of DNA, GAG, and collagen and biomechanical values in the oriented scaffold group were higher than that in random group at early time points after implantation. While these differences were not evident at 24 weeks, the biochemical and biomechanical properties of the regenerated cartilage in the oriented scaffold-BMSC construct group were similar to that of native cartilage. These results demonstrate that an oriented scaffold, in combination with differentiated BMSCs can successfully repair full-thickness articular cartilage defects in rabbits, and produce cartilage enhanced biomechanical properties.

The Association of Parent Mindfulness with Parenting and Youth Psychopathology Across Three Developmental Stages.

Science.gov (United States)

Parent, Justin; McKee, Laura G; N Rough, Jennifer; Forehand, Rex

2016-01-01

The primary purpose of the current study was to test a model examining the process by which parent dispositional mindfulness relates to youth psychopathology through mindful parenting and parenting practices. The universality of the model across youth at three developmental stages was examined: young childhood (3-7 years; n = 210), middle childhood (8-12 years; n = 200), and adolescence (13-17 years; n = 205). Overall, participants were 615 parents (55% female) and one of their 3-to-17 year old children (45% female). Parents reported on their dispositional mindfulness, mindful parenting, positive and negative parenting practices and their child's or adolescent's internalizing and externalizing problems. Consistent findings across all three developmental stages indicated that higher levels of parent dispositional mindfulness were indirectly related to lower levels of youth internalizing and externalizing problems through higher levels of mindful parenting and lower levels of negative parenting practices. Replication of these findings across families with children at different developmental stages lends support to the generalizability of the model.

[Strategies to choose scaffold materials for tissue engineering].

Science.gov (United States)

Gao, Qingdong; Zhu, Xulong; Xiang, Junxi; Lü, Yi; Li, Jianhui

2016-02-01

Current therapies of organ failure or a wide range of tissue defect are often not ideal. Transplantation is the only effective way for long time survival. But it is hard to meet huge patients demands because of donor shortage, immune rejection and other problems. Tissue engineering could be a potential option. Choosing a suitable scaffold material is an essential part of it. According to different sources, tissue engineering scaffold materials could be divided into three types which are natural and its modified materials, artificial and composite ones. The purpose of tissue engineering scaffold is to repair the tissues or organs damage, so could reach the ideal recovery in its function and structure aspect. Therefore, tissue engineering scaffold should even be as close as much to the original tissue or organs in function and structure. We call it "organic scaffold" and this strategy might be the drastic perfect substitute for the tissues or organs in concern. Optimized organization with each kind scaffold materials could make up for biomimetic structure and function of the tissue or organs. Scaffold material surface modification, optimized preparation procedure and cytosine sustained-release microsphere addition should be considered together. This strategy is expected to open new perspectives for tissue engineering. Multidisciplinary approach including material science, molecular biology, and engineering might find the most ideal tissue engineering scaffold. Using the strategy of drawing on each other strength and optimized organization with each kind scaffold material to prepare a multifunctional biomimetic tissue engineering scaffold might be a good method for choosing tissue engineering scaffold materials. Our research group had differentiated bone marrow mesenchymal stem cells into bile canaliculi like cells. We prepared poly(L-lactic acid)/poly(ε-caprolactone) biliary stent. The scaffold's internal played a part in the long-term release of cytokines which

Nano-ceramic composite scaffolds for bioreactor-based bone engineering.

Science.gov (United States)

Lv, Qing; Deng, Meng; Ulery, Bret D; Nair, Lakshmi S; Laurencin, Cato T

2013-08-01

Composites of biodegradable polymers and bioactive ceramics are candidates for tissue-engineered scaffolds that closely match the properties of bone. We previously developed a porous, three-dimensional poly (D,L-lactide-co-glycolide) (PLAGA)/nanohydroxyapatite (n-HA) scaffold as a potential bone tissue engineering matrix suitable for high-aspect ratio vessel (HARV) bioreactor applications. However, the physical and cellular properties of this scaffold are unknown. The present study aims to evaluate the effect of n-HA in modulating PLAGA scaffold properties and human mesenchymal stem cell (HMSC) responses in a HARV bioreactor. By comparing PLAGA/n-HA and PLAGA scaffolds, we asked whether incorporation of n-HA (1) accelerates scaffold degradation and compromises mechanical integrity; (2) promotes HMSC proliferation and differentiation; and (3) enhances HMSC mineralization when cultured in HARV bioreactors. PLAGA/n-HA scaffolds (total number = 48) were loaded into HARV bioreactors for 6 weeks and monitored for mass, molecular weight, mechanical, and morphological changes. HMSCs were seeded on PLAGA/n-HA scaffolds (total number = 38) and cultured in HARV bioreactors for 28 days. Cell migration, proliferation, osteogenic differentiation, and mineralization were characterized at four selected time points. The same amount of PLAGA scaffolds were used as controls. The incorporation of n-HA did not alter the scaffold degradation pattern. PLAGA/n-HA scaffolds maintained their mechanical integrity throughout the 6 weeks in the dynamic culture environment. HMSCs seeded on PLAGA/n-HA scaffolds showed elevated proliferation, expression of osteogenic phenotypic markers, and mineral deposition as compared with cells seeded on PLAGA scaffolds. HMSCs migrated into the scaffold center with nearly uniform cell and extracellular matrix distribution in the scaffold interior. The combination of PLAGA/n-HA scaffolds with HMSCs in HARV bioreactors may allow for the generation of engineered

The role of mindfulness and spiritual intelligence in students' mental health

Directory of Open Access Journals (Sweden)

Ebrahim Nemati

2017-06-01

Full Text Available Studies show that mental disorders are highly prevalent among students. Therefore, the present study aimed to examine the role of mindfulness and spiritual intelligence in the students’ mental health studying at university of medical sciences. The study population included all undergraduate and medicine students. A total of 393 female and male students (193 medical and 200 non-medical students were selected through randomly. General Health Questionnaire (GHQ and spiritual intelligence and mindfulness questionnaire were used to evaluate the participants. The results revealed the negative correlation of mental health with mindfulness and spiritual intelligence and a positive correlation between mindfulness and dimensions of spiritual intelligence. Also, the dimension of spiritual life (43.1% and mindfulness (31% had a significant negative effect on the explained variance of the students’ mental health. Analysis of variance showed that the scales of mindfulness, perception of existence, somatic symptoms, and anxiety were higher among women. Therefore, the students can be more capable of coping with existing traumas and pressures by boosting their spirituality, consciousness, and mindfulness.

Binary phase solid-state photopolymerization of acrylates: design, characterization and biomineralization of 3D scaffolds for tissue engineering

Science.gov (United States)

Maitlo, Inamullah; Ali, Safdar; Akram, Muhammad Yasir; Shehzad, Farooq Khurum; Nie, Jun

2017-12-01

Porous polymer scaffolds designed by the cryogel method are attractive materials for a range of tissue engineering applications. However, the use of toxic crosslinker for retaining the pore structure limits their clinical applications. In this research, acrylates (HEA/PEGDA, HEMA/PEGDA and PEGDA) were used in the low-temperature solid-state photopolymerization to produce porous scaffolds with good structural retention. The morphology, pore diameter, mineral deposition and water absorption of the scaffold were characterized by SEM and water absorption test respectively. Elemental analysis and cytotoxicity of the biomineralized scaffold were revealed by using XRD and MTT assay test. The PEGDA-derived scaffold showed good water absorption ability and a higher degree of porosity with larger pore size compared to others. XRD patterns and IR results confirmed the formation of hydroxyapatite crystals from an alternative socking process. The overall cell proliferation was excellent, where PEGDA-derived scaffold had the highest and the most uniform cell growth, while HEMA/PEGDA scaffold showed the least. These results suggest that the cell proliferation and adhesion are directly proportional to the pore size, the shape and the porosity of scaffolds.

Mag-seeding of rat bone marrow stromal cells into porous hydroxyapatite scaffolds for bone tissue engineering.

Science.gov (United States)

Shimizu, Kazunori; Ito, Akira; Honda, Hiroyuki

2007-09-01

Bone tissue engineering has been investigated as an alternative strategy for autograft transplantation. In the process of tissue engineering, cell seeding into three-dimensional (3-D) scaffolds is the first step for constructing 3-D tissues. We have proposed a methodology of cell seeding into 3-D porous scaffolds using magnetic force and magnetite nanoparticles, which we term Mag-seeding. In this study, we applied this Mag-seeding technique to bone tissue engineering using bone marrow stromal cells (BMSCs) and 3-D hydroxyapatite (HA) scaffolds. BMSCs were magnetically labeled with our original magnetite cationic liposomes (MCLs) having a positive surface charge to improve adsorption to cell surface. Magnetically labeled BMSCs were seeded onto a scaffold, and a 1-T magnet was placed under the scaffold. By using Mag-seeding, the cells were successfully seeded into the internal space of scaffolds with a high cell density. The cell seeding efficiency into HA scaffolds by Mag-seeding was approximately threefold larger than that by static-seeding (conventional method, without a magnet). After a 14-d cultivation period using the osteogenic induction medium by Mag-seeding, the level of two representative osteogenic markers (alkaline phosphatase and osteocalcin) were significantly higher than those by static-seeding. These results indicated that Mag-seeding of BMSCs into HA scaffolds is an effective approach to bone tissue engineering.

A radiopaque electrospun scaffold for engineering fibrous musculoskeletal tissues: Scaffold characterization and in vivo applications.

Science.gov (United States)

Martin, John T; Milby, Andrew H; Ikuta, Kensuke; Poudel, Subash; Pfeifer, Christian G; Elliott, Dawn M; Smith, Harvey E; Mauck, Robert L

2015-10-01

Tissue engineering strategies have emerged in response to the growing prevalence of chronic musculoskeletal conditions, with many of these regenerative methods currently being evaluated in translational animal models. Engineered replacements for fibrous tissues such as the meniscus, annulus fibrosus, tendons, and ligaments are subjected to challenging physiologic loads, and are difficult to track in vivo using standard techniques. The diagnosis and treatment of musculoskeletal conditions depends heavily on radiographic assessment, and a number of currently available implants utilize radiopaque markers to facilitate in vivo imaging. In this study, we developed a nanofibrous scaffold in which individual fibers included radiopaque nanoparticles. Inclusion of radiopaque particles increased the tensile modulus of the scaffold and imparted radiation attenuation within the range of cortical bone. When scaffolds were seeded with bovine mesenchymal stem cells in vitro, there was no change in cell proliferation and no evidence of promiscuous conversion to an osteogenic phenotype. Scaffolds were implanted ex vivo in a model of a meniscal tear in a bovine joint and in vivo in a model of total disc replacement in the rat coccygeal spine (tail), and were visualized via fluoroscopy and microcomputed tomography. In the disc replacement model, histological analysis at 4 weeks showed that the scaffold was biocompatible and supported the deposition of fibrous tissue in vivo. Nanofibrous scaffolds that include radiopaque nanoparticles provide a biocompatible template with sufficient radiopacity for in vivo visualization in both small and large animal models. This radiopacity may facilitate image-guided implantation and non-invasive long-term evaluation of scaffold location and performance. The healing capacity of fibrous musculoskeletal tissues is limited, and injury or degeneration of these tissues compromises the standard of living of millions in the US. Tissue engineering repair

Polycaprolactone nanofiber interspersed collagen type-I scaffold for bone regeneration: a unique injectable osteogenic scaffold

International Nuclear Information System (INIS)

Baylan, Nuray; Ditto, Maggie; Lawrence, Joseph G; Yildirim-Ayan, Eda; Bhat, Samerna; Lecka-Czernik, Beata

2013-01-01

There is an increasing demand for an injectable cell coupled three-dimensional (3D) scaffold to be used as bone fracture augmentation material. To address this demand, a novel injectable osteogenic scaffold called PN-COL was developed using cells, a natural polymer (collagen type-I), and a synthetic polymer (polycaprolactone (PCL)). The injectable nanofibrous PN-COL is created by interspersing PCL nanofibers within pre-osteoblast cell embedded collagen type-I. This simple yet novel and powerful approach provides a great benefit as an injectable bone scaffold over other non-living bone fracture stabilization polymers, such as polymethylmethacrylate and calcium content resin-based materials. The advantages of injectability and the biomimicry of collagen was coupled with the structural support of PCL nanofibers, to create cell encapsulated injectable 3D bone scaffolds with intricate porous internal architecture and high osteoconductivity. The effects of PCL nanofiber inclusion within the cell encapsulated collagen matrix has been evaluated for scaffold size retention and osteocompatibility, as well as for MC3T3-E1 cells osteogenic activity. The structural analysis of novel bioactive material proved that the material is chemically stable enough in an aqueous solution for an extended period of time without using crosslinking reagents, but it is also viscous enough to be injected through a syringe needle. Data from long-term in vitro proliferation and differentiation data suggests that novel PN-COL scaffolds promote the osteoblast proliferation, phenotype expression, and formation of mineralized matrix. This study demonstrates for the first time the feasibility of creating a structurally competent, injectable, cell embedded bone tissue scaffold. Furthermore, the results demonstrate the advantages of mimicking the hierarchical architecture of native bone with nano- and micro-size formation through introducing PCL nanofibers within macron-size collagen fibers and in

BESST--efficient scaffolding of large fragmented assemblies.

Science.gov (United States)

Sahlin, Kristoffer; Vezzi, Francesco; Nystedt, Björn; Lundeberg, Joakim; Arvestad, Lars

2014-08-15

The use of short reads from High Throughput Sequencing (HTS) techniques is now commonplace in de novo assembly. Yet, obtaining contiguous assemblies from short reads is challenging, thus making scaffolding an important step in the assembly pipeline. Different algorithms have been proposed but many of them use the number of read pairs supporting a linking of two contigs as an indicator of reliability. This reasoning is intuitive, but fails to account for variation in link count due to contig features.We have also noted that published scaffolders are only evaluated on small datasets using output from only one assembler. Two issues arise from this. Firstly, some of the available tools are not well suited for complex genomes. Secondly, these evaluations provide little support for inferring a software's general performance. We propose a new algorithm, implemented in a tool called BESST, which can scaffold genomes of all sizes and complexities and was used to scaffold the genome of P. abies (20 Gbp). We performed a comprehensive comparison of BESST against the most popular stand-alone scaffolders on a large variety of datasets. Our results confirm that some of the popular scaffolders are not practical to run on complex datasets. Furthermore, no single stand-alone scaffolder outperforms the others on all datasets. However, BESST fares favorably to the other tested scaffolders on GAGE datasets and, moreover, outperforms the other methods when library insert size distribution is wide. We conclude from our results that information sources other than the quantity of links, as is commonly used, can provide useful information about genome structure when scaffolding.

In vitro study on the degradation of lithium-doped hydroxyapatite for bone tissue engineering scaffold

Energy Technology Data Exchange (ETDEWEB)

Wang, Yaping; Yang, Xu; Gu, Zhipeng; Qin, Huanhuan [College of Polymer Science and Engineering, Sichuan University, Chengdu 610065 (China); Li, Li [Department of Oncology, The 452 Hospital of Chinese PLA, Chengdu, Sichuan Province 610021 (China); Liu, Jingwang [College of Polymer Science and Engineering, Sichuan University, Chengdu 610065 (China); Yu, Xixun, E-mail: yuxixun@163.com [College of Polymer Science and Engineering, Sichuan University, Chengdu 610065 (China)

2016-09-01

HA scaffolds. - Highlights: • A bone-like apatite layer with bioactivity was formed on the surfaces of LiHA scaffolds. • LiHA scaffolds showed a higher degradation trend than pure HA scaffolds in osteoblast-mediated degradation in vitro. • LiHA scaffolds were beneficial to the proliferation of osteoblasts.

Physicochemical properties and enhanced cellullar responses of biocompatible polymeric scaffolds treated with atmospheric pressure plasma using O2 gas

International Nuclear Information System (INIS)

Lee, Hyun-Uk; Park, So-Young; Kang, Yoon-Hee; Jeong, Se-Young; Choi, Sae-Hae; Jahng, Yoon-Young; Chung, Gook-Hyun; Kim, Moon-Bum; Cho, Chae-Ryong

2011-01-01

Biocompatible polymeric scaffolds were fabricated by mixing 5 wt.% poly(ε-caprolactone) (P) with 4 wt.% gelatin (G) and 1.6 wt.% Dulbecco's modified Eagle's medium containing 10% fetal bovine serum (D). These PGD scaffolds were also treated with atmospheric pressure (AP) plasma using O 2 reactive gas (to create O-PGD scaffolds). The physicochemical and mechanical properties of the PGD scaffolds were characterized by in vitro biodegradability tests, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, contact angle measurements, and tensile strength measurements. The wettability and hydrophilic properties of the scaffold surface were improved remarkably by adding G and D to P, and by subsequent oxygen-assisted AP plasma treatment. An MTT assay, a cell attachment efficiency assay, scanning electron microscopy, and confocal microscopy revealed that Chinese Hamster Ovary (CHO)-K1 cells exhibited higher cell attachment and viability on the PGD and O-PGD scaffolds than on the P and PG scaffolds. Furthermore, the long-term viability of the CHO cells on the PGD and O-PGD scaffolds without exchanging the cell culture media was significantly improved compared to their viability on the P and PG scaffolds. Overall, the PGD and O-PGD scaffolds are expected to be useful as cell growth supporting biomaterials in tissue engineering.

Mindfulness

DEFF Research Database (Denmark)

Agger Nielsen, Jeppe; Nielsen, Charlotte Agger

2013-01-01

Mindfulness har de senere år budt sig til som effektiv hjælp til selvhjælp for fortravlede ledere og professionelle. Men er meditationsøvelser og forsøg på at finde indre ”zen”-ro overhovedet lederens anstrengelser værd? Denne artikel diskuterer effekterne af mindfulness og giver ordet til såvel...

[Three-dimensional parallel collagen scaffold promotes tendon extracellular matrix formation].

Science.gov (United States)

Zheng, Zefeng; Shen, Weiliang; Le, Huihui; Dai, Xuesong; Ouyang, Hongwei; Chen, Weishan

2016-03-01

To investigate the effects of three-dimensional parallel collagen scaffold on the cell shape, arrangement and extracellular matrix formation of tendon stem cells. Parallel collagen scaffold was fabricated by unidirectional freezing technique, while random collagen scaffold was fabricated by freeze-drying technique. The effects of two scaffolds on cell shape and extracellular matrix formation were investigated in vitro by seeding tendon stem/progenitor cells and in vivo by ectopic implantation. Parallel and random collagen scaffolds were produced successfully. Parallel collagen scaffold was more akin to tendon than random collagen scaffold. Tendon stem/progenitor cells were spindle-shaped and unified orientated in parallel collagen scaffold, while cells on random collagen scaffold had disorder orientation. Two weeks after ectopic implantation, cells had nearly the same orientation with the collagen substance. In parallel collagen scaffold, cells had parallel arrangement, and more spindly cells were observed. By contrast, cells in random collagen scaffold were disorder. Parallel collagen scaffold can induce cells to be in spindly and parallel arrangement, and promote parallel extracellular matrix formation; while random collagen scaffold can induce cells in random arrangement. The results indicate that parallel collagen scaffold is an ideal structure to promote tendon repairing.

Scaffolding for motivation by parents, and child homework motivations and emotions: Effects of a training programme.

Science.gov (United States)

Moè, Angelica; Katz, Idit; Alesi, Marianna

2018-06-01

Based on the principles of scaffolding for motivation and on the assumptions of self-determination theory, two studies aimed to assess the role played by perceived parental autonomy-supportive scaffolding on child homework autonomous motivation, self-efficacy, affect, and engagement. The results of Study 1, which involved 122 parents and their children, showed that the higher the parental autonomous motivation, the more their children perceived them as autonomy-supportive while scaffolding for motivation, and hence developed autonomous motivation, self-efficacy, and engagement in homework. In Study 2, 37 parents were involved in a four-session training programme that focused on sustaining autonomy-supportive scaffolding modalities. The training decreased parental negative affect, prevented child negative affect increase, and maintained child homework motivation. The discussion focuses on the strength that parents have with regard to helping their children develop less negative, and potentially also more positive attitude towards homework, through autonomy support as a scaffold for motivation. © 2018 The British Psychological Society.

Biocomposite scaffolds for bone regeneration: Role of chitosan and hydroxyapatite within poly-3-hydroxybutyrate-co-3-hydroxyvalerate on mechanical properties and in vitro evaluation.

Science.gov (United States)

Zhang, Sai; Prabhakaran, Molamma P; Qin, Xiaohong; Ramakrishna, Seeram

2015-11-01

Bio-engineered scaffolds for bone tissue regeneration is an exploding area of research mainly because they can satisfy the essential demands and current challenges in bone replacement therapies, by imitating the extracellular matrix (ECM) of the native bone. We fabricated bio-composite nanofibrous scaffolds with a blend of poly-3-hydroxybutyrate-co-3-hydroxyvalerate (PHBV), chitosan (CTS) and hydroxyapatite (HA) during this study. Morphological evaluation confirmed the fiber diameters of PHBV, PHBV/CTS (90:10), PHBV/CTS/HA4 (85.5:9.5:5) and PHBV/CTS/HA8 (81:9:10) as 405 ± 74 nm, 334 ± 82 nm, 316 ± 103 nm and 256 ± 110 nm, respectively. The PHBV/CTS/HA4 and PHBV/CTS/HA8 scaffolds were capable of enduring the long term culture of human fetal osteoblasts (hFOB) with ultimate tensile strength of 3.55 ± 0.22 MPa and 4.19 ± 0.19 MPa, respectively. The proliferation of osteoblasts on PHBV/CTS/HA8 scaffold was found 34.10% higher than that on PHBV scaffold on day 20. Cell maturation identified by alkaline phosphatase activity on day 20 was significantly higher on PHBV/CTS/HA8 scaffold than that on PHBV scaffold. The cells on PHBV/CTS/HA8 scaffold also acquired higher mineral deposition (25.79%) than the mineral deposition on PHBV scaffold by day 20, confirmed by EDX analysis. Based on the results, we concluded that the electrospun PHBV/CTS/HA8 scaffolds hold great potential to promote the regeneration of bone tissue due to the synergistic effect of chitosan and HA, whereby chitosan provided cell recognition sites while HA acted as a chelating agent for organizing the apatite-like mineralization. Copyright © 2015 Elsevier Ltd. All rights reserved.

Inverse Opal Scaffolds and Their Biomedical Applications.

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Zhang, Yu Shrike; Zhu, Chunlei; Xia, Younan

2017-09-01

Three-dimensional porous scaffolds play a pivotal role in tissue engineering and regenerative medicine by functioning as biomimetic substrates to manipulate cellular behaviors. While many techniques have been developed to fabricate porous scaffolds, most of them rely on stochastic processes that typically result in scaffolds with pores uncontrolled in terms of size, structure, and interconnectivity, greatly limiting their use in tissue regeneration. Inverse opal scaffolds, in contrast, possess uniform pores inheriting from the template comprised of a closely packed lattice of monodispersed microspheres. The key parameters of such scaffolds, including architecture, pore structure, porosity, and interconnectivity, can all be made uniform across the same sample and among different samples. In conjunction with a tight control over pore sizes, inverse opal scaffolds have found widespread use in biomedical applications. In this review, we provide a detailed discussion on this new class of advanced materials. After a brief introduction to their history and fabrication, we highlight the unique advantages of inverse opal scaffolds over their non-uniform counterparts. We then showcase their broad applications in tissue engineering and regenerative medicine, followed by a summary and perspective on future directions. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Post Processing and Biological Evaluation of the Titanium Scaffolds for Bone Tissue Engineering

Directory of Open Access Journals (Sweden)

Bartłomiej Wysocki

2016-03-01

Full Text Available Nowadays, post-surgical or post-accidental bone loss can be substituted by custom-made scaffolds fabricated by additive manufacturing (AM methods from metallic powders. However, the partially melted powder particles must be removed in a post-process chemical treatment. The aim of this study was to investigate the effect of the chemical polishing with various acid baths on novel scaffolds’ morphology, porosity and mechanical properties. In the first stage, Magics software (Materialise NV, Leuven, Belgium was used to design a porous scaffolds with pore size equal to (A 200 µm, (B 500 µm and (C 200 + 500 µm, and diamond cell structure. The scaffolds were fabricated from commercially pure titanium powder (CP Ti using a SLM50 3D printing machine (Realizer GmbH, Borchen, Germany. The selective laser melting (SLM process was optimized and the laser beam energy density in range of 91–151 J/mm3 was applied to receive 3D structures with fully dense struts. To remove not fully melted titanium particles the scaffolds were chemically polished using various HF and HF-HNO3 acid solutions. Based on scaffolds mass loss and scanning electron (SEM observations, baths which provided most uniform surface cleaning were proposed for each porosity. The pore and strut size after chemical treatments was calculated based on the micro-computed tomography (µ-CT and SEM images. The mechanical tests showed that the treated scaffolds had Young’s modulus close to that of compact bone. Additionally, the effect of pore size of chemically polished scaffolds on cell retention, proliferation and differentiation was studied using human mesenchymal stem cells. Small pores yielded higher cell retention within the scaffolds, which then affected their growth. This shows that in vitro cell performance can be controlled to certain extent by varying pore sizes.

Design of a Novel Two-Component Hybrid Dermal Scaffold for the Treatment of Pressure Sores.

Science.gov (United States)

Sharma, Vaibhav; Kohli, Nupur; Moulding, Dale; Afolabi, Halimat; Hook, Lilian; Mason, Chris; García-Gareta, Elena

2017-11-01

The aim of this study is to design a novel two-component hybrid scaffold using the fibrin/alginate porous hydrogel Smart Matrix combined to a backing layer of plasma polymerized polydimethylsiloxane (Sil) membrane to make the fibrin-based dermal scaffold more robust for the treatment of the clinically challenging pressure sores. A design criteria are established, according to which the Sil membranes are punched to avoid collection of fluid underneath. Manual peel test shows that native silicone does not attach to the fibrin/alginate component while the plasma polymerized silicone membranes are firmly bound to fibrin/alginate. Structural characterization shows that the fibrin/alginate matrix is intact after the addition of the Sil membrane. By adding a Sil membrane to the original fibrin/alginate scaffold, the resulting two-component scaffolds have a significantly higher shear or storage modulus G'. In vitro cell studies show that dermal fibroblasts remain viable, proliferate, and infiltrate the two-component hybrid scaffolds during the culture period. These results show that the design of a novel two-component hybrid dermal scaffold is successful according to the proposed design criteria. To the best of the authors' knowledge, this is the first study that reports the combination of a fibrin-based scaffold with a plasma-polymerized silicone membrane. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Bio-functionalized PCL nanofibrous scaffolds for nerve tissue engineering

International Nuclear Information System (INIS)

Ghasemi-Mobarakeh, Laleh; Prabhakaran, Molamma P.; Morshed, Mohammad; Nasr-Esfahani, Mohammad Hossein; Ramakrishna, S.

2010-01-01

Surface properties of scaffolds such as hydrophilicity and the presence of functional groups on the surface of scaffolds play a key role in cell adhesion, proliferation and migration. Different modification methods for hydrophilicity improvement and introduction of functional groups on the surface of scaffolds have been carried out on synthetic biodegradable polymers, for tissue engineering applications. In this study, alkaline hydrolysis of poly (ε-caprolactone) (PCL) nanofibrous scaffolds was carried out for different time periods (1 h, 4 h and 12 h) to increase the hydrophilicity of the scaffolds. The formation of reactive groups resulting from alkaline hydrolysis provides opportunities for further surface functionalization of PCL nanofibrous scaffolds. Matrigel was attached covalently on the surface of an optimized 4 h hydrolyzed PCL nanofibrous scaffolds and additionally the fabrication of blended PCL/matrigel nanofibrous scaffolds was carried out. Chemical and mechanical characterization of nanofibrous scaffolds were evaluated using attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, contact angle, scanning electron microscopy (SEM) and tensile measurement. In vitro cell adhesion and proliferation study was carried out after seeding nerve precursor cells (NPCs) on different scaffolds. Results of cell proliferation assay and SEM studies showed that the covalently functionalized PCL/matrigel nanofibrous scaffolds promote the proliferation and neurite outgrowth of NPCs compared to PCL and hydrolyzed PCL nanofibrous scaffolds, providing suitable substrates for nerve tissue engineering.

Spiral-structured, nanofibrous, 3D scaffolds for bone tissue engineering.

Science.gov (United States)

Wang, Junping; Valmikinathan, Chandra M; Liu, Wei; Laurencin, Cato T; Yu, Xiaojun

2010-05-01

Polymeric nanofiber matrices have already been widely used in tissue engineering. However, the fabrication of nanofibers into complex three-dimensional (3D) structures is restricted due to current manufacturing techniques. To overcome this limitation, we have incorporated nanofibers onto spiral-structured 3D scaffolds made of poly (epsilon-caprolactone) (PCL). The spiral structure with open geometries, large surface areas, and porosity will be helpful for improving nutrient transport and cell penetration into the scaffolds, which are otherwise limited in conventional tissue-engineered scaffolds for large bone defects repair. To investigate the effect of structure and fiber coating on the performance of the scaffolds, three groups of scaffolds including cylindrical PCL scaffolds, spiral PCL scaffolds (without fiber coating), and spiral-structured fibrous PCL scaffolds (with fiber coating) have been prepared. The morphology, porosity, and mechanical properties of the scaffolds have been characterized. Furthermore, human osteoblast cells are seeded on these scaffolds, and the cell attachment, proliferation, differentiation, and mineralized matrix deposition on the scaffolds are evaluated. The results indicated that the spiral scaffolds possess porosities within the range of human trabecular bone and an appropriate pore structure for cell growth, and significantly lower compressive modulus and strength than cylindrical scaffolds. When compared with the cylindrical scaffolds, the spiral-structured scaffolds demonstrated enhanced cell proliferation, differentiation, and mineralization and allowed better cellular growth and penetration. The incorporation of nanofibers onto spiral scaffolds further enhanced cell attachment, proliferation, and differentiation. These studies suggest that spiral-structured nanofibrous scaffolds may serve as promising alternatives for bone tissue engineering applications. Copyright 2009 Wiley Periodicals, Inc.

Fabrication and characterization of hydrothermal cross-linked chitosan porous scaffolds for cartilage tissue engineering applications.

Science.gov (United States)

Shamekhi, Mohammad Amin; Rabiee, Ahmad; Mirzadeh, Hamid; Mahdavi, Hamid; Mohebbi-Kalhori, Davod; Baghaban Eslaminejad, Mohamadreza

2017-11-01

The use of various chemical cross-linking agents for the improvement of scaffolds physical and mechanical properties is a common practical method, which is limited by cytotoxicity effects. Due to exerting contract type forces, chondrocytes are known to implement shrinkage on the tissue engineered constructs, which can be avoided by the scaffold cross-linking. In the this research, chitosan scaffolds are cross-linked with hydrothermal treatment with autoclave sterilization time of 0, 10, 20 and 30min, to avoid the application of the traditional chemical toxic materials. The optimization studies with gel content and crosslink density measurements indicate that for 20min sterilization time, the gel content approaches to ~80%. The scaffolds are fully characterized by the conventional techniques such as SEM, porosity and permeability, XRD, compression, thermal analysis and dynamic mechanical thermal analysis (DMTA). FT-IR studies shows that autoclave inter-chain cross-linking reduces the amine group absorption at 1560cm -1 and increase the absorption of N-acetylated groups at 1629cm -1 . It is anticipated, that this observation evidenced by chitosan scaffold browning upon autoclave cross-linking is an indication of the familiar maillard reaction between amine moieties and carbonyl groups. The biodegradation rate analysis shows that chitosan scaffolds with lower concentrations, possess suitable degradation rate for cartilage tissue engineering applications. In addition, cytotoxicity analysis shows that fabricated scaffolds are biocompatible. The human articular chondrocytes seeding into 3D cross-linked scaffolds shows a higher viability and proliferation in comparison with the uncross-linked samples and 2D controls. Investigation of cell morphology on the scaffolds by SEM, shows a more spherical morphology of chondrocytes on the cross-linked scaffolds for 21days of in vitro culture. Copyright © 2017. Published by Elsevier B.V.

Preparation of bioactive porous HA/PCL composite scaffolds

Energy Technology Data Exchange (ETDEWEB)

Zhao, J.; Guo, L.Y.; Yang, X.B. [Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China); Weng, J. [Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China)], E-mail: jweng@swjtu.cn

2008-12-30

Porous hydroxyapatite (HA) bioceramic scaffold has been widely attracted the attention to act as a three-dimensional (3D) template for cell adhesion, proliferation, differentiation and thus promoting bone and cartilage regeneration because of its osteoinduction. However, the porous bioceramic scaffold is fragile so that it is not suitable to be applied in clinic for bone repair or replacement. Therefore, it is significant to improve the mechanical property of porous HA bioceramics while the interconnected structure is maintained for tissue ingrowth in vivo. In the present research, a porous composite scaffold composed of HA scaffold and polycaprolactone (PCL) lining was fabricated by the method of polymer impregnating to produce HA scaffold coated with PCL lining. Subsequently, the composite scaffolds were deposited with biomimetic coating for improving the bioactivity. The HA/PCL composite scaffolds with improved mechanical property and bioactivity is expected to be a promising bone substitute in tissue engineering applications.

Polyelectrolyte-complex nanostructured fibrous scaffolds for tissue engineering

International Nuclear Information System (INIS)

Verma, Devendra; Katti, Kalpana S.; Katti, Dinesh R.

2009-01-01

In the current work, polyelectrolyte complex (PEC) fibrous scaffolds for tissue engineering have been synthesized and a mechanism of their formation has been investigated. The scaffolds are synthesized using polygalacturonic acid and chitosan using the freeze drying methodology. Highly interconnected pores of sizes in the range of 5-20 μm are observed in the scaffolds. The thickness of the fibers was found to be in the range of 1-2 μm. Individual fibers have a nanogranular structure as observed using AFM imaging. In these scaffolds, PEC nanoparticles assemble together at the interface of ice crystals during freeze drying process. Further investigation shows that the freezing temperature and concentration have a remarkable effect on structure of scaffolds. Biocompatibility studies show that scaffold containing chitosan, polygalacturonic acid and hydroxyapatite promotes cell adhesion and proliferation. On the other hand, cells on scaffolds fabricated without hydroxyapatite nanoparticles showed poor adhesion.

Preparation of bioactive porous HA/PCL composite scaffolds

International Nuclear Information System (INIS)

Zhao, J.; Guo, L.Y.; Yang, X.B.; Weng, J.

2008-01-01

Porous hydroxyapatite (HA) bioceramic scaffold has been widely attracted the attention to act as a three-dimensional (3D) template for cell adhesion, proliferation, differentiation and thus promoting bone and cartilage regeneration because of its osteoinduction. However, the porous bioceramic scaffold is fragile so that it is not suitable to be applied in clinic for bone repair or replacement. Therefore, it is significant to improve the mechanical property of porous HA bioceramics while the interconnected structure is maintained for tissue ingrowth in vivo. In the present research, a porous composite scaffold composed of HA scaffold and polycaprolactone (PCL) lining was fabricated by the method of polymer impregnating to produce HA scaffold coated with PCL lining. Subsequently, the composite scaffolds were deposited with biomimetic coating for improving the bioactivity. The HA/PCL composite scaffolds with improved mechanical property and bioactivity is expected to be a promising bone substitute in tissue engineering applications

Evaluation of Posterolateral Lumbar Fusion in Sheep Using Mineral Scaffolds Seeded with Cultured Bone Marrow Cells

Directory of Open Access Journals (Sweden)

María D. Cuenca-López

2014-12-01

Full Text Available The objective of this study is to investigate the efficacy of hybrid constructs in comparison to bone grafts (autograft and allograft for posterolateral lumbar fusion (PLF in sheep, instrumented with transpedicular screws and bars. Hybrid constructs using cultured bone marrow (BM mesenchymal stem cells (MSCs have shown promising results in several bone healing models. In particular, hybrid constructs made by calcium phosphate-enriched cells have had similar fusion rates to bone autografts in posterolateral lumbar fusion in sheep. In our study, four experimental spinal fusions in two animal groups were compared in sheep: autograft and allograft (reference group, hydroxyapatite scaffold, and hydroxyapatite scaffold seeded with cultured and osteoinduced bone marrow MSCs (hybrid construct. During the last three days of culture, dexamethasone (dex and beta-glycerophosphate (β-GP were added to potentiate osteoinduction. The two experimental situations of each group were tested in the same spinal segment (L4–L5. Spinal fusion and bone formation were studied by clinical observation, X-ray, computed tomography (CT, histology, and histomorphometry. Lumbar fusion rates assessed by CT scan and histology were higher for autograft and allograft (70% than for mineral scaffold alone (22% and hybrid constructs (35%. The quantity of new bone formation was also higher for the reference group, quite similar in both (autograft and allograft. Although the hybrid scaffold group had a better fusion rate than the non-hybrid scaffold group, the histological analysis revealed no significant differences between them in terms of quantity of bone formation. The histology results suggested that mineral scaffolds were partly resorbed in an early phase, and included in callus tissues. Far from the callus area the hydroxyapatite alone did not generate bone around it, but the hybrid scaffold did. In nude mice, labeled cells were induced to differentiate in vivo and monitored

Extrusion-based, three-dimensional printing of calcium-phosphate scaffolds

Science.gov (United States)

Witek, Lukasz

Small or large bone defects, can occur due to a variety of reasons: congenital disorders, infections, tumors, or traumas which can lead to significant disabilities. There is an assortment of bone grafting procedures, each having their own respective advantages and disadvantages and exhibiting certain essential characteristics. Among the available grafts, autogenous (autograft), allograft, xenograft, and alloplasts, all exhibit a minimum of two-thirds of the essential characteristics and have been proven useful in fully or partially repairing skeletal defects. However, different host-to-grafting material responses have been reported and should be taken into consideration when determining treatment options. A large range of physical and chemical properties can be achieved with calcium phosphate based materials, which possess two of the ideal characteristics for grafting procedures: osteoconduction and osseointegration. Calcium phosphate based scaffolds composed of hydroxyapatite (HA), beta-tri-calcium phosphate (beta-TCP), or a combination of both (HA/beta-TCP) were investigated as materials for three-dimensional printing process to create layer-by-layer structures for use as bone regeneration scaffolds. Different calcium-phosphate phases will result in different degrees of in vivo dissolution and/or cell-mediated resorption. There has been a growing interest in BCP because it has been shown that this material improves the formation of new bone inside the implanted scaffold. The literature indicates that the faster dissolution rate of ?-TCP would be greatly responsible of this enhancement. However, in vitro tests indicate that fast dissolution can decrease the mechanical strength of BCP scaffolds. Furthermore, studies reported that HA has higher mechanical strength and lower degradation rate than beta-TCP. Therefore, the HA/beta-TCP ratio is a key parameter controlling the performance of the scaffold for bone repair applications, since it determines degradation rate

Geometrical versus Random β-TCP Scaffolds: Exploring the Effects on Schwann Cell Growth and Behavior.

Directory of Open Access Journals (Sweden)

Lauren Sweet

Full Text Available Numerous studies have demonstrated that Schwann cells (SCs play a role in nerve regeneration; however, their role in innervating a bioceramic scaffold for potential application in bone regeneration is still unknown. Here we report the cell growth and functional behavior of SCs on β-tricalcium phosphate (β-TCP scaffolds arranged in 3D printed-lattice (P-β-TCP and randomly-porous, template-casted (N-β-TCP structures. Our results indicate that SCs proliferated well and expressed the phenotypic markers p75LNGFR and the S100-β subunit of SCs as well as displayed growth morphology on both scaffolds, but SCs showed spindle-shaped morphology with a significant degree of SCs alignment on the P-β-TCP scaffolds, seen to a lesser degree in the N-β-TCP scaffold. The gene expressions of nerve growth factor (β-ngf, neutrophin-3 (nt-3, platelet-derived growth factor (pdgf-bb, and vascular endothelial growth factor (vegf-a were higher at day 7 than at day 14. While no significant differences in protein secretion were measured between these last two time points, the scaffolds promoted the protein secretion at day 3 compared to that on the cell culture plates. These results together imply that the β-TCP scaffolds can support SC cell growth and that the 3D-printed scaffold appeared to significantly promote the alignment of SCs along the struts. Further studies are needed to investigate the early and late stage relationship between gene expression and protein secretion of SCs on the scaffolds with refined characteristics, thus better exploring the potential of SCs to support vascularization and innervation in synthetic bone grafts.

Fabrication of uniaxially aligned 3D electrospun scaffolds for neural regeneration

Energy Technology Data Exchange (ETDEWEB)

Subramanian, Anuradha; Krishnan, Uma Maheswari; Sethuraman, Swaminathan, E-mail: swami@sastra.edu [Center for Nanotechnology and Advanced Biomaterials, SASTRA University, Thanjavur 613 401, Tamil Nadu (India)

2011-04-15

Nanofibrous scaffolds are very promising physical guidance substrates for regenerating nerves to traverse larger nerve gaps. In this study, we have attempted to develop 2D random and 3D longitudinally oriented nanofibers of poly(lactide-co-glycolide) (PLGA) by the modified electrospinning process and characterized the surface morphology, mechanical properties, porosity, degradation and wettability. The orientation of aligned fibers was optimized by varying the speed of the rotating mandrel in the electrospinning process. The mean diameter of random PLGA nanofibers was 197 {+-} 72 nm, whereas that of the aligned PLGA fiber was 187 {+-} 121 nm. The pore size of aligned PLGA nanofibers (3.5 {+-} 1.1 {mu}m) was significantly lower than their respective random nanofibers (8.0 {+-} 2.0 {mu}m) (p < 0.05). However, the percentage porosity of both scaffolds was comparable (p > 0.05). The mass loss percentage and molecular weight loss percentage due to degradation was higher in random PLGA fibers when compared to aligned PLGA after 5 weeks (p < 0.05). The tensile strength and Young's modulus of random PLGA fibers were significantly higher than those of the aligned PLGA nanofibers (p < 0.05). Both random and longitudinally aligned scaffolds were used for the in vitro culture of Schwann cells. Morphology and cell proliferation results demonstrated that the aligned fibers assist the direction of Schwann cells and a better proliferation rate than their random fibers. The results confirmed that aligned nanofibers have better deformability, slow degradation, comparable porosity and orientation cues than random nanofibers. Hence the longitudinally aligned nanofibers may be ideal scaffolds for nerve regeneration.

Exploring the link between maternal attachment-related anxiety and avoidance and mindful parenting: The mediating role of self-compassion.

Science.gov (United States)

Moreira, Helena; Carona, Carlos; Silva, Neuza; Nunes, Joana; Canavarro, Maria Cristina

2016-12-01

Mindful parenting has been described as a set of parental practices or skills that seek to enhance moment-to-moment awareness in the parent-child relationship. Although it has been suggested that adopting a mindful approach in parenting may foster positive parent-child relationships and promote the psychological functioning of children and parents, little is known about the factors that may be associated with this parental skill. In this study, we aimed to examine whether attachment-related anxiety and avoidance were associated with mindful parenting through self-compassion. The sample included 290 mothers of school-aged children and adolescents recruited in school settings, who completed self-reported measures of adult attachment (Experiences in Close Relationships - Relationships Structures), self-compassion (Self-compassion Scale), and mindful parenting (Interpersonal Mindfulness in Parenting Scale). Structural equation modelling was used to test the proposed mediation model and to ascertain direct and indirect effects among study variables. Whereas attachment avoidance had a direct effect on mindful parenting, attachment anxiety was indirectly associated with mindful parenting through self-compassion. Specifically, higher levels of anxiety were associated with lower self-compassion, which, in turn, was associated with lower levels of mindful parenting. Higher levels of avoidance were directly associated with lower levels of mindful parenting. These results demonstrate that mothers' attachment dimensions play an important role in their levels of mindful parenting, although through different pathways. Interventions aimed at promoting mindful parenting skills should attempt to promote parents' self-compassion and consider parents' levels of attachment insecurity. The results underline the important role of mothers' attachment on levels of mindful parenting and evidence different pathways through which attachment anxiety and attachment avoidance are associated with

Does Parental Mind-Mindedness Account for Cross-Cultural Differences in Preschoolers' Theory of Mind?

Science.gov (United States)

Hughes, Claire; Devine, Rory T; Wang, Zhenlin

2017-02-03

This study of 241 parent-child dyads from the United Kingdom (N = 120, M age  = 3.92, SD = 0.53) and Hong Kong (N = 121, M age  = 3.99, SD = 0.50) breaks new ground by adopting a cross-cultural approach to investigate children's theory of mind and parental mind-mindedness. Relative to the Hong Kong sample, U.K. children showed superior theory-of-mind performance and U.K. parents showed greater levels of mind-mindedness. Within both cultures parental mind-mindedness was correlated with theory of mind. Mind-mindedness also accounted for cultural differences in preschoolers' theory of mind. We argue that children's family environments might shed light on how culture shapes children's theory of mind. © 2017 The Authors. Child Development published by Wiley Periodicals, Inc. on behalf of Society for Research in Child Development.

Biomimetic nanoclay scaffolds for bone tissue engineering

Science.gov (United States)

Ambre, Avinash Harishchandra

Tissue engineering offers a significant potential alternative to conventional methods for rectifying tissue defects by evoking natural regeneration process via interactions between cells and 3D porous scaffolds. Imparting adequate mechanical properties to biodegradable scaffolds for bone tissue engineering is an important challenge and extends from molecular to macroscale. This work focuses on the use of sodium montmorillonite (Na-MMT) to design polymer composite scaffolds having enhanced mechanical properties along with multiple interdependent properties. Materials design beginning at the molecular level was used in which Na-MMT clay was modified with three different unnatural amino acids and further characterized using Fourier Transform Infrared (FTIR) spectroscopy, X-ray diffraction (XRD). Based on improved bicompatibility with human osteoblasts (bone cells) and intermediate increase in d-spacing of MMT clay (shown by XRD), 5-aminovaleric acid modified clay was further used to prepare biopolymer (chitosan-polygalacturonic acid complex) scaffolds. Osteoblast proliferation in biopolymer scaffolds containing 5-aminovaleric acid modified clay was similar to biopolymer scaffolds containing hydroxyapatite (HAP). A novel process based on biomineralization in bone was designed to prepare 5-aminovaleric acid modified clay capable of imparting multiple properties to the scaffolds. Bone-like apatite was mineralized in modified clay and a novel nanoclay-HAP hybrid (in situ HAPclay) was obtained. FTIR spectroscopy indicated a molecular level organic-inorganic association between the intercalated 5-aminovaleric acid and mineralized HAP. Osteoblasts formed clusters on biopolymer composite films prepared with different weight percent compositions of in situ HAPclay. Human MSCs formed mineralized nodules on composite films and mineralized extracellular matrix (ECM) in composite scaffolds without the use of osteogenic supplements. Polycaprolactone (PCL), a synthetic polymer, was

Mindfulness og mental sundhed

DEFF Research Database (Denmark)

Wistoft, Karen

2011-01-01

Mindfulness is a way to practice 'healthy mindedness' – a form of self help that has been the subject for research and development of a number of new significant self-technologies, therapy and meditation treatment methods. To be mindful can help people to feel more relaxed (serenity) and fully...... alive. The article aims at describing realistic expectations to the contribution of mindfulness to health education work in the field of mental health. The article discuss ways in which mindfulnesss is connected with established health education in the mental health promotion field, and ways in which...... mindfulness breaks with established health education. Interest in utilising mindfulness and mindfulness-inspired methods in health-education intervention has increased in recent years. Mindfulness is seen here as an answer to how to achieve more accepting presence, and thereby a healthier mental life...

In vitro chondrogenic differentiation of human adipose-derived stem cells with silk scaffolds

Directory of Open Access Journals (Sweden)

Hyeon Joo Kim

2012-12-01

Full Text Available Human adipose-derived stem cells have shown chondrogenic differentiation potential in cartilage tissue engineering in combination with natural and synthetic biomaterials. In the present study, we hypothesized that porous aqueous-derived silk protein scaffolds would be suitable for chondrogenic differentiation of human adipose-derived stem cells. Human adipose-derived stem cells were cultured up to 6 weeks, and cell proliferation and chondrogenic differentiation were investigated and compared with those in conventional micromass culture. Cell proliferation, glycosaminoglycan, and collagen levels in aqueous-derived silk scaffolds were significantly higher than in micromass culture. Transcript levels of SOX9 and type II collagen were also upregulated in the cell–silk constructs at 6 weeks. Histological examination revealed that the pores of the silk scaffolds were filled with cells uniformly distributed. In addition, chondrocyte-specific lacunae formation was evident and distributed in the both groups. The results suggest the biodegradable and biocompatible three-dimensional aqueous-derived silk scaffolds provided an improved environment for chondrogenic differentiation compared to micromass culture.

Mind over matter? I: philosophical aspects of the mind-brain problem.

Science.gov (United States)

Schimmel, P

2001-08-01

To conceptualize the essence of the mind-body or mind-brain problem as one of metaphysics rather than science, and to propose a formulation of the problem in the context of current scientific knowledge and its limitations. The background and conceptual parameters of the mind-body problem are delineated, and the limitations of brain research in formulating a solution identified. The problem is reformulated and stated in terms of two propositions. These constitute a 'double aspect theory'. The problem appears to arise as a consequence of the conceptual limitations of the human mind, and hence remains essentially a metaphysical one. A 'double aspect theory' recognizes the essential unity of mind and brain, while remaining consistent with the dualism inherent in human experience.

Mindfully Green and Healthy: An Indirect Path from Mindfulness to Ecological Behavior

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Sonja M. Geiger

2018-01-01

Full Text Available This paper examines the nature of the link between mindfulness and ecological behavior. Based on the notion that mindfulness incorporates heightened awareness of bodily sensations, we suggest an indirect path from mindfulness to ecological behavior that is mediated through individual health behavior, such as improved nutrition and increased exercise. This indirect path is corroborated with two online studies (n = 147/n = 239 where mindfulness, personal health behavior and ecological behavior were assessed. We conclude that increased mindful awareness of momentary experience indeed favors more healthy lifestyles, which in turn relate to increased ecological behavior beyond personal health benefits. The findings support an agreeableness of personal and planetary health behavior and open up a path for environmental educational interventions based on mindfulness practices and personal health gains.

Mindfulness and its relationship with eating disorders symptomatology in women receiving residential treatment.

Science.gov (United States)

Butryn, Meghan L; Juarascio, Adrienne; Shaw, Jena; Kerrigan, Stephanie G; Clark, Vicki; O'Planick, Antonia; Forman, Evan M

2013-01-01

Mindfulness and its related constructs (e.g., awareness and acceptance) are increasingly being recognized as relevant to understanding eating disorders and improving treatment. The purpose of this study was to (1) examine the relationship between mindfulness and ED symptomatology at baseline and (2) examine how changes in mindfulness relate to change in ED symptomatology. Measures of mindfulness and ED symptomatology were administered to 88 patients upon admission to residential ED treatment and at discharge. Baseline ED symptomatology was associated with lower awareness, acceptance, and cognitive defusion, and higher emotional avoidance. Improvements in these variables were related to improvement in ED symptomatology. Interventions targeting mindfulness could be beneficial for patients with EDs. Copyright © 2012 Elsevier Ltd. All rights reserved.

Anisotropic silk fibroin/gelatin scaffolds from unidirectional freezing

Energy Technology Data Exchange (ETDEWEB)

Asuncion, Maria Christine Tankeh, E-mail: christine.asuncion@u.nus.edu [National University of Singapore, Department of Biomedical Engineering (Singapore); Goh, James Cho-Hong [National University of Singapore, Department of Biomedical Engineering (Singapore); National University of Singapore, Department of Orthopedic Surgery (Singapore); Toh, Siew-Lok [National University of Singapore, Department of Biomedical Engineering (Singapore); National University of Singapore, Department of Mechanical Engineering (Singapore)

2016-10-01

Recent studies have underlined the importance of matching scaffold properties to the biological milieu. Tissue, and thus scaffold, anisotropy is one such property that is important yet sometimes overlooked. Methods that have been used to achieve anisotropic scaffolds present challenges such as complicated fabrication steps, harsh processing conditions and toxic chemicals involved. In this study, unidirectional freezing was employed to fabricate anisotropic silk fibroin/gelatin scaffolds in a simple and mild manner. Morphological, mechanical, chemical and cellular compatibility properties were investigated, as well as the effect of the addition of gelatin to certain properties of the scaffold. It was shown that scaffold properties were suitable for cell proliferation and that mesenchymal stem cells were able to align themselves along the directed fibers. The fabricated scaffolds present a platform that can be used for anisotropic tissue engineering applications such as cardiac patches. - Highlights: • Silk/gelatin scaffolds with unidirectional alignment were fabricated using a simple and scalable process • Presence of gelatin in silk resulted to lesser shrinkage, better water retention and improved cell proliferation. • Mesenchymal stem cells were shown to align themselves according to the fiber alignment.

Wetspun poly-L-(lactic acid)-borosilicate bioactive glass scaffolds for guided bone regeneration

Energy Technology Data Exchange (ETDEWEB)

Fernandes, João S., E-mail: joao.fernandes@dep.uminho.pt [3B' s Research Group - Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, AvePark-Parque de Ciência e Tecnologia, Zona Industrial da Gandra, 4805-017 Barco GMR (Portugal); ICVS/3B' s - PT Government Associate Laboratory, Braga/Guimarães (Portugal); Reis, Rui L. [3B' s Research Group - Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, AvePark-Parque de Ciência e Tecnologia, Zona Industrial da Gandra, 4805-017 Barco GMR (Portugal); ICVS/3B' s - PT Government Associate Laboratory, Braga/Guimarães (Portugal); Pires, Ricardo A., E-mail: rpires@dep.uminho.pt [3B' s Research Group - Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, AvePark-Parque de Ciência e Tecnologia, Zona Industrial da Gandra, 4805-017 Barco GMR (Portugal); ICVS/3B' s - PT Government Associate Laboratory, Braga/Guimarães (Portugal)

2017-02-01

We developed a porous poly-L-lactic acid (PLLA) scaffold compounded with borosilicate bioactive glasses (BBGs) endowing it with bioactive properties. Porous PLLA-BBG fibre mesh scaffolds were successfully prepared by the combination of wet spinning and fibre bonding techniques. Micro-computed tomography (μCT) confirmed that the PLLA-BBG scaffolds containing ≈ 25% of BBGs (w/w) exhibited randomly interconnected porous (58 to 62% of interconnectivity and 53 to 67% of porosity) with mean pore diameters higher that 100 μm. Bioactivity and degradation studies were performed by immersing the scaffolds in simulated body fluid (SBF) and ultrapure water, respectively. The PLLA-BBG scaffolds presented a faster degradation rate with a constant release of inorganic species, which are capable to produce calcium phosphate structures at the surface of the material after 7 days of immersion in SBF (Ca/P ratio of ~ 1.7). Cellular in vitro studies with human osteosarcoma cell line (Saos-2) and human adipose-derived stem cells (hASCs) showed that PLLA-BBGs are not cytotoxic to cells, while demonstrating their capacity to promote cell adhesion and proliferation. Overall, we showed that the proposed scaffolds present a tailored kinetics on the release of inorganic species and controlled biological response under conditions that mimic the bone physiological environment. - Highlights: • We prepared borosilicate glasses and their PLLA composites in the form of fibres. • These glasses imparted bioactivity and controlled degradability to the fibres. • The prepared fibres did not elicit cytotoxicity. • hASCs attached and proliferated in the surface and inner sections of the scaffolds. • The composites present appropriate properties to be used in bone tissue engineering.

Wetspun poly-L-(lactic acid)-borosilicate bioactive glass scaffolds for guided bone regeneration

International Nuclear Information System (INIS)

Fernandes, João S.; Reis, Rui L.; Pires, Ricardo A.

2017-01-01

We developed a porous poly-L-lactic acid (PLLA) scaffold compounded with borosilicate bioactive glasses (BBGs) endowing it with bioactive properties. Porous PLLA-BBG fibre mesh scaffolds were successfully prepared by the combination of wet spinning and fibre bonding techniques. Micro-computed tomography (μCT) confirmed that the PLLA-BBG scaffolds containing ≈ 25% of BBGs (w/w) exhibited randomly interconnected porous (58 to 62% of interconnectivity and 53 to 67% of porosity) with mean pore diameters higher that 100 μm. Bioactivity and degradation studies were performed by immersing the scaffolds in simulated body fluid (SBF) and ultrapure water, respectively. The PLLA-BBG scaffolds presented a faster degradation rate with a constant release of inorganic species, which are capable to produce calcium phosphate structures at the surface of the material after 7 days of immersion in SBF (Ca/P ratio of ~ 1.7). Cellular in vitro studies with human osteosarcoma cell line (Saos-2) and human adipose-derived stem cells (hASCs) showed that PLLA-BBGs are not cytotoxic to cells, while demonstrating their capacity to promote cell adhesion and proliferation. Overall, we showed that the proposed scaffolds present a tailored kinetics on the release of inorganic species and controlled biological response under conditions that mimic the bone physiological environment. - Highlights: • We prepared borosilicate glasses and their PLLA composites in the form of fibres. • These glasses imparted bioactivity and controlled degradability to the fibres. • The prepared fibres did not elicit cytotoxicity. • hASCs attached and proliferated in the surface and inner sections of the scaffolds. • The composites present appropriate properties to be used in bone tissue engineering.

Finite-element design and optimization of a three-dimensional tetrahedral porous titanium scaffold for the reconstruction of mandibular defects.

Science.gov (United States)

Luo, Danmei; Rong, Qiguo; Chen, Quan

2017-09-01

Reconstruction of segmental defects in the mandible remains a challenge for maxillofacial surgery. The use of porous scaffolds is a potential method for repairing these defects. Now, additive manufacturing techniques provide a solution for the fabrication of porous scaffolds with specific geometrical shapes and complex structures. The goal of this study was to design and optimize a three-dimensional tetrahedral titanium scaffold for the reconstruction of mandibular defects. With a fixed strut diameter of 0.45mm and a mean cell size of 2.2mm, a tetrahedral structural porous scaffold was designed for a simulated anatomical defect derived from computed tomography (CT) data of a human mandible. An optimization method based on the concept of uniform stress was performed on the initial scaffold to realize a minimal-weight design. Geometric and mechanical comparisons between the initial and optimized scaffold show that the optimized scaffold exhibits a larger porosity, 81.90%, as well as a more homogeneous stress distribution. These results demonstrate that tetrahedral structural titanium scaffolds are feasible structures for repairing mandibular defects, and that the proposed optimization scheme has the ability to produce superior scaffolds for mandibular reconstruction with better stability, higher porosity, and less weight. Copyright © 2017 IPEM. Published by Elsevier Ltd. All rights reserved.

Physicochemical properties and enhanced cellullar responses of biocompatible polymeric scaffolds treated with atmospheric pressure plasma using O{sub 2} gas

Energy Technology Data Exchange (ETDEWEB)

Lee, Hyun-Uk; Park, So-Young; Kang, Yoon-Hee [Department of Nano Fusion Technology, Pusan National University, Busan 609735 (Korea, Republic of); Jeong, Se-Young [Division of Cogni-mechatronics Engineering, Pusan National University, Miryang 627706 (Korea, Republic of); Choi, Sae-Hae; Jahng, Yoon-Young; Chung, Gook-Hyun [Division of Biological Sciences, Chonbuk National University, Jeonju 561756 (Korea, Republic of); Kim, Moon-Bum [Department of Dermatology, School of Medicine, Pusan National University, Busan (Korea, Republic of); Cho, Chae-Ryong, E-mail: crcho@pusan.ac.kr [Department of Nano Fusion Technology, Pusan National University, Busan 609735 (Korea, Republic of)

2011-04-08

Biocompatible polymeric scaffolds were fabricated by mixing 5 wt.% poly({epsilon}-caprolactone) (P) with 4 wt.% gelatin (G) and 1.6 wt.% Dulbecco's modified Eagle's medium containing 10% fetal bovine serum (D). These PGD scaffolds were also treated with atmospheric pressure (AP) plasma using O{sub 2} reactive gas (to create O-PGD scaffolds). The physicochemical and mechanical properties of the PGD scaffolds were characterized by in vitro biodegradability tests, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, contact angle measurements, and tensile strength measurements. The wettability and hydrophilic properties of the scaffold surface were improved remarkably by adding G and D to P, and by subsequent oxygen-assisted AP plasma treatment. An MTT assay, a cell attachment efficiency assay, scanning electron microscopy, and confocal microscopy revealed that Chinese Hamster Ovary (CHO)-K1 cells exhibited higher cell attachment and viability on the PGD and O-PGD scaffolds than on the P and PG scaffolds. Furthermore, the long-term viability of the CHO cells on the PGD and O-PGD scaffolds without exchanging the cell culture media was significantly improved compared to their viability on the P and PG scaffolds. Overall, the PGD and O-PGD scaffolds are expected to be useful as cell growth supporting biomaterials in tissue engineering.

The effect of 3D nanofibrous scaffolds on the chondrogenesis of induced pluripotent stem cells and their application in restoration of cartilage defects.

Science.gov (United States)

Liu, Ji; Nie, Huarong; Xu, Zhengliang; Niu, Xin; Guo, Shangchun; Yin, Junhui; Guo, Fei; Li, Gang; Wang, Yang; Zhang, Changqing

2014-01-01

The discovery of induced pluripotent stem cells (iPSCs) rendered the reprogramming of terminally differentiated cells to primary stem cells with pluripotency possible and provided potential for the regeneration and restoration of cartilage defect. Chondrogenic differentiation of iPSCs is crucial for their application in cartilage tissue engineering. In this study we investigated the effect of 3D nanofibrous scaffolds on the chondrogenesis of iPSCs and articular cartilage defect restoration. Super-hydrophilic and durable mechanic polycaprolactone (PCL)/gelatin scaffolds were fabricated using two separate electrospinning processes. The morphological structure and mechanical properties of the scaffolds were characterized. The chondrogenesis of the iPSCs in vitro and the restoration of the cartilage defect was investigated using scanning electron microscopy (SEM), the Cell Counting Kit-8 (CCK-8), histological observation, RT-qPCR, and western blot analysis. iPSCs on the scaffolds expressed higher levels of chondrogenic markers than the control group. In an animal model, cartilage defects implanted with the scaffold-cell complex exhibited an enhanced gross appearance and histological improvements, higher cartilage-specific gene expression and protein levels, as well as subchondral bone regeneration. Therefore, we showed scaffolds with a 3D nanofibrous structure enhanced the chondrogenesis of iPSCs and that iPSC-containing scaffolds improved the restoration of cartilage defects to a greater degree than did scaffolds alone in vivo.

The effect of 3D nanofibrous scaffolds on the chondrogenesis of induced pluripotent stem cells and their application in restoration of cartilage defects.

Directory of Open Access Journals (Sweden)

Ji Liu

Full Text Available The discovery of induced pluripotent stem cells (iPSCs rendered the reprogramming of terminally differentiated cells to primary stem cells with pluripotency possible and provided potential for the regeneration and restoration of cartilage defect. Chondrogenic differentiation of iPSCs is crucial for their application in cartilage tissue engineering. In this study we investigated the effect of 3D nanofibrous scaffolds on the chondrogenesis of iPSCs and articular cartilage defect restoration. Super-hydrophilic and durable mechanic polycaprolactone (PCL/gelatin scaffolds were fabricated using two separate electrospinning processes. The morphological structure and mechanical properties of the scaffolds were characterized. The chondrogenesis of the iPSCs in vitro and the restoration of the cartilage defect was investigated using scanning electron microscopy (SEM, the Cell Counting Kit-8 (CCK-8, histological observation, RT-qPCR, and western blot analysis. iPSCs on the scaffolds expressed higher levels of chondrogenic markers than the control group. In an animal model, cartilage defects implanted with the scaffold-cell complex exhibited an enhanced gross appearance and histological improvements, higher cartilage-specific gene expression and protein levels, as well as subchondral bone regeneration. Therefore, we showed scaffolds with a 3D nanofibrous structure enhanced the chondrogenesis of iPSCs and that iPSC-containing scaffolds improved the restoration of cartilage defects to a greater degree than did scaffolds alone in vivo.

Human Mind Maps

Science.gov (United States)

Glass, Tom

2016-01-01

When students generate mind maps, or concept maps, the maps are usually on paper, computer screens, or a blackboard. Human Mind Maps require few resources and little preparation. The main requirements are space where students can move around and a little creativity and imagination. Mind maps can be used for a variety of purposes, and Human Mind…

Comparison of the components of mindfulness on Stimulant and opiate addicts

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Sayeadyounes Mohammadi

2016-07-01

Full Text Available Background: Phenomenon of addiction as one of the social problem have the high prevalence, especially among youth. Study and scientific cognition of mental and psychological components of addicts is very important in order to help them to compatibility and reduce their psychological problem. Therefore, the aim of present study was to comparison of mindfulness components on stimulant and opiate addicts. Materials & Methods: In this study 60 addicts (30 opiate addicts and 30 stimulants addicts were studied by using Five Factor Mindfulness Questionnaire (FFMQ. Data were analyzed by using multivariate analysis of variance (MANOVA. Results: findings showed that there was a significant difference between opiate and stimulant addicts in mindfulness components. Conclusion: results illustrated that the opiate addicts gained higher scores than stimulant addicts in mindfulness components. The results also emphasized that mindfulness components are as determinant variable in opiate and stimulant addicts pathology.

Psychometric Evaluation of Chinese-Language 44-Item and 10-Item Big Five Personality Inventories, Including Correlations with Chronotype, Mindfulness and Mind Wandering.

Science.gov (United States)

Carciofo, Richard; Yang, Jiaoyan; Song, Nan; Du, Feng; Zhang, Kan

2016-01-01

The 44-item and 10-item Big Five Inventory (BFI) personality scales are widely used, but there is a lack of psychometric data for Chinese versions. Eight surveys (total N = 2,496, aged 18-82), assessed a Chinese-language BFI-44 and/or an independently translated Chinese-language BFI-10. Most BFI-44 items loaded strongly or predominantly on the expected dimension, and values of Cronbach's alpha ranged .698-.807. Test-retest coefficients ranged .694-.770 (BFI-44), and .515-.873 (BFI-10). The BFI-44 and BFI-10 showed good convergent and discriminant correlations, and expected associations with gender (females higher for agreeableness and neuroticism), and age (older age associated with more conscientiousness and agreeableness, and also less neuroticism and openness). Additionally, predicted correlations were found with chronotype (morningness positive with conscientiousness), mindfulness (negative with neuroticism, positive with conscientiousness), and mind wandering/daydreaming frequency (negative with conscientiousness, positive with neuroticism). Exploratory analysis found that the Self-discipline facet of conscientiousness positively correlated with morningness and mindfulness, and negatively correlated with mind wandering/daydreaming frequency. Furthermore, Self-discipline was found to be a mediator in the relationships between chronotype and mindfulness, and chronotype and mind wandering/daydreaming frequency. Overall, the results support the utility of the BFI-44 and BFI-10 for Chinese-language big five personality research.

Addition of selenium nanoparticles to electrospun silk scaffolds improves mammalian cell activity while reducing bacterial growth

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Stanley Chung

2016-07-01

Full Text Available Silk possesses many beneficial wound healing properties, and electrospun scaffolds are especially applicable for skin applications, due to their smaller interstices and higher surface areas compared to non-electrospun equivalents. However, purified silk promotes microbial growth. In contrast, selenium nanoparticles have excellent antibacterial properties and are a novel antimicrobial chemistry. Here, electrospun silk scaffolds were doped with selenium nanoparticles to impart antibacterial properties to the silk scaffolds. Results showed significantly improved bacterial inhibition and improvement in human dermal fibroblast metabolic activity. These results suggest that the addition of selenium nanoparticles to electrospun silk is a promising approach to improve wound healing with reduced infection, without relying on antibiotics.

Surface modified electrospun nanofibrous scaffolds for nerve tissue engineering

International Nuclear Information System (INIS)

Prabhakaran, Molamma P; Venugopal, J; Chan, Casey K; Ramakrishna, S

2008-01-01

The development of biodegradable polymeric scaffolds with surface properties that dominate interactions between the material and biological environment is of great interest in biomedical applications. In this regard, poly-ε-caprolactone (PCL) nanofibrous scaffolds were fabricated by an electrospinning process and surface modified by a simple plasma treatment process for enhancing the Schwann cell adhesion, proliferation and interactions with nanofibers necessary for nerve tissue formation. The hydrophilicity of surface modified PCL nanofibrous scaffolds (p-PCL) was evaluated by contact angle and x-ray photoelectron spectroscopy studies. Naturally derived polymers such as collagen are frequently used for the fabrication of biocomposite PCL/collagen scaffolds, though the feasibility of procuring large amounts of natural materials for clinical applications remains a concern, along with their cost and mechanical stability. The proliferation of Schwann cells on p-PCL nanofibrous scaffolds showed a 17% increase in cell proliferation compared to those on PCL/collagen nanofibrous scaffolds after 8 days of cell culture. Schwann cells were found to attach and proliferate on surface modified PCL nanofibrous scaffolds expressing bipolar elongations, retaining their normal morphology. The results of our study showed that plasma treated PCL nanofibrous scaffolds are a cost-effective material compared to PCL/collagen scaffolds, and can potentially serve as an ideal tissue engineered scaffold, especially for peripheral nerve regeneration.

Dispositional mindfulness and the wandering mind: Implications for attentional control in older adults.

Science.gov (United States)

Fountain-Zaragoza, Stephanie; Londerée, Allison; Whitmoyer, Patrick; Prakash, Ruchika Shaurya

2016-08-01

Age-related cognitive decline brings decreases in functional status. Dispositional mindfulness, the tendency towards present-moment attention, is hypothesized to correspond with enhanced attention, whereas mind-wandering may be detrimental to cognition. The relationships among mindfulness, task-related and task-unrelated thought, and attentional control performance on Go/No-Go and Continuous Performance tasks were examined in older adults. Dispositional mindfulness was negatively associated with task-unrelated thought and was positively associated with reactive control, but not proactive control or Go/No-Go performance. Although mind-wandering was not directly associated with performance, task-unrelated thought mediated the mindfulness-proactive control relation. Fewer task-unrelated thoughts were associated with lower proactive control. Interestingly, this effect was moderated by working memory such that it was present for those with low-average, but not high, working memory. This study highlights the importance of dispositional mindfulness and mind-wandering propensity in accounting for individual differences in attentional control in older adults, providing important targets for future cognitive remediation interventions. Copyright © 2016 Elsevier Inc. All rights reserved.

A mind you can count on: validating breath counting as a behavioral measure of mindfulness

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Daniel B Levinson

2014-10-01

Full Text Available Mindfulness practice of present moment awareness promises many benefits, but has eluded rigorous behavioral measurement. To date, research has relied on self-reported mindfulness or heterogeneous mindfulness trainings to infer skillful mindfulness practice and its effects. In four independent studies with over 400 total participants, we present the first construct validation of a behavioral measure of mindfulness, breath counting. We found it was reliable, correlated with self-reported mindfulness, differentiated long-term meditators from age-matched controls, and was distinct from sustained attention and working memory measures. In addition, we employed breath counting to test the nomological network of mindfulness. As theorized, we found skill in breath counting associated with more meta-awareness, less mind wandering, better mood, and greater nonattachment (i.e. less attentional capture by distractors formerly paired with reward. We also found in a randomized online training study that 4 weeks of breath counting training improved mindfulness and decreased mind wandering relative to working memory training and no training controls. Together, these findings provide the first evidence for breath counting as a behavioral measure of mindfulness.

A 3D model of ovarian cancer cell lines on peptide nanofiber scaffold to explore the cell–scaffold interaction and chemotherapeutic resistance of anticancer drugs

Directory of Open Access Journals (Sweden)

Zehong Yang

2011-02-01

Full Text Available Zehong Yang1, Xiaojun Zhao1,21Nanomedicine Laboratory, West China Hospital and Institute for Nanobiomedical Technology and Membrane Biology, Sichuan University, Chengdu, People’s Republic of China; 2Center for Biomedical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USAAbstract: RADA16-I peptide hydrogel, a type of nanofiber scaffold derived from self-assembling peptide RADA16-I, has been extensively applied to regenerative medicine and tissue repair in order to develop novel nanomedicine systems. In this study, using RADA16-I peptide hydrogel, a three-dimensional (3D cell culture model was fabricated for in vitro culture of three ovarian cancer cell lines. Firstly, the peptide nanofiber scaffold was evaluated by transmission electron microscopy and atom force microscopy. Using phase contrast microscopy, the appearance of the representative ovarian cancer cells encapsulated in RADA16-I peptide hydrogel on days 1, 3, and 7 in 24-well Petri dishes was illustrated. The cancer cell–nanofiber scaffold construct was cultured for 5 days, and the ovarian cancer cells had actively proliferative potential. The precultured ovarian cancer cells exhibited nearly similar adhesion properties and invasion potentials in vitro between RADA16-I peptide nanofiber and type I collagen, which suggested that RADA16-I peptide hydrogel had some similar characteristics to type I collagen. The precultured ovarian cancer cells had two-fold to five-fold higher anticancer drug resistance than the conventional two-dimensional Petri dish culture. So the 3D cell model on peptide nanofiber scaffold is an optimal type of cell pattern for anticancer drug screening and tumor biology.Keywords: 3D culture, anticancer drug, nanofiber scaffold, cell viability, ovarian cancer

The prevalence of mind-body dualism in early China.

Science.gov (United States)

Slingerland, Edward; Chudek, Maciej

2011-07-01

We present the first large-scale, quantitative examination of mind and body concepts in a set of historical sources by measuring the predictions of folk mind-body dualism against the surviving textual corpus of pre-Qin (pre-221 BCE) China. Our textual analysis found clear patterns in the historically evolving reference of the word xin (heart/heart-mind): It alone of the organs was regularly contrasted with the physical body, and during the Warring States period it became less associated with emotions and increasingly portrayed as the unique locus of "higher" cognitive abilities. We interpret this as a semantic shift toward a shared cognitive bias in response to a vast and rapid expansion of literacy. Our study helps test the proposed universality of folk dualism, adds a new quantitative approach to the methods used in the humanities, and opens up a new and valuable data source for cognitive scientists: the record of dead minds. Copyright © 2011 Cognitive Science Society, Inc.

Representing metarepresentations: is there theory of mind-specific cognition?

Science.gov (United States)

Egeth, Marc; Kurzban, Robert

2009-03-01

What cognitive mechanisms underlie Theory of Mind? Some infer domain-specific Theory of Mind cognition based the pattern of children diagnosed with autism failing the False Belief test but passing the False Photograph test. However, we argue that the False Belief test entails various task demands the False Photograph task does not, including the necessity to represent a higher-order representation (a metarepresentation), thus confounding the inference of domain-specificity. Instead, a general difficulty that affects representations of metarepresentations might account for the seeming domain-specific failure. Here we find that False-Belief failing False-Photograph passing children fail the Meta Photograph test, a new photograph-domain test that requires subjects to represent a metarepresentation. We conclude that people who fail the False Belief test but pass the False Photograph test do not necessarily have a content-specific Theory of Mind deficit. Instead, the general ability to represent representations and metarepresentations might underlie Theory of Mind.

In vitro degradation and mechanical properties of PLA-PCL copolymer unit cell scaffolds generated by two-photon polymerization

International Nuclear Information System (INIS)

Felfel, R M; Gimeno-Fabra, Miquel; Ahmed, Ifty; Scotchford, Colin; Grant, David M; Poocza, Leander; Milde, Tobias; Hildebrand, Gerhard; Liefeith, Klaus; Sottile, Virginie

2016-01-01

The manufacture of 3D scaffolds with specific controlled porous architecture, defined microstructure and an adjustable degradation profile was achieved using two-photon polymerization (TPP) with a size of 2  ×  4  ×  2 mm 3 . Scaffolds made from poly(D,L-lactide-co-ε-caprolactone) copolymer with varying lactic acid (LA) and ε -caprolactone (CL) ratios (LC16:4, 18:2 and 9:1) were generated via ring-opening-polymerization and photoactivation. The reactivity was quantified using photo-DSC, yielding a double bond conversion ranging from 70% to 90%. The pore sizes for all LC scaffolds were see 300 μm and throat sizes varied from 152 to 177 μm. In vitro degradation was conducted at different temperatures; 37, 50 and 65 °C. Change in compressive properties immersed at 37 °C over time was also measured. Variations in thermal, degradation and mechanical properties of the LC scaffolds were related to the LA/CL ratio. Scaffold LC16:4 showed significantly lower glass transition temperature (T g ) (4.8 °C) in comparison with the LC 18:2 and 9:1 (see 32 °C). Rates of mass loss for the LC16:4 scaffolds at all temperatures were significantly lower than that for LC18:2 and 9:1. The degradation activation energies for scaffold materials ranged from 82.7 to 94.9 kJ mol −1 . A prediction for degradation time was applied through a correlation between long-term degradation studies at 37 °C and short-term studies at elevated temperatures (50 and 65 °C) using the half-life of mass loss (Time (M 1/2 )) parameter. However, the initial compressive moduli for LC18:2 and 9:1 scaffolds were 7 to 14 times higher than LC16:4 (see 0.27) which was suggested to be due to its higher CL content (20%). All scaffolds showed a gradual loss in their compressive strength and modulus over time as a result of progressive mass loss over time. The manufacturing process utilized and the scaffolds produced have potential for use in tissue engineering and regenerative medicine

Design of a bioresorbable polymeric scaffold for osteoblast culture

Science.gov (United States)

Ditaranto, Vincent M., Jr.

Bioresorbable polymeric scaffolds were designed for the purpose of growing rat osteosarcoma cells (ROS 17/2.8) using the compression molding method. The material used in the construction of the scaffolds was a mixture of polycaprolactone (PCL), Hydroxyapatite (HA), Glycerin (GL) and salt (NaCl) for porosity. The concentration of the several materials utilized, was determined by volume. Past research at the University of Massachusetts Lowell (UML) has successfully utilized the compression molding method for the construction of scaffolds, but was unable to accomplish the goal of long term cell survival and complete cellular proliferation throughout a three dimensional scaffold. This research investigated various concentrations of the materials and molding temperatures used for the manufacture of scaffolds in order to improve the scaffold design and address those issues. The design of the scaffold using the compression molding process is detailed in the Method and Materials section of this thesis. The porogen (salt) used for porosity was suspected as a possible source of contamination causing cell apoptosis in past studies. This research addressed the issues for cell survival and proliferation throughout a three dimensional scaffold. The leaching of the salt was one major design modification. This research successfully used ultrasonic leaching in addition to the passive method. Prior to cell culture, the scaffolds were irradiated to 2.75 Mrad, with cobalt-60 gamma radionuclide. The tissue culture consisted of two trials: (1) cell culture in scaffolds cleaned with passive leaching; (2) cell culture with scaffolds cleaned with ultrasonic leaching. Cell survival and proliferation was accomplished only with the addition of ultrasonic leaching of the scaffolds. Analysis of the scaffolds included Scanning Electron Microscopy (SEM), Nikon light microscopy and x-ray mapping of the calcium, sodium and chloride ion distribution. The cells were analyzed by Environmental Scanning

Multilayer porous UHMWPE scaffolds for bone defects replacement

International Nuclear Information System (INIS)

Maksimkin, A.V.; Senatov, F.S.; Anisimova, N.Yu.; Kiselevskiy, M.V.; Zalepugin, D.Yu.; Chernyshova, I.V.; Tilkunova, N.A.; Kaloshkin, S.D.

2017-01-01

Reconstruction of the structural integrity of the damaged bone tissue is an urgent problem. UHMWPE may be potentially used for the manufacture of porous implants simulating as closely as possible the porous cancellous bone tissue. But the extremely high molecular weight of the polymer does not allow using traditional methods of foaming. Porous and multilayer UHMWPE scaffolds with nonporous bulk layer and porous layer that mimics cancellous bone architecture were obtained by solid-state mixing, thermopressing and washing in subcritical water. Structural and mechanical properties of the samples were studied. Porous UHMWPE samples were also studied in vitro and in vivo. The pores of UHMWPE scaffold are open and interconnected. Volume porosity of the obtained samples was 79 ± 2%; the pore size range was 80–700 μm. Strong connection of the two layers in multilayer UHMWPE scaffolds was observed with decreased number of fusion defects. Functionality of implants based on multilayer UHMWPE scaffolds is provided by the fixation of scaffolds in the bone defect through ingrowths of the connective tissue into the pores, which ensures the maintenance of the animals' mobility - Highlights: • Porous UHMWPE scaffold mimics cancellous bone architecture, maintaining its flexibility. • Multilayer UHMWPE scaffold is able to simulate different types of bone tissue. • Fixation of scaffolds in the bone provides through ingrowths of the connective tissue into pores. • Multilayer UHMWPE scaffolds can be used for the formation of bone implants.

Multilayer porous UHMWPE scaffolds for bone defects replacement

Energy Technology Data Exchange (ETDEWEB)

Maksimkin, A.V. [National University of Science and Technology “MISIS”, Moscow (Russian Federation); Senatov, F.S., E-mail: senatov@misis.ru [National University of Science and Technology “MISIS”, Moscow (Russian Federation); Anisimova, N.Yu.; Kiselevskiy, M.V. [National University of Science and Technology “MISIS”, Moscow (Russian Federation); N.N. Blokhin Russian Cancer Research Center, Moscow (Russian Federation); Zalepugin, D.Yu.; Chernyshova, I.V.; Tilkunova, N.A. [State Plant of Medicinal Drugs, Moscow (Russian Federation); Kaloshkin, S.D. [National University of Science and Technology “MISIS”, Moscow (Russian Federation)

2017-04-01

Reconstruction of the structural integrity of the damaged bone tissue is an urgent problem. UHMWPE may be potentially used for the manufacture of porous implants simulating as closely as possible the porous cancellous bone tissue. But the extremely high molecular weight of the polymer does not allow using traditional methods of foaming. Porous and multilayer UHMWPE scaffolds with nonporous bulk layer and porous layer that mimics cancellous bone architecture were obtained by solid-state mixing, thermopressing and washing in subcritical water. Structural and mechanical properties of the samples were studied. Porous UHMWPE samples were also studied in vitro and in vivo. The pores of UHMWPE scaffold are open and interconnected. Volume porosity of the obtained samples was 79 ± 2%; the pore size range was 80–700 μm. Strong connection of the two layers in multilayer UHMWPE scaffolds was observed with decreased number of fusion defects. Functionality of implants based on multilayer UHMWPE scaffolds is provided by the fixation of scaffolds in the bone defect through ingrowths of the connective tissue into the pores, which ensures the maintenance of the animals' mobility - Highlights: • Porous UHMWPE scaffold mimics cancellous bone architecture, maintaining its flexibility. • Multilayer UHMWPE scaffold is able to simulate different types of bone tissue. • Fixation of scaffolds in the bone provides through ingrowths of the connective tissue into pores. • Multilayer UHMWPE scaffolds can be used for the formation of bone implants.

Highly charged cyanine fluorophores for trafficking scaffold degradation

International Nuclear Information System (INIS)

Owens, Eric A; Alyabyev, Sergey; Henary, Maged; Hyun, Hoon; Kim, Soon Hee; Lee, Jeong Heon; Park, GwangLi; Ashitate, Yoshitomo; Choi, Jungmun; Hong, Gloria H; Choi, Hak Soo; Lee, Sang Jin; Khang, Gilson

2013-01-01

Biodegradable scaffolds have been extensively used in the field of tissue engineering and regenerative medicine. However, noninvasive monitoring of in vivo scaffold degradation is still lacking. In order to develop a real-time trafficking technique, a series of meso-brominated near-infrared (NIR) fluorophores were synthesized and conjugated to biodegradable gelatin scaffolds. Since the pentamethine cyanine core is highly lipophilic, the side chain of each fluorophore was modified with either quaternary ammonium salts or sulfonate groups. The physicochemical properties such as lipophilicity and net charge of fluorophores played a key role in the fate of NIR-conjugated scaffolds in vivo after biodegradation. The positively charged fluorophore-conjugated scaffold fragments were found in salivary glands, lymph nodes, and most of the hepatobiliary excretion route. However, halogenated fluorophores intensively accumulated into lymph nodes and the liver. Interestingly, balanced-charged gelatin scaffolds were degraded into urine in a short period of time. These results demonstrate that the noninvasive optical imaging using NIR fluorophores can be useful for the translation of biodegradable scaffolds into the clinic. (paper)

Comparison of Engineered Peptide-Glycosaminoglycan Microfibrous Hybrid Scaffolds for Potential Applications in Cartilage Tissue Regeneration

Directory of Open Access Journals (Sweden)

Steven M. Romanelli

2015-07-01

Full Text Available Advances in tissue engineering have enabled the ability to design and fabricate biomaterials at the nanoscale that can actively mimic the natural cellular environment of host tissue. Of all tissues, cartilage remains difficult to regenerate due to its avascular nature. Herein we have developed two new hybrid polypeptide-glycosaminoglycan microfibrous scaffold constructs and compared their abilities to stimulate cell adhesion, proliferation, sulfated proteoglycan synthesis and soluble collagen synthesis when seeded with chondrocytes. Both constructs were designed utilizing self-assembled Fmoc-protected valyl cetylamide nanofibrous templates. The peptide components of the constructs were varied. For Construct I a short segment of dentin sialophosphoprotein followed by Type I collagen were attached to the templates using the layer-by-layer approach. For Construct II, a short peptide segment derived from the integrin subunit of Type II collagen binding protein expressed by chondrocytes was attached to the templates followed by Type II collagen. To both constructs, we then attached the natural polymer N-acetyl glucosamine, chitosan. Subsequently, the glycosaminoglycan chondroitin sulfate was then attached as the final layer. The scaffolds were characterized by Fourier transform infrared spectroscopy (FT-IR, differential scanning calorimetry (DSC, atomic force microscopy and scanning electron microscopy. In vitro culture studies were carried out in the presence of chondrocyte cells for both scaffolds and growth morphology was determined through optical microscopy and scanning electron microscopy taken at different magnifications at various days of culture. Cell proliferation studies indicated that while both constructs were biocompatible and supported the growth and adhesion of chondrocytes, Construct II stimulated cell adhesion at higher rates and resulted in the formation of three dimensional cell-scaffold matrices within 24 h. Proteoglycan

Mindfulness - en implicit utopi?

DEFF Research Database (Denmark)

Nielsen, Anne Maj

2014-01-01

The field of mindfulness and meditation has met growing interest in the western world during the last decades. Mindfulness aims to develop a friendly, accepting and mindful awareness in the present moment. Critiques have argued that this aim is deployed in a new kind of management technology where...... mindfulness is used for individualized stress-reduction in order to keep up with existing or worsened working conditions instead of stress-reducing changes in the common working conditions. Mindfulness research emphasizes positive outcomes in coping with demands and challenges in everyday life especially...... considering suffering (for example stress and pain). While explicit constructions of Utopia present ideas of specific societal communities in well-functioning harmony, the interest in mindfulness can in contradistinction be considered an implicit critique of present life-conditions and an “implicit utopia...

Exploring personality traits, mindfulness and sense of coherence of women working in higher education

Directory of Open Access Journals (Sweden)

Claude-Hélène Mayer

2016-07-01

Full Text Available Orientation: Previous research shows that personality traits (PT, mindfulness (MI and sense of coherence (SOC are connected to psychological well-being and of importance to Human Resource Management (HRM. Purpose: The purpose of this article was to determine the relationship between PT, MI and SOC of women working in South African Higher Education Institutions (HEIs. Motivation for study: The study explores the relationships of PT, MI and SOC in women in HEIs to contribute to a deeper understanding of these relationships within the HRM context, particularly with regard to training and development in HEIs. Research design, approach and method: A cross-sectional, survey-based research design was used to address the research objective. Both snowball and convenience sampling were utilised to obtain the sample (n = 125. The sample was derived from the Higher Education Resource Services network. The Life Orientation Questionnaire, Freiburger MI Inventory and Big Five PT Questionnaire were utilised and showed acceptable levels of reliability. Exploratory factor analysis with either a direct oblimin or varimax rotation was used to investigate the factor structure of the questionnaires (λ < 1 were used, because one of the questionnaires had not been used in the South African context before. Descriptive statistics, factor analysis, Spearman/ Pearson correlations, canonical correlations and multiple regressions were used to determine the relationship between the variables. Main findings: The results showed a significant relationship between the components PT, MI and SOC. It appears that PT plays a significant role in influencing MI and SOC. Practical/managerial implications: Managers and human resource practitioners need to recognise how PT, MI and SOC interrelate and need to become aware of the impact of these positive psychological constructs on women in HEIs. Contribution: These findings contribute new knowledge that can be used to create healthy HEIs

When Did Coloring Books Become Mindful? Exploring the Effectiveness of a Novel Method of Mindfulness-Guided Instructions for Coloring Books to Increase Mindfulness and Decrease Anxiety.

Science.gov (United States)

Mantzios, Michail; Giannou, Kyriaki

2018-01-01

Mindfulness has been associated with the use of coloring books for adults; however, the question of whether they do increase mindfulness has not been addressed. In two studies, we attempted to identify whether mindfulness is increased, and whether there is a need for ongoing guidance while coloring, similar to mindfulness meditation. In the first randomized controlled experiment, university students ( n = 88) were assigned to an unguided mandala coloring group (i.e., described in mainstream literature as a mindfulness practice) or to a free-drawing group. Measurements of state mindfulness and state anxiety were taken pre- and post- experiment. Results indicated no change in mindfulness or anxiety. In the second randomized controlled experiment, university students ( n = 72) were assigned to an unguided mandala coloring group (i.e., same as Experiment 1), or, to a mindfulness-guided coloring group (i.e., same as the unguided coloring group with a mindfulness practitioner guiding participants as in mindfulness breathing meditation, with instructions modified and applied to coloring). Results indicated that the mindfulness-guided mandala coloring group performed better in decreasing anxiety, but no change was observed in mindfulness. Exit interviews revealed that some participants did not like the voice guiding them while coloring, which suggested further differing and significant findings. While mindfulness-guided coloring appears promising, guidance or instructions on how to color mindfully may require further development and adjustment to enhance health and wellbeing.

Mechanical properties and biocompatibility of porous titanium scaffolds for bone tissue engineering.

Science.gov (United States)

Chen, Yunhui; Frith, Jessica Ellen; Dehghan-Manshadi, Ali; Attar, Hooyar; Kent, Damon; Soro, Nicolas Dominique Mathieu; Bermingham, Michael J; Dargusch, Matthew S

2017-11-01

Synthetic scaffolds are a highly promising new approach to replace both autografts and allografts to repair and remodel damaged bone tissue. Biocompatible porous titanium scaffold was manufactured through a powder metallurgy approach. Magnesium powder was used as space holder material which was compacted with titanium powder and removed during sintering. Evaluation of the porosity and mechanical properties showed a high level of compatibility with human cortical bone. Interconnectivity between pores is higher than 95% for porosity as low as 30%. The elastic moduli are 44.2GPa, 24.7GPa and 15.4GPa for 30%, 40% and 50% porosity samples which match well to that of natural bone (4-30GPa). The yield strengths for 30% and 40% porosity samples of 221.7MPa and 117MPa are superior to that of human cortical bone (130-180MPa). In-vitro cell culture tests on the scaffold samples using Human Mesenchymal Stem Cells (hMSCs) demonstrated their biocompatibility and indicated osseointegration potential. The scaffolds allowed cells to adhere and spread both on the surface and inside the pore structures. With increasing levels of porosity/interconnectivity, improved cell proliferation is obtained within the pores. It is concluded that samples with 30% porosity exhibit the best biocompatibility. The results suggest that porous titanium scaffolds generated using this manufacturing route have excellent potential for hard tissue engineering applications. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Mind of Consciousness

Indian Academy of Sciences (India)

Human mind, often considered synonymous ... between the monoists who believe that mind ... mental process in its own right, as widespread ... real challenge for experimental scientists is to devise ... several books like "The Minds of Robots",.

Composite PLA/PEG/nHA/Dexamethasone Scaffold Prepared by 3D Printing for Bone Regeneration.

Science.gov (United States)

Li, Xiaoyuan; Wang, Yu; Wang, Zigui; Qi, Yanxin; Li, Linlong; Zhang, Peibiao; Chen, Xuesi; Huang, Yubin

2018-04-24

3D printing has become an essential part of bone tissue engineering and attracts great attention for the fabrication of bioactive scaffolds. Combining this rapid manufacturing technique with chemical precipitation, biodegradable 3D scaffold composed of polymer matrix (polylactic acid and polyethylene glycol), ceramics (nano hydroxyapatite), and drugs (dexamethasone (Dex)) is prepared. Results of water contact angle, differential scanning calorimeter, and mechanical tests confirm that incorporation of Dex leads to significantly improved wettability, higher crystallinity degree, and tunable degradation rates. In vitro experiment with mouse MC3T3-E1 cells implies that Dex released from scaffolds is not beneficial for early cell proliferation, but it improves late alkaline phosphatase secretion and mineralization significantly. Anti-inflammation assay of murine RAW 264.7 cells proves that Dex released from all the scaffolds successfully suppresses lipopolysaccharide induced interleukin-6 and inducible nitric oxide synthase secretion by M1 macrophages. Further in vivo experiment on rat calvarial defects indicates that scaffolds containing Dex promote osteoinduction and osteogenic response and would be promising candidates for clinical applications. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Tubular inverse opal scaffolds for biomimetic vessels

Science.gov (United States)

Zhao, Ze; Wang, Jie; Lu, Jie; Yu, Yunru; Fu, Fanfan; Wang, Huan; Liu, Yuxiao; Zhao, Yuanjin; Gu, Zhongze

2016-07-01

There is a clinical need for tissue-engineered blood vessels that can be used to replace or bypass damaged arteries. The success of such grafts depends strongly on their ability to mimic native arteries; however, currently available artificial vessels are restricted by their complex processing, controversial integrity, or uncontrollable cell location and orientation. Here, we present new tubular scaffolds with specific surface microstructures for structural vessel mimicry. The tubular scaffolds are fabricated by rotationally expanding three-dimensional tubular inverse opals that are replicated from colloidal crystal templates in capillaries. Because of the ordered porous structure of the inverse opals, the expanded tubular scaffolds are imparted with circumferentially oriented elliptical pattern microstructures on their surfaces. It is demonstrated that these tailored tubular scaffolds can effectively make endothelial cells to form an integrated hollow tubular structure on their inner surface and induce smooth muscle cells to form a circumferential orientation on their outer surface. These features of our tubular scaffolds make them highly promising for the construction of biomimetic blood vessels.There is a clinical need for tissue-engineered blood vessels that can be used to replace or bypass damaged arteries. The success of such grafts depends strongly on their ability to mimic native arteries; however, currently available artificial vessels are restricted by their complex processing, controversial integrity, or uncontrollable cell location and orientation. Here, we present new tubular scaffolds with specific surface microstructures for structural vessel mimicry. The tubular scaffolds are fabricated by rotationally expanding three-dimensional tubular inverse opals that are replicated from colloidal crystal templates in capillaries. Because of the ordered porous structure of the inverse opals, the expanded tubular scaffolds are imparted with circumferentially

Teenaged Internet Tutors' Use of Scaffolding with Older Learners

Science.gov (United States)

Tambaum, Tiina

2017-01-01

This study analyses how teenaged instructors paired with older learners make use of scaffolding. Video data were categorised according to 15 types of direct scaffolding tactics, indirect scaffolding, and unused scaffolding opportunities. The results show that a teenager who is unprepared for the role of an instructor of Internet skills for older…

Acute Effects of Online Mind-Body Skills Training on Resilience, Mindfulness, and Empathy.

Science.gov (United States)

Kemper, Kathi J; Khirallah, Michael

2015-10-01

Some studies have begun to show benefits of brief in-person mind-body skills training. We evaluated the effects of 1-hour online elective mind-body skills training for health professionals on mindfulness, resilience, and empathy. Between May and November, 2014, we described enrollees for the most popular 1-hour modules in a new online mind-body skills training program; compared enrollees' baseline stress and burnout to normative samples; and assessed acute changes in mindfulness, resilience, and empathy. The 513 enrollees included dietitians, nurses, physicians, social workers, clinical trainees, and health researchers; about 1/4 were trainees. The most popular modules were the following: Introduction to Stress, Resilience, and the Relaxation Response (n = 261); Autogenic Training (n = 250); Guided Imagery and Hypnosis for Pain, Insomnia, and Changing Habits (n = 112); Introduction to Mindfulness (n = 112); and Mindfulness in Daily Life (n = 102). Initially, most enrollees met threshold criteria for burnout and reported moderate to high stress levels. Completing 1-hour modules was associated with significant acute improvements in stress (P training reaches diverse, stressed health professionals and is associated with acute improvements in stress, mindfulness, empathy, and resilience. Additional research is warranted to compare the long-term cost-effectiveness of different doses of online and in-person mind-body skills training for health professionals. © The Author(s) 2015.

Silk fibroin porous scaffolds for nucleus pulposus tissue engineering

International Nuclear Information System (INIS)

Zeng, Chao; Yang, Qiang; Zhu, Meifeng; Du, Lilong; Zhang, Jiamin; Ma, Xinlong; Xu, Baoshan; Wang, Lianyong

2014-01-01

Intervertebral discs (IVDs) are structurally complex tissue that hold the vertebrae together and provide mobility to spine. The nucleus pulposus (NP) degeneration often results in degenerative IVD disease that is one of the most common causes of back and neck pain. Tissue engineered nucleus pulposus offers an alternative approach to regain the function of the degenerative IVD. The aim of this study is to determine the feasibility of porous silk fibroin (SF) scaffolds fabricated by paraffin-sphere-leaching methods with freeze-drying in the application of nucleus pulposus regeneration. The prepared scaffold possessed high porosity of 92.38 ± 5.12% and pore size of 165.00 ± 8.25 μm as well as high pore interconnectivity and appropriate mechanical properties. Rabbit NP cells were seeded and cultured on the SF scaffolds. Scanning electron microscopy, histology, biochemical assays and mechanical tests revealed that the porous scaffolds could provide an appropriate microstructure and environment to support adhesion, proliferation and infiltration of NP cells in vitro as well as the generation of extracellular matrix. The NP cell–scaffold construction could be preliminarily formed after subcutaneously implanted in a nude mice model. In conclusion, The SF porous scaffold offers a potential candidate for tissue engineered NP tissue. - Highlights: • Paraffin microsphere-leaching method is used to fabricate silk fibroin scaffold. • The scaffold has appropriate mechanical property, porosity and pore size • The scaffold supports growth and infiltration of nucleus pulposus cells. • Nucleus pulposus cells can secrete extracellular matrix in the scaffolds. • The scaffold is a potential candidate for tissue engineered nucleus pulposus

Silk fibroin porous scaffolds for nucleus pulposus tissue engineering

Energy Technology Data Exchange (ETDEWEB)

Zeng, Chao; Yang, Qiang [Department of Spine Surgery, Tianjin Hospital, Tianjin 300211 (China); Tianjin Medical University, Tianjin 300070 (China); Zhu, Meifeng [The Key Laboratory of Bioactive Materials, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071 (China); Du, Lilong [Department of Spine Surgery, Tianjin Hospital, Tianjin 300211 (China); Tianjin Medical University, Tianjin 300070 (China); Zhang, Jiamin [The Key Laboratory of Bioactive Materials, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071 (China); Ma, Xinlong [Department of Spine Surgery, Tianjin Hospital, Tianjin 300211 (China); Xu, Baoshan, E-mail: xubaoshan99@126.com [Department of Spine Surgery, Tianjin Hospital, Tianjin 300211 (China); Wang, Lianyong, E-mail: wly@nankai.edu.cn [The Key Laboratory of Bioactive Materials, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071 (China)

2014-04-01

Intervertebral discs (IVDs) are structurally complex tissue that hold the vertebrae together and provide mobility to spine. The nucleus pulposus (NP) degeneration often results in degenerative IVD disease that is one of the most common causes of back and neck pain. Tissue engineered nucleus pulposus offers an alternative approach to regain the function of the degenerative IVD. The aim of this study is to determine the feasibility of porous silk fibroin (SF) scaffolds fabricated by paraffin-sphere-leaching methods with freeze-drying in the application of nucleus pulposus regeneration. The prepared scaffold possessed high porosity of 92.38 ± 5.12% and pore size of 165.00 ± 8.25 μm as well as high pore interconnectivity and appropriate mechanical properties. Rabbit NP cells were seeded and cultured on the SF scaffolds. Scanning electron microscopy, histology, biochemical assays and mechanical tests revealed that the porous scaffolds could provide an appropriate microstructure and environment to support adhesion, proliferation and infiltration of NP cells in vitro as well as the generation of extracellular matrix. The NP cell–scaffold construction could be preliminarily formed after subcutaneously implanted in a nude mice model. In conclusion, The SF porous scaffold offers a potential candidate for tissue engineered NP tissue. - Highlights: • Paraffin microsphere-leaching method is used to fabricate silk fibroin scaffold. • The scaffold has appropriate mechanical property, porosity and pore size • The scaffold supports growth and infiltration of nucleus pulposus cells. • Nucleus pulposus cells can secrete extracellular matrix in the scaffolds. • The scaffold is a potential candidate for tissue engineered nucleus pulposus.

Scaffold hopping in drug discovery using inductive logic programming.

Science.gov (United States)

Tsunoyama, Kazuhisa; Amini, Ata; Sternberg, Michael J E; Muggleton, Stephen H

2008-05-01

In chemoinformatics, searching for compounds which are structurally diverse and share a biological activity is called scaffold hopping. Scaffold hopping is important since it can be used to obtain alternative structures when the compound under development has unexpected side-effects. Pharmaceutical companies use scaffold hopping when they wish to circumvent prior patents for targets of interest. We propose a new method for scaffold hopping using inductive logic programming (ILP). ILP uses the observed spatial relationships between pharmacophore types in pretested active and inactive compounds and learns human-readable rules describing the diverse structures of active compounds. The ILP-based scaffold hopping method is compared to two previous algorithms (chemically advanced template search, CATS, and CATS3D) on 10 data sets with diverse scaffolds. The comparison shows that the ILP-based method is significantly better than random selection while the other two algorithms are not. In addition, the ILP-based method retrieves new active scaffolds which were not found by CATS and CATS3D. The results show that the ILP-based method is at least as good as the other methods in this study. ILP produces human-readable rules, which makes it possible to identify the three-dimensional features that lead to scaffold hopping. A minor variant of a rule learnt by ILP for scaffold hopping was subsequently found to cover an inhibitor identified by an independent study. This provides a successful result in a blind trial of the effectiveness of ILP to generate rules for scaffold hopping. We conclude that ILP provides a valuable new approach for scaffold hopping.

Development of a novel collagen-GAG nanofibrous scaffold via electrospinning

Energy Technology Data Exchange (ETDEWEB)

Zhong Shaoping [Department of Chemical and Biomolecular Engineering, National University of Singapore, 10 Kent Ridge Crescent 119260 (Singapore); Teo, Wee Eong [Division of Bioengineering, National University of Singapore, 10 Kent Ridge Crescent 119260 (Singapore); Zhu Xiao [Singapore Eye Research Institute, Singapore National Eye Center, 11 Third Hospital Avenue, Singapore 168751 (Singapore); Beuerman, Roger [Singapore Eye Research Institute, Singapore National Eye Center, 11 Third Hospital Avenue, Singapore 168751 (Singapore); Ramakrishna, Seeram [Division of Bioengineering, National University of Singapore, 10 Kent Ridge Crescent 119260 (Singapore); Yung, Lin Yue Lanry [Department of Chemical and Biomolecular Engineering, National University of Singapore, 10 Kent Ridge Crescent 119260 (Singapore)]. E-mail: cheyly@nus.edu.sg

2007-03-15

Collagen and glycosaminoglycan (GAG) are native constituents of human tissues and are widely utilized to fabricate scaffolds serving as an analog of native extracellular matrix (ECM).The development of blended collagen and GAG scaffolds may potentially be used in many soft tissue engineering applications since the scaffolds mimic the structure and biological function of native ECM. In this study, we were able to obtain a novel nanofibrous collagen-GAG scaffold by electrospinning with collagen and chondroitin sulfate (CS), a widely used GAG. The electrospun collagen-GAG scaffold exhibited a uniform fiber structure in nano-scale diameter. By crosslinking with glutaraldehyde vapor, the collagen-GAG scaffolds could resist from collagenase degradation and enhance the biostability of the scaffolds. This led to the increased proliferation of rabbit conjunctiva fibroblast on the scaffolds. Incorporation of CS into collagen nanofibers without crosslinking did not increase the biostability but still promoted cell growth. In conclusion, the electrospun collagen-GAG scaffolds, with high surface-to-volume ratio, may potentially provide a better environment for tissue formation/biosynthesis compared with the traditional scaffolds.

Development of a novel collagen-GAG nanofibrous scaffold via electrospinning

International Nuclear Information System (INIS)

Zhong Shaoping; Teo, Wee Eong; Zhu Xiao; Beuerman, Roger; Ramakrishna, Seeram; Yung, Lin Yue Lanry

2007-01-01

Collagen and glycosaminoglycan (GAG) are native constituents of human tissues and are widely utilized to fabricate scaffolds serving as an analog of native extracellular matrix (ECM).The development of blended collagen and GAG scaffolds may potentially be used in many soft tissue engineering applications since the scaffolds mimic the structure and biological function of native ECM. In this study, we were able to obtain a novel nanofibrous collagen-GAG scaffold by electrospinning with collagen and chondroitin sulfate (CS), a widely used GAG. The electrospun collagen-GAG scaffold exhibited a uniform fiber structure in nano-scale diameter. By crosslinking with glutaraldehyde vapor, the collagen-GAG scaffolds could resist from collagenase degradation and enhance the biostability of the scaffolds. This led to the increased proliferation of rabbit conjunctiva fibroblast on the scaffolds. Incorporation of CS into collagen nanofibers without crosslinking did not increase the biostability but still promoted cell growth. In conclusion, the electrospun collagen-GAG scaffolds, with high surface-to-volume ratio, may potentially provide a better environment for tissue formation/biosynthesis compared with the traditional scaffolds

Strategies for osteochondral repair: Focus on scaffolds

Directory of Open Access Journals (Sweden)

Seog-Jin Seo

2014-07-01

Full Text Available Interest in osteochondral repair has been increasing with the growing number of sports-related injuries, accident traumas, and congenital diseases and disorders. Although therapeutic interventions are entering an advanced stage, current surgical procedures are still in their infancy. Unlike other tissues, the osteochondral zone shows a high level of gradient and interfacial tissue organization between bone and cartilage, and thus has unique characteristics related to the ability to resist mechanical compression and restoration. Among the possible therapies, tissue engineering of osteochondral tissues has shown considerable promise where multiple approaches of utilizing cells, scaffolds, and signaling molecules have been pursued. This review focuses particularly on the importance of scaffold design and its role in the success of osteochondral tissue engineering. Biphasic and gradient composition with proper pore configurations are the basic design consideration for scaffolds. Surface modification is an essential technique to improve the scaffold function associated with cell regulation or delivery of signaling molecules. The use of functional scaffolds with a controllable delivery strategy of multiple signaling molecules is also considered a promising therapeutic approach. In this review, we updated the recent advances in scaffolding approaches for osteochondral tissue engineering.

A review: fabrication of porous polyurethane scaffolds.

Science.gov (United States)

Janik, H; Marzec, M

2015-03-01

The aim of tissue engineering is the fabrication of three-dimensional scaffolds that can be used for the reconstruction and regeneration of damaged or deformed tissues and organs. A wide variety of techniques have been developed to create either fibrous or porous scaffolds from polymers, metals, composite materials and ceramics. However, the most promising materials are biodegradable polymers due to their comprehensive mechanical properties, ability to control the rate of degradation and similarities to natural tissue structures. Polyurethanes (PUs) are attractive candidates for scaffold fabrication, since they are biocompatible, and have excellent mechanical properties and mechanical flexibility. PU can be applied to various methods of porous scaffold fabrication, among which are solvent casting/particulate leaching, thermally induced phase separation, gas foaming, emulsion freeze-drying and melt moulding. Scaffold properties obtained by these techniques, including pore size, interconnectivity and total porosity, all depend on the thermal processing parameters, and the porogen agent and solvents used. In this review, various polyurethane systems for scaffolds are discussed, as well as methods of fabrication, including the latest developments, and their advantages and disadvantages. Copyright © 2014. Published by Elsevier B.V.

Tantalum coating on porous Ti6Al4V scaffold using chemical vapor deposition and preliminary biological evaluation

Energy Technology Data Exchange (ETDEWEB)

Li, Xiang, E-mail: xiangliwj@sjtu.edu.cn [School of Mechanical Engineering, Shanghai Jiao Tong University, State Key Laboratory of Mechanical System and Vibration, Shanghai, 200240 (China); Wang, Lin [Institute of Orthopaedics, Xijing Hospital, The Fourth Military Medical University, Xi' an, 710032 (China); Yu, Xiaoming [The Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016 (China); Feng, Yafei [Institute of Orthopaedics, Xijing Hospital, The Fourth Military Medical University, Xi' an, 710032 (China); Wang, Chengtao [School of Mechanical Engineering, Shanghai Jiao Tong University, State Key Laboratory of Mechanical System and Vibration, Shanghai, 200240 (China); Yang, Ke [The Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016 (China); Su, Daniel [School of Mechanical Engineering, Shanghai Jiao Tong University, State Key Laboratory of Mechanical System and Vibration, Shanghai, 200240 (China)

2013-07-01

Porous tantalum (Ta), produced via chemical vapor deposition (CVD) of commercially pure Ta onto a vitreous carbon, is currently available for use in orthopedic applications. However, the relatively high manufacturing cost and the incapability to produce customized implant using medical image data have limited its application to gain widespread acceptance. In this study, Ta film was deposited on porous Ti6Al4V scaffolds using CVD technique. Digital microscopy and scanning electron microscopy indicated that the Ta coating evenly covered the entire scaffold structure. X-ray diffraction analysis showed that the coating consisted of α and β phases of Ta. Goat mesenchymal stem cells were seeded and cultured on the Ti6Al4V scaffolds with and without coating. The tetrazolium-based colorimetric assay exhibited better cell adhesion and proliferation on Ta-coated scaffolds compared with uncoated scaffolds. The porous scaffolds were subsequently implanted in goats for 12 weeks. Histological analysis revealed similar bone formation around the periphery of the coated and uncoated implants, but bone ingrowth is better within the Ta-coated scaffolds. To demonstrate the ability of producing custom implant for clinical applications via this technology, we designed and fabricated a porous Ti6Al4V scaffold with segmental mandibular shape derived from patient computerized tomography data. - Highlights: • Ta film was coated on porous Ti6Al4V scaffold using chemical vapor deposition. • Tantalum coating allowed for higher levels of cell adhesion and proliferation. • Better new bone formation occurred inside the tantalum-coated scaffolds. • Clinical image data was integrated with EBM to fabricate customized scaffold.

Tantalum coating on porous Ti6Al4V scaffold using chemical vapor deposition and preliminary biological evaluation

International Nuclear Information System (INIS)

Li, Xiang; Wang, Lin; Yu, Xiaoming; Feng, Yafei; Wang, Chengtao; Yang, Ke; Su, Daniel

2013-01-01

Porous tantalum (Ta), produced via chemical vapor deposition (CVD) of commercially pure Ta onto a vitreous carbon, is currently available for use in orthopedic applications. However, the relatively high manufacturing cost and the incapability to produce customized implant using medical image data have limited its application to gain widespread acceptance. In this study, Ta film was deposited on porous Ti6Al4V scaffolds using CVD technique. Digital microscopy and scanning electron microscopy indicated that the Ta coating evenly covered the entire scaffold structure. X-ray diffraction analysis showed that the coating consisted of α and β phases of Ta. Goat mesenchymal stem cells were seeded and cultured on the Ti6Al4V scaffolds with and without coating. The tetrazolium-based colorimetric assay exhibited better cell adhesion and proliferation on Ta-coated scaffolds compared with uncoated scaffolds. The porous scaffolds were subsequently implanted in goats for 12 weeks. Histological analysis revealed similar bone formation around the periphery of the coated and uncoated implants, but bone ingrowth is better within the Ta-coated scaffolds. To demonstrate the ability of producing custom implant for clinical applications via this technology, we designed and fabricated a porous Ti6Al4V scaffold with segmental mandibular shape derived from patient computerized tomography data. - Highlights: • Ta film was coated on porous Ti6Al4V scaffold using chemical vapor deposition. • Tantalum coating allowed for higher levels of cell adhesion and proliferation. • Better new bone formation occurred inside the tantalum-coated scaffolds. • Clinical image data was integrated with EBM to fabricate customized scaffold

Attachment, Proliferation, and Morphological Properties of Human Dermal Fibroblasts on Ovine Tendon Collagen Scaffolds: A Comparative Study.

Science.gov (United States)

Busra, Fauzi Mh; Lokanathan, Yogeswaran; Nadzir, Masrina Mohd; Saim, Aminuddin; Idrus, Ruszymah Bt Hj; Chowdhury, Shiplu Roy

2017-03-01

Collagen type I is widely used as a biomaterial for tissue-engineered substitutes. This study aimed to fabricate different three-dimensional (3D) scaffolds using ovine tendon collagen type I (OTC-I), and compare the attachment, proliferation and morphological features of human dermal fibroblasts (HDF) on the scaffolds. This study was conducted between the years 2014 to 2016 at the Tissue Engineering Centre, UKM Medical Centre. OTC-I was extracted from ovine tendon, and fabricated into 3D scaffolds in the form of sponge, hydrogel and film. A polystyrene surface coated with OTC-I was used as the 2D culture condition. Genipin was used to crosslink the OTC-I. A non-coated polystyrene surface was used as a control. The mechanical strength of OTC-I scaffolds was evaluated. Attachment, proliferation and morphological features of HDF were assessed and compared between conditions. The mechanical strength of OTC-I sponge was significantly higher than that of the other scaffolds. OTC-I scaffolds and the coated surface significantly enhanced HDF attachment and proliferation compared to the control, but no differences were observed between the scaffolds and coated surface. In contrast, the morphological features of HDF including spreading, filopodia, lamellipodia and actin cytoskeletal formation differed between conditions. OTC-I can be moulded into various scaffolds that are biocompatible and thus could be suitable as scaffolds for developing tissue substitutes for clinical applications and in vitro tissue models. However, further study is required to determine the effect of morphological properties on the functional and molecular properties of HDF.

Three-dimensional plotted hydroxyapatite scaffolds with predefined architecture: comparison of stabilization by alginate cross-linking versus sintering.

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Kumar, Alok; Akkineni, Ashwini R; Basu, Bikramjit; Gelinsky, Michael

2016-03-01

Scaffolds for bone tissue engineering are essentially characterized by porous three-dimensional structures with interconnected pores to facilitate the exchange of nutrients and removal of waste products from cells, thereby promoting cell proliferation in such engineered scaffolds. Although hydroxyapatite is widely being considered for bone tissue engineering applications due to its occurrence in the natural extracellular matrix of this tissue, limited reports are available on additive manufacturing of hydroxyapatite-based materials. In this perspective, hydroxyapatite-based three-dimensional porous scaffolds with two different binders (maltodextrin and sodium alginate) were fabricated using the extrusion method of three-dimensional plotting and the results were compared in reference to the structural properties of scaffolds processed via chemical stabilization and sintering routes, respectively. With the optimal processing conditions regarding to pH and viscosity of binder-loaded hydroxyapatite pastes, scaffolds with parallelepiped porous architecture having up to 74% porosity were fabricated. Interestingly, sintering of the as-plotted hydroxyapatite-sodium alginate (cross-linked with CaCl2 solution) scaffolds led to the formation of chlorapatite (Ca9.54P5.98O23.8Cl1.60(OH)2.74). Both the sintered scaffolds displayed progressive deformation and delayed fracture under compressive loading, with hydroxyapatite-alginate scaffolds exhibiting a higher compressive strength (9.5 ± 0.5 MPa) than hydroxyapatite-maltodextrin scaffolds (7.0 ± 0.6 MPa). The difference in properties is explained in terms of the phase assemblage and microstructure. © The Author(s) 2015.

2-N, 6-O-sulfated chitosan-assisted BMP-2 immobilization of PCL scaffolds for enhanced osteoinduction

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Cao, Lingyan [Key Laboratory for Ultrafine Materials of Ministry of Education, East China University of Science and Technology, Shanghai 200237 (China); Engineering Research Center for Biomedical Materials of Ministry of Education, East China University of Science and Technology, Shanghai 200237 (China); CSIRO Manufacturing, Bayview Avenue, Clayton, Victoria 3168 (Australia); Department of Prosthodontics, College of Stomatology, Ninth People' s Hospital, School of Medicine, Shanghai Jiao Tong University, 639 Zhizaoju Road, Shanghai 200011 (China); Yu, Yuanman [Key Laboratory for Ultrafine Materials of Ministry of Education, East China University of Science and Technology, Shanghai 200237 (China); Engineering Research Center for Biomedical Materials of Ministry of Education, East China University of Science and Technology, Shanghai 200237 (China); Wang, Jing, E-mail: biomatwj@163.com [Key Laboratory for Ultrafine Materials of Ministry of Education, East China University of Science and Technology, Shanghai 200237 (China); Engineering Research Center for Biomedical Materials of Ministry of Education, East China University of Science and Technology, Shanghai 200237 (China); Werkmeister, Jerome A [CSIRO Manufacturing, Bayview Avenue, Clayton, Victoria 3168 (Australia); McLean, Keith M, E-mail: Keith.McLean@csiro.au [CSIRO Manufacturing, Bayview Avenue, Clayton, Victoria 3168 (Australia); Liu, Changsheng, E-mail: liucs@ecust.edu.cn [Key Laboratory for Ultrafine Materials of Ministry of Education, East China University of Science and Technology, Shanghai 200237 (China); Engineering Research Center for Biomedical Materials of Ministry of Education, East China University of Science and Technology, Shanghai 200237 (China)

2017-05-01

The aim of this study was to develop a 2-N, 6-O-sulfated chitosan (26SCS) modified electrospun fibrous PCL scaffold for bone morphogenetic protein-2 (BMP-2) delivery to improve osteoinduction. The PCL scaffold was modified by an aminolysis reaction using ethylenediamine (ED) and 26SCS was immobilized via electrostatic interactions (PCL-N-S). Scaffolds were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and contact angle measurements. In vitro BMP-2 adsorption and release kinetics indicated that modified PCL-N-S scaffolds showed higher levels of binding of BMP-2 (about 30–100 times), moderative burst release (about one third), and prolonged releasing time compared to the unmodified PCL scaffold. The bioactivity of released BMP-2 determined by alkaline phosphatase (ALP) activity assay was maintained and improved 8– 12 times with increasing concentration of immobilized 26SCS on the scaffolds. In vitro studies demonstrated that bone marrow mesenchymal stem cells (BMSCs) attached more readily to the PCL-N-S scaffolds with increased spreading. In conclusion, 26SCS modified PCL scaffolds can be a potent system for the sustained and bioactive delivery of BMP-2. - Graphical abstract: Limited self-regenerating capacity of human body makes the reconstruction of critical size bone defect a significant challenge. Although bone morphogenetic protein-2 (BMP-2) is an important differentiation factor inducing bone regeneration, it's short half-life in vivo and potent side effect at high dosage still show lots of concerns in the clinical use. Herein, modification of electrospun PCL scaffolds was presented through immobilizing of sulfated chitosan (26SCS). The modified scaffolds effectively improve the binding capacity of BMP-2 and exhibited an enhanced bioactivity and sustained release in vitro. Thus, the use of 26SCS modified PCL scaffolds combined with BMP-2 could be a useful scaffold for tissue

Scaffold library for tissue engineering: a geometric evaluation.

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Chantarapanich, Nattapon; Puttawibul, Puttisak; Sucharitpwatskul, Sedthawatt; Jeamwatthanachai, Pongnarin; Inglam, Samroeng; Sitthiseripratip, Kriskrai

2012-01-01

Tissue engineering scaffold is a biological substitute that aims to restore, to maintain, or to improve tissue functions. Currently available manufacturing technology, that is, additive manufacturing is essentially applied to fabricate the scaffold according to the predefined computer aided design (CAD) model. To develop scaffold CAD libraries, the polyhedrons could be used in the scaffold libraries development. In this present study, one hundred and nineteen polyhedron models were evaluated according to the established criteria. The proposed criteria included considerations on geometry, manufacturing feasibility, and mechanical strength of these polyhedrons. CAD and finite element (FE) method were employed as tools in evaluation. The result of evaluation revealed that the close-cellular scaffold included truncated octahedron, rhombicuboctahedron, and rhombitruncated cuboctahedron. In addition, the suitable polyhedrons for using as open-cellular scaffold libraries included hexahedron, truncated octahedron, truncated hexahedron, cuboctahedron, rhombicuboctahedron, and rhombitruncated cuboctahedron. However, not all pore size to beam thickness ratios (PO:BT) were good for making the open-cellular scaffold. The PO:BT ratio of each library, generating the enclosed pore inside the scaffold, was excluded to avoid the impossibility of material removal after the fabrication. The close-cellular libraries presented the constant porosity which is irrespective to the different pore sizes. The relationship between PO:BT ratio and porosity of open-cellular scaffold libraries was displayed in the form of Logistic Power function. The possibility of merging two different types of libraries to produce the composite structure was geometrically evaluated in terms of the intersection index and was mechanically evaluated by means of FE analysis to observe the stress level. The couples of polyhedrons presenting low intersection index and high stress level were excluded. Good couples for

Scaffold Library for Tissue Engineering: A Geometric Evaluation

Directory of Open Access Journals (Sweden)

Nattapon Chantarapanich

2012-01-01

Full Text Available Tissue engineering scaffold is a biological substitute that aims to restore, to maintain, or to improve tissue functions. Currently available manufacturing technology, that is, additive manufacturing is essentially applied to fabricate the scaffold according to the predefined computer aided design (CAD model. To develop scaffold CAD libraries, the polyhedrons could be used in the scaffold libraries development. In this present study, one hundred and nineteen polyhedron models were evaluated according to the established criteria. The proposed criteria included considerations on geometry, manufacturing feasibility, and mechanical strength of these polyhedrons. CAD and finite element (FE method were employed as tools in evaluation. The result of evaluation revealed that the close-cellular scaffold included truncated octahedron, rhombicuboctahedron, and rhombitruncated cuboctahedron. In addition, the suitable polyhedrons for using as open-cellular scaffold libraries included hexahedron, truncated octahedron, truncated hexahedron, cuboctahedron, rhombicuboctahedron, and rhombitruncated cuboctahedron. However, not all pore size to beam thickness ratios (PO : BT were good for making the open-cellular scaffold. The PO : BT ratio of each library, generating the enclosed pore inside the scaffold, was excluded to avoid the impossibility of material removal after the fabrication. The close-cellular libraries presented the constant porosity which is irrespective to the different pore sizes. The relationship between PO : BT ratio and porosity of open-cellular scaffold libraries was displayed in the form of Logistic Power function. The possibility of merging two different types of libraries to produce the composite structure was geometrically evaluated in terms of the intersection index and was mechanically evaluated by means of FE analysis to observe the stress level. The couples of polyhedrons presenting low intersection index and high stress

Chitosan scaffolds induce human dental pulp stem cells to neural differentiation: potential roles for spinal cord injury therapy.

Science.gov (United States)

Zhang, Jinlong; Lu, Xiaohui; Feng, Guijuan; Gu, Zhifeng; Sun, Yuyu; Bao, Guofeng; Xu, Guanhua; Lu, Yuanzhou; Chen, Jiajia; Xu, Lingfeng; Feng, Xingmei; Cui, Zhiming

2016-10-01

Cell-based transplantation strategies hold great potential for spinal cord injury (SCI) repair. Chitosan scaffolds have therapeutic benefits for spinal cord regeneration. Human dental pulp stem cells (DPSCs) are abundant available stem cells with low immunological incompatibility and can be considered for cell replacement therapy. The purpose of this study is to investigate the role of chitosan scaffolds in the neural differentiation of DPSCs in vitro and to assess the supportive effects of chitosan scaffolds in an animal model of SCI. DPSCs were incubated with chitosan scaffolds. Cell viability and the secretion of neurotrophic factors were analyzed. DPSCs incubated with chitosan scaffolds were treated with neural differentiation medium for 14 days and then neural genes and protein markers were analyzed by Western blot and reverse transcription plus the polymerase chain reaction. Our study revealed a higher cell viability and neural differentiation in the DPSC/chitosan-scaffold group. Compared with the control group, the levels of BDNF, GDNF, b-NGF, and NT-3 were significantly increased in the DPSC/chitosan-scaffold group. The Wnt/β-catenin signaling pathway played a key role in the neural differentiation of DPSCs combined with chitosan scaffolds. Transplantation of DPSCs together with chitosan scaffolds into an SCI rat model resulted in the marked recovery of hind limb locomotor functions. Thus, chitosan scaffolds were non-cytotoxic and provided a conducive and favorable microenvironment for the survival and neural differentiation of DPSCs. Transplantation of DPSCs might therefore be a suitable candidate for treating SCI and other neuronal degenerative diseases.

Role of Demyelination Efficiency within Acellular Nerve Scaffolds during Nerve Regeneration across Peripheral Defects

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Meiqin Cai

2017-01-01

Full Text Available Hudson’s optimized chemical processing method is the most commonly used chemical method to prepare acellular nerve scaffolds for the reconstruction of large peripheral nerve defects. However, residual myelin attached to the basal laminar tube has been observed in acellular nerve scaffolds prepared using Hudson’s method. Here, we describe a novel method of producing acellular nerve scaffolds that eliminates residual myelin more effectively than Hudson’s method through the use of various detergent combinations of sulfobetaine-10, sulfobetaine-16, Triton X-200, sodium deoxycholate, and peracetic acid. In addition, the efficacy of this new scaffold in repairing a 1.5 cm defect in the sciatic nerve of rats was examined. The modified method produced a higher degree of demyelination than Hudson’s method, resulting in a minor host immune response in vivo and providing an improved environment for nerve regeneration and, consequently, better functional recovery. A morphological study showed that the number of regenerated axons in the modified group and Hudson group did not differ. However, the autograft and modified groups were more similar in myelin sheath regeneration than the autograft and Hudson groups. These results suggest that the modified method for producing a demyelinated acellular scaffold may aid functional recovery in general after nerve defects.

Embroidered polymer-collagen hybrid scaffold variants for ligament tissue engineering.

Science.gov (United States)

Hoyer, M; Drechsel, N; Meyer, M; Meier, C; Hinüber, C; Breier, A; Hahner, J; Heinrich, G; Rentsch, C; Garbe, L-A; Ertel, W; Schulze-Tanzil, G; Lohan, A

2014-10-01

Embroidery techniques and patterns used for scaffold production allow the adaption of biomechanical scaffold properties. The integration of collagen into embroidered polylactide-co-caprolactone [P(LA-CL)] and polydioxanone (PDS) scaffolds could stimulate neo-tissue formation by anterior cruciate ligament (ACL) cells. Therefore, the aim of this study was to test embroidered P(LA-CL) and PDS scaffolds as hybrid scaffolds in combination with collagen hydrogel, sponge or foam for ligament tissue engineering. ACL cells were cultured on embroidered P(LA-CL) and PDS scaffolds without or with collagen supplementation. Cell adherence, vitality, morphology and ECM synthesis were analyzed. Irrespective of thread size, ACL cells seeded on P(LA-CL) scaffolds without collagen adhered and spread over the threads, whereas the cells formed clusters on PDS and larger areas remained cell-free. Using the collagen hydrogel, the scaffold colonization was limited by the gel instability. The collagen sponge layers integrated into the scaffolds were hardly penetrated by the cells. Collagen foams increased scaffold colonization in P(LA-CL) but did not facilitate direct cell-thread contacts in the PDS scaffolds. The results suggest embroidered P(LA-CL) scaffolds as a more promising basis for tissue engineering an ACL substitute than PDS due to superior cell attachment. Supplementation with a collagen foam presents a promising functionalization strategy. Copyright © 2014 Elsevier B.V. All rights reserved.

[Mechanical properties of polylactic acid/beta-tricalcium phosphate composite scaffold with double channels based on three-dimensional printing technique].

Science.gov (United States)

Lian, Qin; Zhuang, Pei; Li, Changhai; Jin, Zhongmin; Li, Dichen

2014-03-01

To improve the poor mechanical strength of porous ceramic scaffold, an integrated method based on three-dimensional (3-D) printing technique is developed to incorporate the controlled double-channel porous structure into the polylactic acid/beta-tricalcium phosphate (PLA/beta-TCP) reinforced composite scaffolds (double-channel composite scaffold) to improve their tissue regeneration capability and the mechanical properties. The designed double-channel structure inside the ceramic scaffold consisted of both primary and secondary micropipes, which parallel but un-connected. The set of primary channels was used for cell ingrowth, while the set of secondary channels was used for the PLA perfusion. Integration technology of 3-D printing technique and gel-casting was firstly used to fabricate the double-channel ceramic scaffolds. PLA/beta-TCP composite scaffolds were obtained by the polymer gravity perfusion process to pour PLA solution into the double-channel ceramic scaffolds through the secondary channel set. Microscope, porosity, and mechanical experiments for the standard samples were used to evaluate the composite properties. The ceramic scaffold with only the primary channel (single-channel scaffold) was also prepared as a control. Morphology observation results showed that there was no PLA inside the primary channels of the double-channel composite scaffolds but a dense interface layer between PLA and beta-TCP obviously formed on the inner wall of the secondary channels by the PLA penetration during the perfusion process. Finite element simulation found that the compressive strength of the double-channel composite scaffold was less than that of the single-channel scaffold; however, mechanical tests found that the maximum compressive strength of the double-channel composite scaffold [(21.25 +/- 1.15) MPa] was higher than that of the single-channel scaffold[ (9.76 +/- 0.64) MPa]. The double-channel composite scaffolds fabricated by 3-D printing technique have

Scaffolds in regenerative endodontics: A review

Science.gov (United States)

Gathani, Kinjal M.; Raghavendra, Srinidhi Surya

2016-01-01

Root canal therapy has enabled us to save numerous teeth over the years. The most desired outcome of endodontic treatment would be when diseased or nonvital pulp is replaced with healthy pulp tissue that would revitalize the teeth through regenerative endodontics. ‘A search was conducted using the Pubmed and MEDLINE databases for articles with the criteria ‘Platelet rich plasma’, ‘Platelet rich fibrin’, ‘Stem cells’, ‘Natural and artificial scaffolds’ from 1982–2015’. Tissues are organized as three-dimensional structures, and appropriate scaffolding is necessary to provide a spatially correct position of cell location and regulate differentiation, proliferation, or metabolism of the stem cells. Extracellular matrix molecules control the differentiation of stem cells, and an appropriate scaffold might selectively bind and localize cells, contain growth factors, and undergo biodegradation over time. Different scaffolds facilitate the regeneration of different tissues. To ensure a successful regenerative procedure, it is essential to have a thorough and precise knowledge about the suitable scaffold for the required tissue. This article gives a review on the different scaffolds providing an insight into the new developmental approaches on the horizon. PMID:27857762

Scaffolds in regenerative endodontics: A review

Directory of Open Access Journals (Sweden)

Kinjal M Gathani

2016-01-01

Full Text Available Root canal therapy has enabled us to save numerous teeth over the years. The most desired outcome of endodontic treatment would be when diseased or nonvital pulp is replaced with healthy pulp tissue that would revitalize the teeth through regenerative endodontics. ′A search was conducted using the Pubmed and MEDLINE databases for articles with the criteria ′Platelet rich plasma′, ′Platelet rich fibrin′, ′Stem cells′, ′Natural and artificial scaffolds′ from 1982-2015′. Tissues are organized as three-dimensional structures, and appropriate scaffolding is necessary to provide a spatially correct position of cell location and regulate differentiation, proliferation, or metabolism of the stem cells. Extracellular matrix molecules control the differentiation of stem cells, and an appropriate scaffold might selectively bind and localize cells, contain growth factors, and undergo biodegradation over time. Different scaffolds facilitate the regeneration of different tissues. To ensure a successful regenerative procedure, it is essential to have a thorough and precise knowledge about the suitable scaffold for the required tissue. This article gives a review on the different scaffolds providing an insight into the new developmental approaches on the horizon.

Designing, Prototyping and Evaluating Digital Mindfulness Applications: A Case Study of Mindful Breathing for Stress Reduction.

Science.gov (United States)

Zhu, Bin; Hedman, Anders; Feng, Shuo; Li, Haibo; Osika, Walter

2017-06-14

silent and sonified HU. The mean value of HR using silent HU was significantly lower than resting baseline and sonified HU. The mean value of root mean square of differences (RMSSD) using silent HU was significantly higher than resting baseline. We found that the differences between our objective and subjective assessments were intriguing and prompted us to investigate them further. Our evaluation of HU indicated that HU could facilitate relaxed breathing and stress reduction. There was a difference in outcome between the physiological measures of stress and the subjective reports of stress, as well as a large intervariability among study participants. Our conclusion is that the use of stress reduction tools should be customized and that the design work of mindfulness technology for stress reduction is a complex process, which requires cooperation of designers, HCI (Human-Computer Interaction) experts and clinicians. ©Bin Zhu, Anders Hedman, Shuo Feng, Haibo Li, Walter Osika. Originally published in the Journal of Medical Internet Research (http://www.jmir.org), 14.06.2017.

Mindfulness in cultural context.

Science.gov (United States)

Kirmayer, Laurence J

2015-08-01

Mindfulness meditation and other techniques drawn from Buddhism have increasingly been integrated into forms of psychotherapeutic intervention. In much of this work, mindfulness is understood as a mode of awareness that is present-centered and nonevaluative. This form of awareness is assumed to have intrinsic value in promoting positive mental health and adaptation by interrupting discursive thoughts that give rise to suffering. However, in the societies where it originated, mindfulness meditation is part of a larger system of Buddhist belief and practice with strong ethical and moral dimensions. Extracting techniques like mindfulness meditation from the social contexts in which they originate may change the nature and effects of the practice. The papers in this issue of Transcultural Psychiatry explore the implications of a cultural and contextual view of mindfulness for continued dialogue between Buddhist thought and psychiatry. This introductory essay considers the meanings of mindfulness meditation in cultural context and the uses of mindfulness as a therapeutic intervention in contemporary psychiatry and psychology. © The Author(s) 2015.

Synergistic Effect of Carbon Nanotubes and Graphene on Diopside Scaffolds.

Science.gov (United States)

Liu, Tingting; Wu, Ping; Gao, Chengde; Feng, Pei; Xiao, Tao; Deng, Youwen; Shuai, Cijun; Peng, Shuping

2016-01-01

A synergetic effect between carbon nanotubes (CNTs) and graphene on diopside (Di) scaffolds was demonstrated. 3D network architecture in the matrix was formed through the 1D CNTs inlaid among the 2D graphene platelets (GNPs). The mechanical properties of the CNTs/GNPs/Di scaffolds were significantly improved compared with the CNTs/Di scaffolds and GNPs/Di scaffolds. In addition, the scaffolds exhibited excellent apatite-forming ability, a modest degradation rate, and stable mechanical properties in simulated body fluid (SBF). Moreover, cell culturing tests indicated that the scaffolds supported the cells attachment and proliferation. Taken together, the CNTs/GNPs/Di scaffolds offered great potential for bone tissue engineering.

Examining the factors that are correlated with mindfulness with a focus on attention deficit hyperactivity symptoms.

Science.gov (United States)

Yavuz, Burcu Goksan; Yavuz, Mesut; Onal, Arzu

2018-05-18

We hypothesized that attention deficit hyperactivity symptoms would negatively correlate with the level of mindfulness. Seventy-six subjects referred to the outpatient psychiatry unit and 32 healthy control subjects filled out the Mindful Attention Awareness Scale (MAAS), the Depression Anxiety Stress Scale (DASS), the Adult ADHD Self-Report Scale (ASRS), and the Wender Utah Rating Scale (WURS). Patients scored higher on ADH symptoms compared to controls (p ≤ .001). Higher scores on the ASRS and WURS revealed lower mindfulness in the study group (p ≤ .001). WURS, DASS depression, ASRS attention subscale-based scores (p < .05) were significant predictors on MAAS scores. Besides emotional symptoms ADH symptoms had a significant predictive value on mindfulness. © 2018 Wiley Periodicals, Inc.

Whole mind and shared mind in clinical decision-making.

Science.gov (United States)

Epstein, Ronald Mark

2013-02-01

To review the theory, research evidence and ethical implications regarding "whole mind" and "shared mind" in clinical practice in the context of chronic and serious illnesses. Selective critical review of the intersection of classical and naturalistic decision-making theories, cognitive neuroscience, communication research and ethics as they apply to decision-making and autonomy. Decision-making involves analytic thinking as well as affect and intuition ("whole mind") and sharing cognitive and affective schemas of two or more individuals ("shared mind"). Social relationships can help processing of complex information that otherwise would overwhelm individuals' cognitive capacities. Medical decision-making research, teaching and practice should consider both analytic and non-analytic cognitive processes. Further, research should consider that decisions emerge not only from the individual perspectives of patients, their families and clinicians, but also the perspectives that emerge from the interactions among them. Social interactions have the potential to enhance individual autonomy, as well as to promote relational autonomy based on shared frames of reference. Shared mind has the potential to result in wiser decisions, greater autonomy and self-determination; yet, clinicians and patients should be vigilant for the potential of hierarchical relationships to foster coercion or silencing of the patient's voice. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

When Did Coloring Books Become Mindful? Exploring the Effectiveness of a Novel Method of Mindfulness-Guided Instructions for Coloring Books to Increase Mindfulness and Decrease Anxiety

Directory of Open Access Journals (Sweden)

Michail Mantzios

2018-01-01

Full Text Available Mindfulness has been associated with the use of coloring books for adults; however, the question of whether they do increase mindfulness has not been addressed. In two studies, we attempted to identify whether mindfulness is increased, and whether there is a need for ongoing guidance while coloring, similar to mindfulness meditation. In the first randomized controlled experiment, university students (n = 88 were assigned to an unguided mandala coloring group (i.e., described in mainstream literature as a mindfulness practice or to a free-drawing group. Measurements of state mindfulness and state anxiety were taken pre- and post- experiment. Results indicated no change in mindfulness or anxiety. In the second randomized controlled experiment, university students (n = 72 were assigned to an unguided mandala coloring group (i.e., same as Experiment 1, or, to a mindfulness-guided coloring group (i.e., same as the unguided coloring group with a mindfulness practitioner guiding participants as in mindfulness breathing meditation, with instructions modified and applied to coloring. Results indicated that the mindfulness-guided mandala coloring group performed better in decreasing anxiety, but no change was observed in mindfulness. Exit interviews revealed that some participants did not like the voice guiding them while coloring, which suggested further differing and significant findings. While mindfulness-guided coloring appears promising, guidance or instructions on how to color mindfully may require further development and adjustment to enhance health and wellbeing.

Mindfulness for unge

DEFF Research Database (Denmark)

Nielsen, Anne Maj

Undersøgelsen af, hvordan interventionsforløbet Mindfulness for unge virkede, er baseret på kvalitative interview med 24 elever i 9. klasse, som har deltaget i Mindfulness for unge i 8 uger. Resultater: Det fælles mindfulnessforløb i klassen har lært mange af eleverne at kunne bruge deres bevidste...... opmærksomhed til at forholde sig til deres situation, tilstand og muligheder, så de udvikler deres ressourcer i stedet for at blive fanget i afmagt og stress. Det er oplevelser og erfaringer med de praktiske mindfulness-øvelser, der har været særlig betydningsfuldt. Overordnet ser Mindfulness for unge ud til...... at kunne bidrage til at forebygge stress i skolen for en del elever, når mindfulness-instruktørens undervisning følges op og faciliteres af en mindfulnesspraktiserende lærer, der kender klassen og eleverne godt. Interesse og opbakning fra skolens ledelse og elevernes familier er også væsentligt...

Mindful innovation

DEFF Research Database (Denmark)

Olsen, Poul Bitsch

2008-01-01

Mindful innovation is an approach to innovation that pays attention to people's experience in an organization rather than to formal organization or social role.......Mindful innovation is an approach to innovation that pays attention to people's experience in an organization rather than to formal organization or social role....

Fabrication and Mechanical Characterization of Hydrogel Infused Network Silk Scaffolds

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Lakshminath Kundanati

2016-09-01

Full Text Available Development and characterization of porous scaffolds for tissue engineering and regenerative medicine is of great importance. In recent times, silk scaffolds were developed and successfully tested in tissue engineering and drug release applications. We developed a novel composite scaffold by mechanical infusion of silk hydrogel matrix into a highly porous network silk scaffold. The mechanical behaviour of these scaffolds was thoroughly examined for their possible use in load bearing applications. Firstly, unconfined compression experiments show that the denser composite scaffolds displayed significant enhancement in the elastic modulus as compared to either of the components. This effect was examined and further explained with the help of foam mechanics principles. Secondly, results from confined compression experiments that resemble loading of cartilage in confinement, showed nonlinear material responses for all scaffolds. Finally, the confined creep experiments were performed to calculate the hydraulic permeability of the scaffolds using soil mechanics principles. Our results show that composite scaffolds with some modifications can be a potential candidate for use of cartilage like applications. We hope such approaches help in developing novel scaffolds for tissue engineering by providing an understanding of the mechanics and can further be used to develop graded scaffolds by targeted infusion in specific regions.

Gelatin–PMVE/MA composite scaffold promotes expansion of embryonic stem cells

International Nuclear Information System (INIS)

Chhabra, Hemlata; Gupta, Priyanka; Verma, Paul J.; Jadhav, Sameer; Bellare, Jayesh R.

2014-01-01

We introduce a new composite scaffold of gelatin and polymethyl vinyl ether-alt-maleic anhydride (PMVE/MA) for expansion of embryonic stem cells (ESCs) in an in vitro environment. To optimize the scaffold, we prepared a gelatin scaffold (G) and three composite scaffolds namely GP-1, GP-2, and GP-3 with varying PMVE/MA concentrations (0.2–1%) and characterized them by scanning electron microscopy (SEM), swelling study, compression testing and FTIR. SEM micrographs revealed interconnected porous structure in all the scaffolds. The permissible hemolysis ratio and activation of platelets by scaffolds confirmed the hemocompatibility of scaffolds. Initial biocompatibility assessment of scaffolds was conducted using hepatocarcinoma (Hep G2) cells and adhesion, proliferation and infiltration of Hep G2 cells in depth of scaffolds were observed, proving the scaffold's biocompatibility. Further Oct4B2 mouse embryonic stem cells (mESCs), which harbor a green fluorescence protein transgene under regulatory control of the Oct4 promotor, were examined for expansion on scaffolds with MTT assay. The GP-2 scaffold demonstrated the best cell proliferation and was further explored for ESC adherence and infiltration in depth (SEM and confocal), and pluripotent state of mESCs was assessed with the expression of Oct4-GFP and stage-specific embryonic antigen-1 (SSEA-1). This study reports the first demonstration of biocompatibility of gelatin–PMVE/MA composite scaffold and presents this scaffold as a promising candidate for embryonic stem cell based tissue engineering. - Highlights: • Composite scaffolds of gelatin and PMVE/MA were prepared by freeze-drying method. • SEM micrographs showed porous structure in all scaffolds of varying pore dimension. • GP-2 composite exhibited better cellular response in comparison to other scaffolds. • mESCs proliferated and expressed Oct-4 and SSEA-1, when cultured on GP-2 scaffold

Gelatin–PMVE/MA composite scaffold promotes expansion of embryonic stem cells

Energy Technology Data Exchange (ETDEWEB)

Chhabra, Hemlata [Department of Chemical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai (India); Gupta, Priyanka [Department of Chemical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai (India); IITB-Monash Research Academy, Mumbai (India); Department of Chemical Engineering, Monash University, Melbourne (Australia); Verma, Paul J. [Turretfield Research Centre, South Australian Research and Development Institute, Rosedale, South Australia (Australia); Jadhav, Sameer; Bellare, Jayesh R. [Department of Chemical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai (India)

2014-04-01

We introduce a new composite scaffold of gelatin and polymethyl vinyl ether-alt-maleic anhydride (PMVE/MA) for expansion of embryonic stem cells (ESCs) in an in vitro environment. To optimize the scaffold, we prepared a gelatin scaffold (G) and three composite scaffolds namely GP-1, GP-2, and GP-3 with varying PMVE/MA concentrations (0.2–1%) and characterized them by scanning electron microscopy (SEM), swelling study, compression testing and FTIR. SEM micrographs revealed interconnected porous structure in all the scaffolds. The permissible hemolysis ratio and activation of platelets by scaffolds confirmed the hemocompatibility of scaffolds. Initial biocompatibility assessment of scaffolds was conducted using hepatocarcinoma (Hep G2) cells and adhesion, proliferation and infiltration of Hep G2 cells in depth of scaffolds were observed, proving the scaffold's biocompatibility. Further Oct4B2 mouse embryonic stem cells (mESCs), which harbor a green fluorescence protein transgene under regulatory control of the Oct4 promotor, were examined for expansion on scaffolds with MTT assay. The GP-2 scaffold demonstrated the best cell proliferation and was further explored for ESC adherence and infiltration in depth (SEM and confocal), and pluripotent state of mESCs was assessed with the expression of Oct4-GFP and stage-specific embryonic antigen-1 (SSEA-1). This study reports the first demonstration of biocompatibility of gelatin–PMVE/MA composite scaffold and presents this scaffold as a promising candidate for embryonic stem cell based tissue engineering. - Highlights: • Composite scaffolds of gelatin and PMVE/MA were prepared by freeze-drying method. • SEM micrographs showed porous structure in all scaffolds of varying pore dimension. • GP-2 composite exhibited better cellular response in comparison to other scaffolds. • mESCs proliferated and expressed Oct-4 and SSEA-1, when cultured on GP-2 scaffold.

ASTM International Workshop on Standards & Measurements for Tissue Engineering Scaffolds

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Simon, Carl G.; Yaszemski, Michael J.; Ratcliffe, Anthony; Tomlins, Paul; Luginbuehl, Reto; Tesk, John A.

2016-01-01

The “Workshop on Standards & Measurements for Tissue Engineering Scaffolds” was held on May 21, 2013 in Indianapolis, IN and was sponsored by the ASTM International (ASTM). The purpose of the workshop was to identify the highest priority items for future standards work for scaffolds used in the development and manufacture of tissue engineered medical products (TEMPs). Eighteen speakers and 78 attendees met to assess current scaffold standards and to prioritize needs for future standards. A key finding was that the ASTM TEMPs subcommittees (F04.41-46) have many active “guide” documents for educational purposes, but that few standard “test methods” or “practices” have been published. Overwhelmingly, the most clearly identified need was standards for measuring the structure of scaffolds, followed by standards for biological characterization, including in vitro testing, animal models and cell-material interactions. The third most pressing need was to develop standards for assessing the mechanical properties of scaffolds. Additional needs included standards for assessing scaffold degradation, clinical outcomes with scaffolds, effects of sterilization on scaffolds, scaffold composition and drug release from scaffolds. Discussions also highlighted the need for additional scaffold reference materials and the need to use them for measurement traceability. Finally, dialogue emphasized the needs to promote the use of standards in scaffold fabrication, characterization, and commercialization and to assess the use and impact of standards in the TEMPs community. Many scaffold standard needs have been identified and focus should now turn to generating these standards to support the use of scaffolds in TEMPs. PMID:25220952

Scaffold translation: barriers between concept and clinic.

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Hollister, Scott J; Murphy, William L

2011-12-01

Translation of scaffold-based bone tissue engineering (BTE) therapies to clinical use remains, bluntly, a failure. This dearth of translated tissue engineering therapies (including scaffolds) remains despite 25 years of research, research funding totaling hundreds of millions of dollars, over 12,000 papers on BTE and over 2000 papers on BTE scaffolds alone in the past 10 years (PubMed search). Enabling scaffold translation requires first an understanding of the challenges, and second, addressing the complete range of these challenges. There are the obvious technical challenges of designing, manufacturing, and functionalizing scaffolds to fill the Form, Fixation, Function, and Formation needs of bone defect repair. However, these technical solutions should be targeted to specific clinical indications (e.g., mandibular defects, spine fusion, long bone defects, etc.). Further, technical solutions should also address business challenges, including the need to obtain regulatory approval, meet specific market needs, and obtain private investment to develop products, again for specific clinical indications. Finally, these business and technical challenges present a much different model than the typical research paradigm, presenting the field with philosophical challenges in terms of publishing and funding priorities that should be addressed as well. In this article, we review in detail the technical, business, and philosophical barriers of translating scaffolds from Concept to Clinic. We argue that envisioning and engineering scaffolds as modular systems with a sliding scale of complexity offers the best path to addressing these translational challenges. © Mary Ann Liebert, Inc.

Trait mindfulness modulates neuroendocrine and affective responses to social evaluative threat.

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Brown, Kirk Warren; Weinstein, Netta; Creswell, J David

2012-12-01

Individual differences in mindfulness have been associated with numerous self-report indicators of stress, but research has not examined how mindfulness may buffer neuroendocrine and psychological stress responses under controlled laboratory conditions. The present study investigated the role of trait mindfulness in buffering cortisol and affective responses to a social evaluative stress challenge versus a control task. Participants completed measures of trait mindfulness, perceived stress, anxiety, and fear of negative evaluation before being randomized to complete the Trier Social Stress Test (TSST; Kirschbaum et al., 1993) or a control task. At points throughout the session, participants provided five saliva samples to assess cortisol response patterns, and completed four self-report measures of anxiety and negative affect to assess psychological responses. In accord with hypotheses, higher trait mindfulness predicted lower cortisol responses to the TSST, relative to the control task, as well as lower anxiety and negative affect. These relations remained significant when controlling for the role of other variables that predicted cortisol and affective responses. The findings suggest that trait mindfulness modulates cortisol and affective responses to an acute social stressor. Further research is needed to understand the neural pathways through which mindfulness impacts these responses. Copyright © 2012 Elsevier Ltd. All rights reserved.

Soy Protein Scaffold Biomaterials for Tissue Engineering and Regenerative Medicine

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Chien, Karen B.

Developing functional biomaterials using highly processable materials with tailorable physical and bioactive properties is an ongoing challenge in tissue engineering. Soy protein is an abundant, natural resource with potential use for regenerative medicine applications. Preliminary studies show that soy protein can be physically modified and fabricated into various biocompatible constructs. However, optimized soy protein structures for tissue regeneration (i.e. 3D porous scaffolds) have not yet been designed. Furthermore, little work has established the in vivo biocompatibility of implanted soy protein and the benefit of using soy over other proteins including FDA-approved bovine collagen. In this work, freeze-drying and 3D printing fabrication processes were developed using commercially available soy protein to create porous scaffolds that improve cell growth and infiltration compared to other soy biomaterials previously reported. Characterization of scaffold structure, porosity, and mechanical/degradation properties was performed. In addition, the behavior of human mesenchymal stem cells seeded on various designed soy scaffolds was analyzed. Biological characterization of the cell-seeded scaffolds was performed to assess feasibility for use in liver tissue regeneration. The acute and humoral response of soy scaffolds implanted in an in vivo mouse subcutaneous model was also investigated. All fabricated soy scaffolds were modified using thermal, chemical, and enzymatic crosslinking to change properties and cell growth behavior. 3D printing allowed for control of scaffold pore size and geometry. Scaffold structure, porosity, and degradation rate significantly altered the in vivo response. Freeze-dried soy scaffolds had similar biocompatibility as freeze-dried collagen scaffolds of the same protein content. However, the soy scaffolds degraded at a much faster rate, minimizing immunogenicity. Interestingly, subcutaneously implanted soy scaffolds affected blood

A Review on Fabricating Tissue Scaffolds using Vat Photopolymerization.

Science.gov (United States)

Chartrain, Nicholas A; Williams, Christopher B; Whittington, Abby R

2018-05-09

Vat Photopolymerization (stereolithography, SLA), an Additive Manufacturing (AM) or 3D printing technology, holds particular promise for the fabrication of tissue scaffolds for use in regenerative medicine. Unlike traditional tissue scaffold fabrication techniques, SLA is capable of fabricating designed scaffolds through the selective photopolymerization of a photopolymer resin on the micron scale. SLA offers unprecedented control over scaffold porosity and permeability, as well as pore size, shape, and interconnectivity. Perhaps even more significantly, SLA can be used to fabricate vascular networks that may encourage angio and vasculogenesis. Fulfilling this potential requires the development of new photopolymers, the incorporation of biochemical factors into printed scaffolds, and an understanding of the effects scaffold geometry have on cell viability, proliferation, and differentiation. This review compares SLA to other scaffold fabrication techniques, highlights significant advances in the field, and offers a perspective on the field's challenges and future directions. Engineering de novo tissues continues to be challenging due, in part, to our inability to fabricate complex tissue scaffolds that can support cell proliferation and encourage the formation of developed tissue. The goal of this review is to first introduce the reader to traditional and Additive Manufacturing scaffold fabrication techniques. The bulk of this review will then focus on apprising the reader of current research and provide a perspective on the promising use of vat photopolymerization (stereolithography, SLA) for the fabrication of complex tissue scaffolds. Copyright © 2018. Published by Elsevier Ltd.

Cell-matrix mechanical interaction in electrospun polymeric scaffolds for tissue engineering: Implications for scaffold design and performance.

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Kennedy, Kelsey M; Bhaw-Luximon, Archana; Jhurry, Dhanjay

2017-03-01

Engineered scaffolds produced by electrospinning of biodegradable polymers offer a 3D, nanofibrous environment with controllable structural, chemical, and mechanical properties that mimic the extracellular matrix of native tissues and have shown promise for a number of tissue engineering applications. The microscale mechanical interactions between cells and electrospun matrices drive cell behaviors including migration and differentiation that are critical to promote tissue regeneration. Recent developments in understanding these mechanical interactions in electrospun environments are reviewed, with emphasis on how fiber geometry and polymer structure impact on the local mechanical properties of scaffolds, how altering the micromechanics cues cell behaviors, and how, in turn, cellular and extrinsic forces exerted on the matrix mechanically remodel an electrospun scaffold throughout tissue development. Techniques used to measure and visualize these mechanical interactions are described. We provide a critical outlook on technological gaps that must be overcome to advance the ability to design, assess, and manipulate the mechanical environment in electrospun scaffolds toward constructs that may be successfully applied in tissue engineering and regenerative medicine. Tissue engineering requires design of scaffolds that interact with cells to promote tissue development. Electrospinning is a promising technique for fabricating fibrous, biomimetic scaffolds. Effects of electrospun matrix microstructure and biochemical properties on cell behavior have been extensively reviewed previously; here, we consider cell-matrix interaction from a mechanical perspective. Micromechanical properties as a driver of cell behavior has been well established in planar substrates, but more recently, many studies have provided new insights into mechanical interaction in fibrillar, electrospun environments. This review provides readers with an overview of how electrospun scaffold mechanics and

Scaling of Advanced Theory-of-Mind Tasks

Science.gov (United States)

Osterhaus, Christopher; Koerber, Susanne; Sodian, Beate

2016-01-01

Advanced theory-of-mind (AToM) development was investigated in three separate studies involving 82, 466, and 402 elementary school children (8-, 9-, and 10-year-olds). Rasch and factor analyses assessed whether common conceptual development underlies higher-order false-belief understanding, social understanding, emotion recognition, and…

Nano/macro porous bioactive glass scaffold

Science.gov (United States)

Wang, Shaojie

Bioactive glass (BG) and ceramics have been widely studied and developed as implants to replace hard tissues of the musculo-skeletal system, such as bones and teeth. Recently, instead of using bulk materials, which usually do not degrade rapidly enough and may remain in the human body for a long time, the idea of bioscaffold for tissue regeneration has generated much interest. An ideal bioscaffold is a porous material that would not only provide a three-dimensional structure for the regeneration of natural tissue, but also degrade gradually and, eventually be replaced by the natural tissue completely. Among various material choices the nano-macro dual porous BG appears as the most promising candidate for bioscaffold applications. Here macropores facilitate tissue growth while nanopores control degradation and enhance cell response. The surface area, which controls the degradation of scaffold can also be tuned by changing the nanopore size. However, fabrication of such 3D structure with desirable nano and macro pores has remained challenging. In this dissertation, sol-gel process combined with spinodal decomposition or polymer sponge replication method has been developed to fabricate the nano-macro porous BG scaffolds. Macropores up to 100microm are created by freezing polymer induced spinodal structure through sol-gel transition, while larger macropores (>200um) of predetermined size are obtained by the polymer sponge replication technique. The size of nanopores, which are inherent to the sol-gel method of glass fabrication, has been tailored using several approaches: Before gel point, small nanopores are generated using acid catalyst that leads to weakly-branched polymer-like network. On the other hand, larger nanopores are created with the base-catalyzed gel with highly-branched cluster-like structure. After the gel point, the nanostructure can be further modified by manipulating the sintering temperature and/or the ammonia concentration used in the solvent

The assessment of mindfulness skills: the "what" and the "how".

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Iani, Luca; Lauriola, Marco; Cafaro, Valentina

2017-10-06

The five facets mindfulness questionnaire-short form (FFMQ-SF) is a new, brief measure for the assessment of mindfulness skills in clinical and nonclinical samples. The construct validity of the FFMQ-SF has not been previously assessed in community samples. The present study investigated the factor structure of the Italian version of the FFMQ-SF. Structured equation modeling was used to test the fit of three alternative models in a sample of highly educated adults (n = 211). A hierarchical model with a single second-order factor loaded by observing, describing, and acting with awareness (i.e. the mindfulness "what" skills) performed slightly better than both a five-factor model with correlated factors and a hierarchical model with a general second-order factor. The FFMQ-SF scores were significantly higher than those reported in both Dutch depressed patients and Australian undergraduate students for all facets (but nonreactivity for the Australian sample). Data support the multifaceted nature of mindfulness skills. Because of its brevity and simplicity of use, the FFMQ-SF is a promising questionnaire in longitudinal and clinical research. This questionnaire can serve as a guideline to help clinicians assess and monitor mindfulness skills acquisition, strengthening, and generalization, and prioritize mindfulness skills that need immediate attention.

Mindful Parenting and Emotion Socialization Practices: Concurrent and Longitudinal Associations.

Science.gov (United States)

McKee, Laura G; Parent, Justin; Zachary, Chloe R; Forehand, Rex

2017-11-01

Caregivers play a crucial role in the socialization of youth emotion understanding, competence, and regulation, which are implicated in youth social and emotional health; however, there is less understanding of parental psychosocial or cognitive factors, like mindful parenting, that may be associated with the use of particular emotion socialization (ES) strategies. This study tests a model of the cross-sectional and short-term longitudinal associations between mindful parenting and supportive and nonsupportive ES strategies in a community sample of parents (N = 246; 63.8% mothers) of youth ranging from ages 3-12. Caregivers reported on mindful parenting and ES strategies at two time points 4 months apart. The structural equation model indicated that higher levels of mindful parenting are positively related to supportive ES responses and negatively related to nonsupportive ES responses both concurrently and over time. The longitudinal association between mindful parenting and nonsupportive, but not supportive, ES was marginally larger for fathers as compared to mothers. Given the documented impact of ES strategies on youth emotional and behavioral outcomes and interventions emerging to educate parents about how to provide a healthy emotional atmosphere, incorporating a focus on mindful parenting strategies may provide one pathway to increase supportive responses and decrease nonsupportive ones. © 2017 Family Process Institute.

Trait Mindfulness as a Limiting Factor for Residual Depressive Symptoms: An Explorative Study Using Quantile Regression

Science.gov (United States)

Radford, Sholto; Eames, Catrin; Brennan, Kate; Lambert, Gwladys; Crane, Catherine; Williams, J. Mark G.; Duggan, Danielle S.; Barnhofer, Thorsten

2014-01-01

Mindfulness has been suggested to be an important protective factor for emotional health. However, this effect might vary with regard to context. This study applied a novel statistical approach, quantile regression, in order to investigate the relation between trait mindfulness and residual depressive symptoms in individuals with a history of recurrent depression, while taking into account symptom severity and number of episodes as contextual factors. Rather than fitting to a single indicator of central tendency, quantile regression allows exploration of relations across the entire range of the response variable. Analysis of self-report data from 274 participants with a history of three or more previous episodes of depression showed that relatively higher levels of mindfulness were associated with relatively lower levels of residual depressive symptoms. This relationship was most pronounced near the upper end of the response distribution and moderated by the number of previous episodes of depression at the higher quantiles. The findings suggest that with lower levels of mindfulness, residual symptoms are less constrained and more likely to be influenced by other factors. Further, the limiting effect of mindfulness on residual symptoms is most salient in those with higher numbers of episodes. PMID:24988072

ALP gene expression in cDNA samples from bone tissue engineering using a HA/TCP/Chitosan scaffold

Science.gov (United States)

Stephanie, N.; Katarina, H.; Amir, L. R.; Gunawan, H. A.

2017-08-01

This study examined the potential use of hydroxyapatite (HA)/tricalcium phosphate (TCP)/Chitosan as a bone tissue engineering scaffold. The potential for using HA/TCP/chitosan as a scaffold was analyzed by measuring expression of the ALP osteogenic gene in cDNA from bone biopsies from four Macaque nemestrina. Experimental conditions included control (untreated), treatment with HA/TCP 70:30, HA/TCP 50:50, and HA/TCP/chitosan. cDNA samples were measured quantitively with Real-Time PCR (qPCR) and semi-quantitively by gel electrophoresis. There were no significant differences in ALP gene expression between treatment subjects after two weeks, but the HA/TCP/chitosan treatment gave the highest level of expression after four weeks. The scaffold using the HA/TCP/chitosan combination induced a higher level of expression of the osteogenic gene ALP than did scaffold without chitosan.

Toward a Framework on How Affordances and Motives Can Drive Different Uses of Scaffolds: Theory, Evidence, and Design Implications

Science.gov (United States)

Belland, Brian R.; Drake, Joel

2013-01-01

One way to help students engage in higher-order thinking is through scaffolding, which can be defined as support that allows students to participate meaningfully in and gain skill at a task that is beyond their unassisted abilities. Most research on computer-based scaffolds assesses the average impact of the tools on learning outcomes. This is…

Exact approaches for scaffolding

OpenAIRE

Weller, Mathias; Chateau, Annie; Giroudeau, Rodolphe

2015-01-01

This paper presents new structural and algorithmic results around the scaffolding problem, which occurs prominently in next generation sequencing. The problem can be formalized as an optimization problem on a special graph, the "scaffold graph". We prove that the problem is polynomial if this graph is a tree by providing a dynamic programming algorithm for this case. This algorithm serves as a basis to deduce an exact algorithm for general graphs using a tree decomposition of the input. We ex...

Mindfulness is associated with psychological health and moderates pain in knee osteoarthritis.

Science.gov (United States)

Lee, A C; Harvey, W F; Price, L L; Morgan, L P K; Morgan, N L; Wang, C

2017-06-01

Previous studies suggest that higher mindfulness is associated with less pain and depression. However, the role of mindfulness has never been studied in knee osteoarthritis (OA). We evaluate the relationships between mindfulness and pain, psychological symptoms, and quality of life in knee OA. We performed a secondary analysis of baseline data from our randomized comparative trial in participants with knee OA. Mindfulness was assessed using the Five Facet Mindfulness Questionnaire (FFMQ). We measured pain, physical function, quality of life, depression, stress, and self-efficacy with commonly-used patient-reported measures. Simple and multivariable regression models were utilized to assess associations between mindfulness and health outcomes. We further tested whether mindfulness moderated the pain-psychological outcome associations. Eighty patients were enrolled (60.3 ± 10.3 years; 76.3% female, body mass index: 33.0 ± 7.1 kg/m 2 ). Total mindfulness score was associated with mental (beta = 1.31, 95% CI: 0.68, 1.95) and physical (beta = 0.69, 95% CI:0.06, 1.31) component quality of life, self-efficacy (beta = 0.22, 95% CI:0.07, 0.37), depression (beta = -1.15, 95% CI:-1.77, -0.54), and stress (beta = -1.07, 95% CI:-1.53, -0.60). Of the five facets, the Describing, Acting-with-Awareness, and Non-judging mindfulness facets had the most associations with psychological health. No significant association was found between mindfulness and pain or function (P = 0.08-0.24). However, we found that mindfulness moderated the effect of pain on stress (P = 0.02). Mindfulness is associated with depression, stress, self-efficacy, and quality of life among knee OA patients. Mindfulness also moderates the influence of pain on stress, which suggests that mindfulness may alter the way one copes with pain. Future studies examining the benefits of mind-body therapy, designed to increase mindfulness, for patients with OA are warranted. Copyright © 2016

Scaffolding Proteins: Not Such Innocent Bystanders

OpenAIRE

Smith, F. Donelson; Scott, John D.

2013-01-01

Sequential transfer of information from one enzyme to the next within the confines of a protein kinase scaffold enhances signal transduction. Though frequently considered to be inert organizational elements, two recent reports implicate kinase-scaffolding proteins as active participants in signal relay.

The effect of porosity on cell ingrowth into accurately defined, laser-made, polylactide-based 3D scaffolds

Energy Technology Data Exchange (ETDEWEB)

Danilevicius, Paulius; Georgiadi, Leoni [Foundation for Research and Technology Hellas (FORTH), Institute of Electronic Structure and Laser (IESL), N Plastira 100, 70013 Heraklion (Greece); Pateman, Christopher J.; Claeyssens, Frederik [Kroto Research Institute, Department of Materials Science and Engineering, University of Sheffield, Broad Lane, Sheffield S3 7HQ (United Kingdom); Chatzinikolaidou, Maria, E-mail: mchatzin@materials.uoc.gr [Foundation for Research and Technology Hellas (FORTH), Institute of Electronic Structure and Laser (IESL), N Plastira 100, 70013 Heraklion (Greece); Department of Materials Science and Technology, University of Crete, PO Box 2208, 71303 Heraklion (Greece); Farsari, Maria, E-mail: mfarsari@iesl.forth.gr [Foundation for Research and Technology Hellas (FORTH), Institute of Electronic Structure and Laser (IESL), N Plastira 100, 70013 Heraklion (Greece)

2015-05-01

Highlights: • We studied the porosity of laser-made 3D scaffolds on MC3T3-E1 pre-osteoblastic cells. • We made polylactide 3D scaffolds with pores 25–110 μm. - Abstract: The aim of this study is to demonstrate the accuracy required for the investigation of the role of solid scaffolds’ porosity in cell proliferation. We therefore present a qualitative investigation into the effect of porosity on MC3T3-E1 pre-osteoblastic cell ingrowth of three-dimensional (3D) scaffolds fabricated by direct femtosecond laser writing. The material we used is a purpose made photosensitive pre-polymer based on polylactide. We designed and fabricated complex, geometry-controlled 3D scaffolds with pore sizes ranging from 25 to 110 μm, representing porosities 70%, 82%, 86%, and 90%. The 70% porosity scaffolds did not support cell growth initially and in the long term. For the other porosities, we found a strong adhesion of the pre-osteoblastic cells from the first hours after seeding and a remarkable proliferation increase after 3 weeks and up to 8 weeks. The 86% porosity scaffolds exhibited a higher efficiency compared to 82% and 90%. In addition, bulk material degradation studies showed that the employed, highly-acrylated polylactide is degradable. These findings support the potential use of the proposed material and the scaffold fabrication technique in bone tissue engineering.

It Takes Two to Tango: Towards Theory of AI's Mind

OpenAIRE

Chandrasekaran, Arjun; Yadav, Deshraj; Chattopadhyay, Prithvijit; Prabhu, Viraj; Parikh, Devi

2017-01-01

Theory of Mind is the ability to attribute mental states (beliefs, intents, knowledge, perspectives, etc.) to others and recognize that these mental states may differ from one's own. Theory of Mind is critical to effective communication and to teams demonstrating higher collective performance. To effectively leverage the progress in Artificial Intelligence (AI) to make our lives more productive, it is important for humans and AI to work well together in a team. Traditionally, there has been m...

Mechanical anisotropy of titanium scaffolds

Directory of Open Access Journals (Sweden)

Rüegg Jasmine

2017-09-01

Full Text Available The clinical performance of an implant, e.g. for the treatment of large bone defects, depends on the implant material, anchorage, surface topography and chemistry, but also on the mechanical properties, like the stiffness. The latter can be adapted by the porosity. Whereas foams show isotropic mechanical properties, digitally modelled scaffolds can be designed with anisotropic behaviour. In this study, we designed and produced 3D scaffolds based on an orthogonal architecture and studied its angle-dependent stiffness. The aim was to produce scaffolds with different orientations of the microarchitecture by selective laser melting and compare the angle-specific mechanical behaviour with an in-silico simulation. The anisotropic characteristics of open-porous implants and technical limitations of the production process were studied.

HA/nylon 6,6 porous scaffolds fabricated by salt-leaching/solvent casting technique: effect of nano-sized filler content on scaffold properties

Directory of Open Access Journals (Sweden)

Mehrabanian M

2011-08-01

Full Text Available Mehran Mehrabanian1, Mojtaba Nasr-Esfahani21Member of Young Researchers Club, Najafabad Branch, Islamic Azad University, Isfahan, Iran; 2Department of Materials Science and Engineering, Najafabad Branch, Islamic Azad University, Isfahan, IranAbstract: Nanohydroxyapatite (n-HA/nylon 6,6 composite scaffolds were produced by means of the salt-leaching/solvent casting technique. NaCl with a distinct range size was used with the aim of optimizing the pore network. Composite powders with different n-HA contents (40%, 60% for scaffold fabrication were synthesized and tested. The composite scaffolds thus obtained were characterized for their microstructure, mechanical stability and strength, and bioactivity. The microstructure of the composite scaffolds possessed a well-developed interconnected porosity with approximate optimal pore size ranging from 200 to 500 µm, ideal for bone regeneration and vascularization. The mechanical properties of the composite scaffolds were evaluated by compressive strength and modulus tests, and the results confirmed their similarity to cortical bone. To characterize bioactivity, the composite scaffolds were immersed in simulated body fluid for different lengths of time and results monitored by scanning electron microscopy and energy dispersive X-ray microanalysis to determine formation of an apatite layer on the scaffold surface.Keywords: scaffold, nanohydroxyapatite, nylon 6,6, salt-leaching/solvent casting, bioactivity

Porous 45S5 Bioglass®-based scaffolds using stereolithography: Effect of partial pre-sintering on structural and mechanical properties of scaffolds.

Science.gov (United States)

Thavornyutikarn, Boonlom; Tesavibul, Passakorn; Sitthiseripratip, Kriskrai; Chatarapanich, Nattapon; Feltis, Bryce; Wright, Paul F A; Turney, Terence W

2017-06-01

Scaffolds made from 45S5 Bioglass® ceramic (BG) show clinical potential in bone regeneration due to their excellent bioactivity and ability to bond to natural bone tissue. However, porous BG scaffolds are limited by their mechanical integrity and by the substantial volume contractions occurring upon sintering. This study examines stereolithographic (SLA) methods to fabricate mechanically robust and porous Bioglass®-based ceramic scaffolds, with regular and interconnected pore networks and using various computer-aided design architectures. It was found that a diamond-like (DM) architecture gave scaffolds the most controllable results without any observable closed porosity in the fired scaffolds. When the pore dimensions of the DM scaffolds of the same porosity (~60vol%) were decreased from 700 to 400μm, the compressive strength values increased from 3.5 to 6.7MPa. In addition, smaller dimensional shrinkage could be obtained by employing partially pre-sintered bioglass, compared to standard 45S5 Bioglass®. Scaffolds derived from pre-sintered bioglass also showed marginally improved compressive strength. Copyright © 2017 Elsevier B.V. All rights reserved.