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Sample records for cell broadband engine

  1. Implementation of Scientific Computing Applications on the Cell Broadband Engine

    Directory of Open Access Journals (Sweden)

    Guochun Shi

    2009-01-01

    Full Text Available The Cell Broadband Engine architecture is a revolutionary processor architecture well suited for many scientific codes. This paper reports on an effort to implement several traditional high-performance scientific computing applications on the Cell Broadband Engine processor, including molecular dynamics, quantum chromodynamics and quantum chemistry codes. The paper discusses data and code restructuring strategies necessary to adapt the applications to the intrinsic properties of the Cell processor and demonstrates performance improvements achieved on the Cell architecture. It concludes with the lessons learned and provides practical recommendations on optimization techniques that are believed to be most appropriate.

  2. Distributed Shared Memory for the Cell Broadband Engine (DSMCBE)

    DEFF Research Database (Denmark)

    Larsen, Morten Nørgaard; Skovhede, Kenneth; Vinter, Brian

    2009-01-01

    The CELL-BE processor provides high performance and has been shown to reach a performance close to the theoretical peak, however, the high performance comes at the price of a quite complex programming model. Central to the complexity of the CELL-BE programming model is the need to move data in and...... out of non-coherent local storage blocks for each special processor element. In this paper we present a software library, namely the Distributed Shared Memory for the Cell Broadband Engine (DSMCBE). By using techniques known from distributed shared memory DSMCBE allows programmers to program the CELL...

  3. Cell broadband engine architecture as a DSP platform

    Science.gov (United States)

    Szumski, Karol; Malanowski, Mateusz

    2009-06-01

    The slowing pace of performance improvement in the commonly available processors is a cause of concern amongst many computational scientists. This combined with the ever increasing need for computational power has caused us to turn to alternative architectures in search of performance gains. Two main candidates were the Compute Unified Device Architecture (CUDA) and the Cell Broadband Engine (CELL BE) architecture. This paper focuses on the latter, outlining the architecture and basic programming paradigms, and also contains performance comparison of algorithms currently developed by our team.

  4. Speech recognition systems on the Cell Broadband Engine

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Y; Jones, H; Vaidya, S; Perrone, M; Tydlitat, B; Nanda, A

    2007-04-20

    In this paper we describe our design, implementation, and first results of a prototype connected-phoneme-based speech recognition system on the Cell Broadband Engine{trademark} (Cell/B.E.). Automatic speech recognition decodes speech samples into plain text (other representations are possible) and must process samples at real-time rates. Fortunately, the computational tasks involved in this pipeline are highly data-parallel and can receive significant hardware acceleration from vector-streaming architectures such as the Cell/B.E. Identifying and exploiting these parallelism opportunities is challenging, but also critical to improving system performance. We observed, from our initial performance timings, that a single Cell/B.E. processor can recognize speech from thousands of simultaneous voice channels in real time--a channel density that is orders-of-magnitude greater than the capacity of existing software speech recognizers based on CPUs (central processing units). This result emphasizes the potential for Cell/B.E.-based speech recognition and will likely lead to the future development of production speech systems using Cell/B.E. clusters.

  5. Self-Organizing Maps on the Cell Broadband Engine Architecture

    International Nuclear Information System (INIS)

    We present and evaluate novel parallel implementations of Self-Organizing Maps for the Cell Broadband Engine Architecture. Motivated by the interactive nature of the data-mining process, we evaluate the scalability of the implementations on two clusters using different network characteristics and incarnations (PS3TMconsole and PowerXCell 8i) of the architecture. Our implementations use varying combinations of the Power Processing Elements (PPEs) and Synergistic Processing Elements (SPEs) found in the Cell architecture. For a single processor, our implementation scaled well with the number of SPEs regardless of the incarnation. When combining multiple PS3TMconsoles, the synchronization over the slower network resulted in poor speedups and demonstrated that the use of such a low-cost cluster may be severely restricted, even without the use of SPEs. When using multiple SPEs for the PowerXCell 8i cluster, the speedup grew linearly with increasing number of SPEs for a given number of processors, and linear up to a maximum with the number of processors for a given number of SPEs. Our implementation achieved a worst-case efficiency of 67% for the maximum number of processing elements involved in the computation, but consistently higher values for smaller numbers of processing elements with speedups of up to 70.

  6. LU Decomposition on Cell Broadband Engine: An Empirical Study to Exploit Heterogeneous Chip Multiprocessors

    OpenAIRE

    Mao, Feng; Shen, Xipeng

    2010-01-01

    To meet the needs of high performance computing, the Cell Broadband Engine owns many features that differ from traditional processors, such as the large number of synergistic processor elements, large register files, the ability to hide main-storage latency with concurrent computation and DMA transfers. The exploitation of those features requires the programmer to carefully tailor programs and simutaneously deal with various performance factors, including locality, load balance, communication...

  7. Parallel local search for solving Constraint Problems on the Cell Broadband Engine (Preliminary Results

    Directory of Open Access Journals (Sweden)

    Salvator Abreu

    2009-10-01

    Full Text Available We explore the use of the Cell Broadband Engine (Cell/BE for short for combinatorial optimization applications: we present a parallel version of a constraint-based local search algorithm that has been implemented on a multiprocessor BladeCenter machine with twin Cell/BE processors (total of 16 SPUs per blade. This algorithm was chosen because it fits very well the Cell/BE architecture and requires neither shared memory nor communication between processors, while retaining a compact memory footprint. We study the performance on several large optimization benchmarks and show that this achieves mostly linear time speedups, even sometimes super-linear. This is possible because the parallel implementation might explore simultaneously different parts of the search space and therefore converge faster towards the best sub-space and thus towards a solution. Besides getting speedups, the resulting times exhibit a much smaller variance, which benefits applications where a timely reply is critical.

  8. Streaming Model Based Volume Ray Casting Implementation for Cell Broadband Engine

    Directory of Open Access Journals (Sweden)

    Jusub Kim

    2009-01-01

    Full Text Available Interactive high quality volume rendering is becoming increasingly more important as the amount of more complex volumetric data steadily grows. While a number of volumetric rendering techniques have been widely used, ray casting has been recognized as an effective approach for generating high quality visualization. However, for most users, the use of ray casting has been limited to datasets that are very small because of its high demands on computational power and memory bandwidth. However the recent introduction of the Cell Broadband Engine (Cell B.E. processor, which consists of 9 heterogeneous cores designed to handle extremely demanding computations with large streams of data, provides an opportunity to put the ray casting into practical use. In this paper, we introduce an efficient parallel implementation of volume ray casting on the Cell B.E. The implementation is designed to take full advantage of the computational power and memory bandwidth of the Cell B.E. using an intricate orchestration of the ray casting computation on the available heterogeneous resources. Specifically, we introduce streaming model based schemes and techniques to efficiently implement acceleration techniques for ray casting on Cell B.E. In addition to ensuring effective SIMD utilization, our method provides two key benefits: there is no cost for empty space skipping and there is no memory bottleneck on moving volumetric data for processing. Our experimental results show that we can interactively render practical datasets on a single Cell B.E. processor.

  9. Efficient SIMDization and Data Management of the Lattice QCD Computation on the Cell Broadband Engine

    Directory of Open Access Journals (Sweden)

    Khaled Z. Ibrahim

    2009-01-01

    Full Text Available Lattice Quantum Chromodynamic (QCD models subatomic interactions based on a four-dimensional discretized space–time continuum. The Lattice QCD computation is one of the grand challenges in physics especially when modeling a lattice with small spacing. In this work, we study the implementation of the main kernel routine of Lattice QCD that dominates the execution time on the Cell Broadband Engine. We tackle the problem of efficient SIMD execution and the problem of limited bandwidth for data transfers with the off-chip memory. For efficient SIMD execution, we present runtime data fusion technique that groups data processed similarly at runtime. We also introduce analysis needed to reduce the pressure on the scarce memory bandwidth that limits the performance of this computation. We studied two implementations for the main kernel routine that exhibit different patterns of accessing the memory and thus allowing different sets of optimizations. We show the attributes that make one implementation more favorable in terms of performance. For lattice size that is significantly larger than the local store, our implementation achieves 31.2 GFlops for single precision computations and 16.6 GFlops for double precision computations on the PowerXCell 8i, an order of magnitude better than the performance achieved on most general-purpose processors.

  10. Accelerating the Execution of Matrix Languages on the Cell Broadband Engine Architecture

    CERN Document Server

    Khoury, Raymes; Scholz, Bernhard

    2009-01-01

    Matrix languages, including MATLAB and Octave, are established standards for applications in science and engineering. They provide interactive programming environments that are easy to use due to their script languages with matrix data types. Current implementations of matrix languages do not fully utilize high-performance, special-purpose chip architectures such as the IBM PowerXCell processor (Cell), which is currently used in the fastest computer in the world. We present a new framework that extends Octave to harvest the computational power of the Cell. With this framework the programmer is alleviated of the burden of introducing explicit notions of parallelism. Instead the programmer uses a new matrix data-type to execute matrix operations in parallel on the synergistic processing elements (SPEs) of the Cell. We employ lazy evaluation semantics for our new matrix data-type to obtain execution traces of matrix operations. Traces are converted to data dependence graphs; operations in the data dependence gra...

  11. Analyzing Use of OpenCL on the Cell Broadband Engine and a Proposal for OpenCL Extensions

    Directory of Open Access Journals (Sweden)

    Claudia Fohry

    2011-01-01

    Full Text Available

    Current processor architectures are diverse and heterogeneous. Examples include multicore chips, GPUs and the Cell Broadband Engine (CBE. The recent Open Compute Language (OpenCL standard aims at efficiency and portability. This paper explores its efficiency when implemented on the CBE, without using CBE-specific features such as explicit asynchronous memory transfers. We based our experiments on two applications: matrix multiplication, and the client side of the Einstein@Home distributed computing project. Both were programmed in OpenCL, and then translated to the CBE. For matrix multiplication, we deployed different levels of OpenCL performance optimization, and observed that they pay off on the CBE. For Einstein@Home, our translated OpenCL version achieves almost the same speed as a native CBE version. We experimented with two versions of the OpenCL to CBE mapping, in which the PPE component of the CBE does or does not take the role of a compute unit.

    Another major contribution of the paper is a proposal for two OpenCL extensions that we analyzed for both CBE and NVIDIA GPUs. First, we suggest an additional memory level in OpenCL, called static local memory. With little programming expense, it can lead to significant speedups such as for reduction a factor of seven on the CBE and about 20% on NVIDIA GPUs. Second, we introduce static work-groups to support user-defined mappings of tasks. Static work-groups may simplify programming and lead to speedups of 35% (CBE and 100% (GPU for all-parallel-prefix-sums.

  12. Broadband absorption engineering of hyperbolic metafilm patterns

    Science.gov (United States)

    Ji, Dengxin; Song, Haomin; Zeng, Xie; Hu, Haifeng; Liu, Kai; Zhang, Nan; Gan, Qiaoqiang

    2014-03-01

    Perfect absorbers are important optical/thermal components required by a variety of applications, including photon/thermal-harvesting, thermal energy recycling, and vacuum heat liberation. While there is great interest in achieving highly absorptive materials exhibiting large broadband absorption using optically thick, micro-structured materials, it is still challenging to realize ultra-compact subwavelength absorber for on-chip optical/thermal energy applications. Here we report the experimental realization of an on-chip broadband super absorber structure based on hyperbolic metamaterial waveguide taper array with strong and tunable absorption profile from near-infrared to mid-infrared spectral region. The ability to efficiently produce broadband, highly confined and localized optical fields on a chip is expected to create new regimes of optical/thermal physics, which holds promise for impacting a broad range of energy technologies ranging from photovoltaics, to thin-film thermal absorbers/emitters, to optical-chemical energy harvesting.

  13. Broadband absorption engineering of hyperbolic metafilm patterns

    OpenAIRE

    Ji, Dengxin; Song, Haomin; Zeng, Xie; Hu, Haifeng; Liu, Kai; Zhang, Nan; Gan, Qiaoqiang

    2014-01-01

    Perfect absorbers are important optical/thermal components required by a variety of applications, including photon/thermal-harvesting, thermal energy recycling, and vacuum heat liberation. While there is great interest in achieving highly absorptive materials exhibiting large broadband absorption using optically thick, micro-structured materials, it is still challenging to realize ultra-compact subwavelength absorber for on-chip optical/thermal energy applications. Here we report the experime...

  14. Broadband back grating design for thin film solar cells

    KAUST Repository

    Janjua, Bilal

    2013-01-01

    In this paper, design based on tapered circular grating structure was studied, to provide broadband enhancement in thin film amorphous silicon solar cells. In comparison to planar structure an absorption enhancement of ~ 7% was realized.

  15. Broadband metasurface holograms: toward complete phase and amplitude engineering.

    Science.gov (United States)

    Wang, Qiu; Zhang, Xueqian; Xu, Yuehong; Gu, Jianqiang; Li, Yanfeng; Tian, Zhen; Singh, Ranjan; Zhang, Shuang; Han, Jiaguang; Zhang, Weili

    2016-01-01

    As a revolutionary three-dimensional imaging technique, holography has attracted wide attention for its ability to photographically record a light field. However, traditional phase-only or amplitude-only modulation holograms have limited image quality and resolution to reappear both amplitude and phase information required of the objects. Recent advances in metasurfaces have shown tremendous opportunities for using a planar design of artificial meta-atoms to shape the wave front of light by optimal control of both its phase and amplitude. Inspired by the concept of designer metasurfaces, we demonstrate a novel amplitude-phase modulation hologram with simultaneous five-level amplitude modulation and eight-level phase modulation. Such a design approach seeks to turn the perceived disadvantages of the traditional phase or amplitude holograms, and thus enable enhanced performance in resolution, homogeneity of amplitude distribution, precision, and signal-to-noise ratio. In particular, the unique holographic approach exhibits broadband characteristics. The method introduced here delivers more degrees of freedom, and allows for encoding highly complex information into designer metasurfaces, thus having the potential to drive next-generation technological breakthroughs in holography. PMID:27615519

  16. Spectrally engineered broadband photon source for two-photon quantum interferometry

    CERN Document Server

    Thomas, Abu; Minaeva, Olga; Simon, David; Sergienko, Alexander V

    2016-01-01

    We present a new approach to engineering broadband sources of entangled photon pairs for quantum interferometry. The source is based on quasi-phase-matched spontaneous parametric down conversion in a titanium diffused periodically poled lithium niobate waveguide with a strongly-chirped poling period. The proposed non-standard asymmetric poling mitigates phase distortions associated with the process of chirping. Asymmetric poling significantly broadens the entangled source bandwidth while preserving high visibility quantum interferometric sensing.

  17. Cell and Tissue Engineering

    CERN Document Server

    2012-01-01

    Cell and Tissue Engineering” introduces the principles and new approaches in cell and tissue engineering. It includes both the fundamentals and the current trends in cell and tissue engineering, in a way useful both to a novice and an expert in the field. The book is composed of 13 chapters all of which are written by the leading experts. It is organized to gradually assemble an insight in cell and tissue function starting form a molecular nano-level, extending to a cellular micro-level and finishing at the tissue macro-level. In specific, biological, physiological, biophysical, biochemical, medical, and engineering aspects are covered from the standpoint of the development of functional substitutes of biological tissues for potential clinical use. Topics in the area of cell engineering include cell membrane biophysics, structure and function of the cytoskeleton, cell-extracellular matrix interactions, and mechanotransduction. In the area of tissue engineering the focus is on the in vitro cultivation of ...

  18. Editorial: Stem Cell Engineering.

    Science.gov (United States)

    Cabral, Joaquim M S; Palecek, Sean P

    2015-10-01

    In recent years, the promise of stem cells as tools for basic research, in vitro diagnostics, and in vivo therapeutics is increasingly being realized. This Special issue of Biotechnology Journal explores recent advances in the emerging field of stem cell engineering, with a focus on applying engineering approaches to understanding stem cell biology and enabling translation of stem cells to commercial and clinical products. PMID:26447639

  19. Cell Control Engineering

    DEFF Research Database (Denmark)

    Lynggaard, Hans Jørgen Birk; Alting, Leo

    1996-01-01

    The engineering process of creating cell control systems is described, and a Cell Control Engineering (CCE) concept is defined. The purpose is to assist people, representing different disciplines in the organisation, to implement cell controllers by addressing the complexity of having many systems...... in physically and logically different and changing manufacturing environments. The defined CCE concept combines state-of-the-art of commercially available enabling technologies for automation system software development, generic cell control models and guidelines for the complete engineering process....... It facilitates the understanding of the task and structure of cell controllers and uses this knowledge directly in the implementation of the system. By applying generic models CCE facilitates reuse of software components and maintenance of applications. In many enterprises, software makes up an...

  20. Optimization of broadband omnidirectional antireflection coatings for solar cells

    CERN Document Server

    Guo, Xia; Li, Chong; Zhou, Hongyi; Lv, Benshun; Feng, Yajie; Wang, Huaqiang; Liu, Wuming

    2015-01-01

    Broadband and omnidirectional antireflection coating is a generally effective way to improve solar cell efficiency, because the destructive interference between the reflected and input waves could maximize transmission light in the absorption layer. Several theoretical calculations have been developed to optimize the anti-reflective coating to maximize the average transmittance. However, the solar irradiances of the clear sky spectral direct beam on a receiver plane at different positions and times are variable greatly. Here we report a new theoretical calculation of anti-reflective coating with incident quantum efficiency {\\eta}in as evaluation function for practical application. The two-layer and three-layer anti-reflective coatings are optimized over {\\lambda} = [300, 1100] nm and {\\theta} = [0{\\deg}, 90{\\deg}] for cities of Quito, Beijing and Moscow. The {\\eta}in of two-layer anti-reflective coating increases by 0.26%, 1.37% and 4.24% for these 3 cities, respectively, compared with that other theoretical ...

  1. Fuel cell engineering

    CERN Document Server

    Sundmacher

    2012-01-01

    Fuel cells are attractive electrochemical energy converters featuring potentially very high thermodynamic efficiency factors. The focus of this volume of Advances in Chemical Engineering is on quantitative approaches, particularly based on chemical engineering principles, to analyze, control and optimize the steady state and dynamic behavior of low and high temperature fuel cells (PEMFC, DMFC, SOFC) to be applied in mobile and stationary systems. * Updates and informs the reader on the latest research findings using original reviews * Written by leading industry experts and scholars * Review

  2. Noise Characteristics of a Four-Jet Impingement Device Inside a Broadband Engine Noise Simulator

    Science.gov (United States)

    Brehm, Christoph; Housman, Jeffrey A.; Kiris, Cetin C.; Hutcheson, Florence V.

    2015-01-01

    The noise generation mechanisms for four directly impinging supersonic jets are investigated employing implicit large eddy simulations with a higher-order accurate weighted essentially non-oscillatory shock-capturing scheme. Impinging jet devices are often used as an experimental apparatus to emulate a broadband noise source. Although such devices have been used in many experiments, a detailed investigation of the noise generation mechanisms has not been conducted before. Thus, the underlying physical mechanisms that are responsible for the generation of sound waves are not well understood. The flow field is highly complex and contains a wide range of temporal and spatial scales relevant for noise generation. Proper orthogonal decomposition of the flow field is utilized to characterize the unsteady nature of the flow field involving unsteady shock oscillations, large coherent turbulent flow structures, and the sporadic appearance of vortex tubes in the center of the impingement region. The causality method based on Lighthill's acoustic analogy is applied to link fluctuations of flow quantities inside the source region to the acoustic pressure in the far field. It will be demonstrated that the entropy fluctuation term in the Lighthill's stress tensor plays a vital role in the noise generation process. Consequently, the understanding of the noise generation mechanisms is employed to develop a reduced-order linear acoustic model of the four-jet impingement device. Finally, three linear acoustic FJID models are used as broadband noise sources inside an engine nacelle and the acoustic scattering results are validated against far-field acoustic experimental data.

  3. Microscale technologies for cell engineering

    CERN Document Server

    Gaharwar, Akhilesh

    2016-01-01

    This book offers readers cutting-edge research at the interface of polymer science and engineering, biomedical engineering, materials science, and biology. State-of-the-art developments in microscale technologies for cell engineering applications are covered, including technologies relevant to both pluripotent and adult stem cells, the immune system, and somatic cells of the animal and human origin. This book bridges the gap in the understanding of engineering biology at multiple length scale, including microenvironmental control, bioprocessing, and tissue engineering in the areas of cardiac, cartilage, skeletal, and vascular tissues, among others. This book also discusses unique, emerging areas of micropatterning and three-dimensional printing models of cellular engineering, and contributes to the better understanding of the role of biophysical factors in determining the cell fate. Microscale Technologies for Cell Engineering is valuable for bioengineers, biomaterial scientists, tissue engineers, clinicians,...

  4. Intermediate Band Solar Cell with Extreme Broadband Spectrum Quantum Efficiency

    OpenAIRE

    2015-01-01

    We report, for the first time, about an intermediate band solar cell implemented with InAs/AlGaAs quantum dots whose photoresponse expands from 250 to ~ 6000  nm. To our knowledge, this is the broadest quantum efficiency reported to date for a solar cell and demonstrates that the intermediate band solar cell is capable of producing photocurrent when illuminated with photons whose energy equals the energy of the lowest band gap. We show experimental evidence indicating that this result is in a...

  5. Review Article: The weak interactive characteristic of resonance cells and broadband effect of metamaterials

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Xiaopeng, E-mail: xpzhao@nwpu.edu.cn; Song, Kun [Smart Materials Laboratory, Department of Applied Physics, Northwestern Polytechnical University, Xi’an, 710129 (China)

    2014-10-15

    Metamaterials are artificial media designed to control electromagnetic wave propagation. Due to resonance, most present-day metamaterials inevitably suffer from narrow bandwidth, extremely limiting their practical applications. On the basis of tailored properties, a metamaterial within which each distinct unit cell resonates at its inherent frequency and has almost no coupling effect with the other ones, termed as weak interaction system, can be formulated. The total response of a weak interaction system can be treated as an overlap of the single resonance spectrum of each type of different unit cells. This intriguing feature therefore makes it possible to accomplish multiband or broadband metamaterials in a simple way. By introducing defects into metamaterials to form a weak interaction system, multiband and broadband electromagnetic metamaterials have first been experimentally demonstrated by our group. The similar concept can also be readily extended to acoustic and seismic metamaterials.

  6. Review Article: The weak interactive characteristic of resonance cells and broadband effect of metamaterials

    Directory of Open Access Journals (Sweden)

    Xiaopeng Zhao

    2014-10-01

    Full Text Available Metamaterials are artificial media designed to control electromagnetic wave propagation. Due to resonance, most present-day metamaterials inevitably suffer from narrow bandwidth, extremely limiting their practical applications. On the basis of tailored properties, a metamaterial within which each distinct unit cell resonates at its inherent frequency and has almost no coupling effect with the other ones, termed as weak interaction system, can be formulated. The total response of a weak interaction system can be treated as an overlap of the single resonance spectrum of each type of different unit cells. This intriguing feature therefore makes it possible to accomplish multiband or broadband metamaterials in a simple way. By introducing defects into metamaterials to form a weak interaction system, multiband and broadband electromagnetic metamaterials have first been experimentally demonstrated by our group. The similar concept can also be readily extended to acoustic and seismic metamaterials.

  7. Review Article: The weak interactive characteristic of resonance cells and broadband effect of metamaterials

    International Nuclear Information System (INIS)

    Metamaterials are artificial media designed to control electromagnetic wave propagation. Due to resonance, most present-day metamaterials inevitably suffer from narrow bandwidth, extremely limiting their practical applications. On the basis of tailored properties, a metamaterial within which each distinct unit cell resonates at its inherent frequency and has almost no coupling effect with the other ones, termed as weak interaction system, can be formulated. The total response of a weak interaction system can be treated as an overlap of the single resonance spectrum of each type of different unit cells. This intriguing feature therefore makes it possible to accomplish multiband or broadband metamaterials in a simple way. By introducing defects into metamaterials to form a weak interaction system, multiband and broadband electromagnetic metamaterials have first been experimentally demonstrated by our group. The similar concept can also be readily extended to acoustic and seismic metamaterials

  8. Cell sheet engineering

    Directory of Open Access Journals (Sweden)

    Masayuki Yamato

    2004-05-01

    Full Text Available We have developed ‘cell sheet engineering’ in order to avoid the limitations of tissue reconstruction using biodegradable scaffolds or single cell suspension injection. Our concept is tissue reconstruction, not from single cells, but from cell sheets. Cell sheets are prepared using temperature-responsive culture dishes. Temperature-responsive polymers are covalently grafted onto the dishes, allowing various types of cells to adhere and proliferate at 37°C. The cells spontaneously detach when the temperature is reduced below 32°C without the need for proteolytic enzymes. The confluent cells are noninvasively harvested as single, contiguous cell sheets with intact cell-cell junctions and deposited extracellular matrix (ECM. We have used these harvested cell sheets for various tissue reconstructions, including ocular surfaces, periodontal ligaments, cardiac patches, and bladder augmentation.

  9. Dielectric nanostructures for broadband light trapping in organic solar cells

    KAUST Repository

    Raman, Aaswath

    2011-09-15

    Organic bulk heterojunction solar cells are a promising candidate for low-cost next-generation photovoltaic systems. However, carrier extraction limitations necessitate thin active layers that sacrifice absorption for internal quantum efficiency or vice versa. Motivated by recent theoretical developments, we show that dielectric wavelength-scale grating structures can produce significant absorption resonances in a realistic organic cell architecture. We numerically demonstrate that 1D, 2D and multi-level ITO-air gratings lying on top of the organic solar cell stack produce a 8-15% increase in photocurrent for a model organic solar cell where PCDTBT:PC71BM is the organic semiconductor. Specific to this approach, the active layer itself remains untouched yet receives the benefit of light trapping by nanostructuring the top surface below which it lies. The techniques developed here are broadly applicable to organic semiconductors in general, and enable partial decoupling between active layer thickness and photocurrent generation. © 2011 Optical Society of America.

  10. Graded index and randomly oriented core-shell silicon nanowires with broadband and wide angle antireflection for photovoltaic cell applications

    CERN Document Server

    Pignalosa, P; Qiao, L; Tseng, M; Yi, Yasha

    2011-01-01

    Antireflection with broadband and wide angle properties is important for a wide range of applications on photovoltaic cells and display. The SiOx shell layer provides a natural antireflection from air to the Si core absorption layer. In this work, we have demonstrated the random core-shell silicon nanowires with both broadband (from 400nm to 900nm) and wide angle (from normal incidence to 60\\degree) antireflection characteristics within AM1.5 solar spectrum. The graded index structure from the randomly oriented core-shell (Air/SiOx/Si) nanowires may provide a potential avenue to realize a broadband and wide angle antireflection layer.

  11. Nanopatterned front contact for broadband absorption in ultra-thin amorphous silicon solar cells

    OpenAIRE

    Massiot, I.; Colin, Clément; Péré-Laperne, Nicolas; Roca I Cabarrocas, Pere; Sauvan, Christophe; Lalanne, Philippe; Pelouard, Jean-Luc; Collin, Stéphane

    2012-01-01

    International audience Broadband light trapping is numerically demonstrated in ultra-thin solar cells composed of a flat amorphous silicon absorber layer deposited on a silver mirror. A one-dimensional silver array is used to enhance light absorption in the visible spectral range with low polarization and angle dependencies. In addition, the metallic nanowires play the role of transparent electrodes. We predict a short-circuit current density of 14:6mA=cm2 for a solar cell with a 90 nm-thi...

  12. Pluripotent Stem Cells for Schwann Cell Engineering

    NARCIS (Netherlands)

    Ma, Ming-San; Boddeke, Erik; Copray, Sjef

    2015-01-01

    Tissue engineering of Schwann cells (SCs) can serve a number of purposes, such as in vitro SC-related disease modeling, treatment of peripheral nerve diseases or peripheral nerve injury, and, potentially, treatment of CNS diseases. SCs can be generated from autologous stem cells in vitro by recapitu

  13. Kind of broad-band photonic valve and its application to silicon solar cells.

    Science.gov (United States)

    Le Perchec, J

    2012-09-10

    We investigate the dual optical behaviour of a photonic grating interface presenting a more or less important index contrast, showing either efficient broadband reflectivity, either high transmittance within the same spectral window, depending on the direction of the incident light. This behaviour is reminiscent of a diode one and could find interesting applications. A typical example is given for thin crystalline silicon solar cells where the rear side is directly nano-textured to trap light without metal reflector (bifacial device), well compatible with an integration in a photovoltaic module. PMID:23037524

  14. Cascading metallic gratings for broadband absorption enhancement in ultrathin plasmonic solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Wen, Long; Sun, Fuhe [Key Laboratory of Nanodevices and Applications-CAS and Collaborative Innovation Center of Suzhou Nano Science and Technology, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences (CAS), Suzhou 215123 (China); Chen, Qin, E-mail: qchen2012@sinano.ac.cn [Key Laboratory of Nanodevices and Applications-CAS and Collaborative Innovation Center of Suzhou Nano Science and Technology, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences (CAS), Suzhou 215123 (China); Peking University Shenzhen SOC Key Laboratory, PKU-HKUST Shenzhen-Hong Kong Institute, Hi-Tech Industrial Park South, Shenzhen 518057 (China)

    2014-04-14

    The incorporation of plasmonic nanostructures in the thin-film solar cells (TFSCs) is a promising route to harvest light into the nanoscale active layer. However, the light trapping scheme based on the plasmonic effects intrinsically presents narrow-band resonant enhancement of light absorption. Here we demonstrate that by cascading metal nanogratings with different sizes atop the TFSCs, broadband absorption enhancement can be realized by simultaneously exciting multiple localized surface plasmon resonances and inducing strong coupling between the plasmonic modes and photonic modes. As a proof of concept, we demonstrate of 66.5% in the photocurrent in an ultrathin amorphous silicon TFSC with two-dimensional cascaded gratings over the reference cell without gratings.

  15. Cascading metallic gratings for broadband absorption enhancement in ultrathin plasmonic solar cells

    International Nuclear Information System (INIS)

    The incorporation of plasmonic nanostructures in the thin-film solar cells (TFSCs) is a promising route to harvest light into the nanoscale active layer. However, the light trapping scheme based on the plasmonic effects intrinsically presents narrow-band resonant enhancement of light absorption. Here we demonstrate that by cascading metal nanogratings with different sizes atop the TFSCs, broadband absorption enhancement can be realized by simultaneously exciting multiple localized surface plasmon resonances and inducing strong coupling between the plasmonic modes and photonic modes. As a proof of concept, we demonstrate of 66.5% in the photocurrent in an ultrathin amorphous silicon TFSC with two-dimensional cascaded gratings over the reference cell without gratings

  16. THE DIRECT INFLUENCE OF THE CELL PERIMETER ON THE HANDOVER DELAY IN THE BROADBAND NETWORK

    Directory of Open Access Journals (Sweden)

    Elmabruk S M Elgembari

    2014-03-01

    Full Text Available One of the main keys of positioning and ranging technologies in wireless telecommunication networks is the values of distance and RSSI (Received Signal Strength Indication, side along with the cell perimeter have a significant relationship for the effect of the network quality in terms of quality in services and connectivity, and not less in the roaming stage. Many research results drove to influence these keys to the handover delay in the broadband network, so in many cases that MT handover between the boarders of location areas or zones has been affected by long time delay and packet data lost. Over recent years many signal propagation schemes have been presented to describe the relationship between cell size and Mobile terminal distance between the current and the targeted base station and RSSI. In this paper, the modify scheme of the location management area (LMA -based multimedia broadcast services scheme has been presented , the effect of cell size and distance between BS and MT and the RSSI , which shown their influence of the handoff delay . The analytical algorithm results showed the reduction of the handover delay in smaller perimeter cell size compared to the large cells in location management area.

  17. Engineering stem cell niches in bioreactors

    OpenAIRE

    2013-01-01

    Stem cells, including embryonic stem cells, induced pluripotent stem cells, mesenchymal stem cells and amniotic fluid stem cells have the potential to be expanded and differentiated into various cell types in the body. Efficient differentiation of stem cells with the desired tissue-specific function is critical for stem cell-based cell therapy, tissue engineering, drug discovery and disease modeling. Bioreactors provide a great platform to regulate the stem cell microenvironment, known as “ni...

  18. A Bottom-Up Engineered Broadband Optical Nanoabsorber for Radiometry and Energy Harnessing Applications

    Science.gov (United States)

    Kaul, Anupama B.; Coles, James B.; Megerian, Krikor G.; Eastwood, Michael; Green, Robert O.; Bandaru, Prabhakar R.

    2013-01-01

    Optical absorbers based on vertically aligned multi-walled carbon nanotubes (MWCNTs), synthesized using electric-field assisted growth, are described here that show an ultra-low reflectance, 100X lower compared to Au-black from wavelength lamba approximately 350 nm - 2.5 micron. A bi-metallic Co/Ti layer was shown to catalyze a high site density of MWCNTs on metallic substrates and the optical properties of the absorbers were engineered by controlling the bottom-up synthesis conditions using dc plasma-enhanced chemical vapor deposition (PECVD). Reflectance measurements on the MWCNT absorbers after heating them in air to 400deg showed negligible changes in reflectance which was still low, approximately 0.022 % at lamba approximately 2 micron. In contrast, the percolated structure of the reference Au-black samples collapsed completely after heating, causing the optical response to degrade at temperatures as low as 200deg. The high optical absorption efficiency of the MWCNT absorbers, synthesized on metallic substrates, over a broad spectral range, coupled with their thermal ruggedness, suggests they have promise in solar energy harnessing applications, as well as thermal detectors for radiometry.

  19. Aggregates of plasmonic nanoparticles for broadband light trapping in dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Metallic nanoparticles (NPs) have not been effective in improving the overall performance of the cells with micrometer-thick absorbing layers mainly due to the parasitic optical dissipation in the metal. Here, using both experiment and theory, we demonstrate that aggregates of metallic NPs enhance the light absorption of dye-sensitized solar cells of a few micrometer-thick light absorbing layers. The composite electrode containing the optimal concentration of 5 wt% Au@SiO2 aggregates shows the enhancement of 80% and 52% in external quantum efficiency and photocurrent density, respectively. The superior performance of the aggregates relative to NP is attributed to their larger scattering efficiency using full-wave optical simulations. This is further confirmed by optical spectroscopic measurements showing that a large fraction of the incident light couples into the diffused components because of the presence of these metallic aggregates. The optical absorption enhancement is broadband and it is particularly strong at wavelengths larger than 680 nm where the optical absorption of dye molecules is weak. (paper)

  20. Broadband light absorption enhancement in dye-sensitized solar cells with Au-Ag alloy popcorn nanoparticles

    OpenAIRE

    Qi Xu; Fang Liu; Yuxiang Liu; Kaiyu Cui; Xue Feng; , Wei Zhang; Yidong Huang

    2013-01-01

    In this paper, we present an investigation on the use of Au-Ag alloy popcorn-shaped nanoparticles (NPs) to realise the broadband optical absorption enhancement of dye-sensitized solar cells (DSCs). Both simulation and experimental results indicate that compared with regular plasmonic NPs, such as nano-spheres, irregular popcorn-shaped alloy NPs exhibit absorption enhancement over a broad wavelength range due to the excitation of localized surface plasmons (LSPs) at different wavelengths. The ...

  1. Czech way to broadband

    Czech Academy of Sciences Publication Activity Database

    Kuchar, Anton; Peterka, J.; Hrstka, J.; Hankiewiczová, H.

    -, August (2006), s. 274-278. ISSN 1106-2975. [FITCE Congress /45./. Athens, 30.08.2006-02.09.2006] Grant ostatní: BReATH Consortium EU(XE) EC FP6 1ST Programme Institutional research plan: CEZ:AV0Z20670512 Keywords : telecommunication networks * Internet * broadband networks Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  2. Mesenchymal Stem Cells and Tooth Engineering

    Institute of Scientific and Technical Information of China (English)

    Li Peng; Ling Ye; Xue-dong Zhou

    2009-01-01

    Tooth loss compromises human oral health. Although several prosthetic methods, such as artificial denture and dental implants, are clinical therapies to tooth loss problems, they are thought to have safety and usage time issues. Recently, tooth tissue engineering has attracted more and more attention. Stem cell based tissue engineering is thought to be a promising way to replace the missing tooth. Mesenchymal stem cells (MSCs) are multipotent stem cells which can differentiate into a variety of cell types. The potential MSCs for tooth regeneration mainly include stem cells from human exfoliated deciduous teeth (SHEDs), adult dental pulp stem cells (DPSCs), stem cells from the apical part of the papilla (SCAPs), stem cells from the dental follicle (DFSCs), periodontal ligament stem cells (PDLSCs) and bone marrow derived mesenchymal stem cells (BMSCs). This review outlines the recent progress in the mesenchymal stem cells used in tooth regeneration.

  3. Stem cells in bone tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Seong, Jeong Min [Department of Preventive and Social Dentistry and Institute of Oral Biology, College of Dentistry, Kyung Hee University, Seoul 130-701 (Korea, Republic of); Kim, Byung-Chul; Park, Jae-Hong; Kwon, Il Keun; Hwang, Yu-Shik [Department of Maxillofacial Biomedical Engineering and Institute of Oral Biology, College of Dentistry, Kyung Hee University, Seoul 130-701 (Korea, Republic of); Mantalaris, Anathathios, E-mail: yshwang@khu.ac.k [Department of Chemical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ (United Kingdom)

    2010-12-15

    Bone tissue engineering has been one of the most promising areas of research, providing a potential clinical application to cure bone defects. Recently, various stem cells including embryonic stem cells (ESCs), bone marrow-derived mesenchymal stem cells (BM-MSCs), umbilical cord blood-derived mesenchymal stem cells (UCB-MSCs), adipose tissue-derived stem cells (ADSCs), muscle-derived stem cells (MDSCs) and dental pulp stem cells (DPSCs) have received extensive attention in the field of bone tissue engineering due to their distinct biological capability to differentiate into osteogenic lineages. The application of these stem cells to bone tissue engineering requires inducing in vitro differentiation of these cells into bone forming cells, osteoblasts. For this purpose, efficient in vitro differentiation towards osteogenic lineage requires the development of well-defined and proficient protocols. This would reduce the likelihood of spontaneous differentiation into divergent lineages and increase the available cell source for application to bone tissue engineering therapies. This review provides a critical examination of the various experimental strategies that could be used to direct the differentiation of ESC, BM-MSC, UCB-MSC, ADSC, MDSC and DPSC towards osteogenic lineages and their potential applications in tissue engineering, particularly in the regeneration of bone. (topical review)

  4. Stem cells in bone tissue engineering

    International Nuclear Information System (INIS)

    Bone tissue engineering has been one of the most promising areas of research, providing a potential clinical application to cure bone defects. Recently, various stem cells including embryonic stem cells (ESCs), bone marrow-derived mesenchymal stem cells (BM-MSCs), umbilical cord blood-derived mesenchymal stem cells (UCB-MSCs), adipose tissue-derived stem cells (ADSCs), muscle-derived stem cells (MDSCs) and dental pulp stem cells (DPSCs) have received extensive attention in the field of bone tissue engineering due to their distinct biological capability to differentiate into osteogenic lineages. The application of these stem cells to bone tissue engineering requires inducing in vitro differentiation of these cells into bone forming cells, osteoblasts. For this purpose, efficient in vitro differentiation towards osteogenic lineage requires the development of well-defined and proficient protocols. This would reduce the likelihood of spontaneous differentiation into divergent lineages and increase the available cell source for application to bone tissue engineering therapies. This review provides a critical examination of the various experimental strategies that could be used to direct the differentiation of ESC, BM-MSC, UCB-MSC, ADSC, MDSC and DPSC towards osteogenic lineages and their potential applications in tissue engineering, particularly in the regeneration of bone. (topical review)

  5. Stem cell engineering a WTEC global assessment

    CERN Document Server

    Loring, Jeanne; McDevitt, Todd; Palecek, Sean; Schaffer, David; Zandstra, Peter

    2014-01-01

    This book describes a global assessment of stem cell engineering research, achieved through site visits by a panel of experts to leading institutes, followed by dedicated workshops. The assessment made clear that engineers and the engineering approach with its quantitative, system-based thinking can contribute much to the progress of stem cell research and development. The increased need for complex computational models and new, innovative technologies, such as high-throughput screening techniques, organ-on-a-chip models and in vitro tumor models require an increasing involvement of engineers and physical scientists. Additionally, this book will show that although the US is still in a leadership position in stem cell engineering, Asian countries such as Japan, China and Korea, as well as European countries like the UK, Germany, Sweden and the Netherlands are rapidly expanding their investments in the field. Strategic partnerships between countries could lead to major advances of the field and scalable expansi...

  6. Simulation Model Driven Engineering for Manufacturing Cell

    OpenAIRE

    Hibino, Hironori; Inukai, Toshihiro; Yoshida, Yukishige

    2010-01-01

    In our research, the simulation model driven engineering for manufacturing cell (SMDE-MC) is proposed. The purposes of SMDE-MC are to support the manufacturing engineering processes based on the simulation model and to extend the range of control applications and simulation applications using the PC based control. SMDE-MC provides the simulation model which controls and monitors the manufacturing cell directly using PC based control in the manufacturing system execution phase. Then when the s...

  7. Broadband anti-reflective and water-repellent coatings on glass substrates for self-cleaning photovoltaic cells

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xiaoyu [Functional Nanomaterials Laboratory and Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry (TIPC), Chinese Academy of Sciences, Zhongguancun Donglu 29, Haidianqu, Beijing 100190 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); He, Junhui, E-mail: jhhe@mail.ipc.ac.cn [Functional Nanomaterials Laboratory and Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry (TIPC), Chinese Academy of Sciences, Zhongguancun Donglu 29, Haidianqu, Beijing 100190 (China); Liu, Weiyi [Institute of Optoelectronics, Nankai University, Tianjin 300071 (China)

    2013-07-15

    Graphical abstract: High performance broadband antireflective and water-repellent coatings were fabricated on glass substrates, which can improve the short-circuit current of solar cells as much as 6.6% in comparison with glass substrates without the coatings. - Highlights: • Broadband anti-reflective and water-repellent coatings were fabricated. • Transmittance increased to 99.0%, significantly higher than that of commercial solar glasses. • The performance of standard solar cells with the AR coating was enhanced as much as 6.6%. - Abstract: High performance broadband antireflective (AR) and water-repellent coatings were fabricated on glass substrates by assembly of silica nanoparticles and polyelectrolytes via the layer-by-layer (LbL) assembly technique, followed by calcination and hydrophobic modification. A porous poly(diallyladimethylammonium chloride) (PDDA)/20 nm SiO{sub 2} nanoparticles (S-20) multilayer coating with AR property was prepared first. The maximum transmittance is as high as 99.0%, while that of the glass substrate is only 91.3%. After calcination and hydrophobic modification, the coating became water-repellent while maintaining the good AR property. Such water-repellent AR coatings can improve the short-circuit current of solar cells as much as 6.6% in comparison with glass substrates without the coatings. Scanning electron microscopy (SEM) was used to observe the morphology and thickness of coatings. Transmission spectra and reflection spectra were characterized by UV–vis spectrophotometer. The surface wettability was studied by a contact angle/interface system.

  8. Broadband anti-reflective and water-repellent coatings on glass substrates for self-cleaning photovoltaic cells

    International Nuclear Information System (INIS)

    Graphical abstract: High performance broadband antireflective and water-repellent coatings were fabricated on glass substrates, which can improve the short-circuit current of solar cells as much as 6.6% in comparison with glass substrates without the coatings. - Highlights: • Broadband anti-reflective and water-repellent coatings were fabricated. • Transmittance increased to 99.0%, significantly higher than that of commercial solar glasses. • The performance of standard solar cells with the AR coating was enhanced as much as 6.6%. - Abstract: High performance broadband antireflective (AR) and water-repellent coatings were fabricated on glass substrates by assembly of silica nanoparticles and polyelectrolytes via the layer-by-layer (LbL) assembly technique, followed by calcination and hydrophobic modification. A porous poly(diallyladimethylammonium chloride) (PDDA)/20 nm SiO2 nanoparticles (S-20) multilayer coating with AR property was prepared first. The maximum transmittance is as high as 99.0%, while that of the glass substrate is only 91.3%. After calcination and hydrophobic modification, the coating became water-repellent while maintaining the good AR property. Such water-repellent AR coatings can improve the short-circuit current of solar cells as much as 6.6% in comparison with glass substrates without the coatings. Scanning electron microscopy (SEM) was used to observe the morphology and thickness of coatings. Transmission spectra and reflection spectra were characterized by UV–vis spectrophotometer. The surface wettability was studied by a contact angle/interface system

  9. Stem Cells and Tissue Engineering

    CERN Document Server

    Pavlovic, Mirjana

    2013-01-01

    Stem cells are the building blocks for all other cells in an organism. The human body has about 200 different types of cells and any of those cells can be produced by a stem cell. This fact emphasizes the significance of stem cells in transplantational medicine, regenerative therapy and bioengineering. Whether embryonic or adult, these cells can be used for the successful treatment of a wide range of diseases that were not treatable before, such as osteogenesis imperfecta in children, different forms of leukemias, acute myocardial infarction, some neural damages and diseases, etc. Bioengineering, e.g. successful manipulation of these cells with multipotential capacity of differentiation toward appropriate patterns and precise quantity, are the prerequisites for successful outcome and treatment. By combining in vivo and in vitro techniques, it is now possible to manage the wide spectrum of tissue damages and organ diseases. Although the stem-cell therapy is not a response to all the questions, it provides more...

  10. Application of Stem Cells in Tissue Engineering

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Stem cells have become an important source of seed cells for tissue engineering because they are relatively easy to expand in vitro and can be induced to differentiate into various cell types in vitro or in vivo. In the current stage, most stem cell researches focus on in vitro studies, including in vitro induction and phenotype characterization. Our center has made a great deal of effort in the in vivo study by using stem cells as seed cells for tissue construction. We have used bone marrow stem cells (BMS...

  11. Cancer Immunotherapy Using Engineered Hematopoietic Stem Cells

    OpenAIRE

    Gschweng, Eric Hans

    2015-01-01

    Engineering the immune system against cancer ideally provides surgical precision against the antigen bearing target cell while avoiding the systemic, off-target toxicity of chemotherapy. Successful treatment of patients in the clinic has been achieved by the expression of anti-cancer T-cell receptors (TCR) and chimeric antigen receptors (CAR) in T cells followed by infusion of these cells into cancer patients. Unfortunately, while many patients initially respond showing anti-tumor efficacy, t...

  12. Glycan Engineering for Cell and Developmental Biology

    Science.gov (United States)

    Griffin, Matthew E.; Hsieh-Wilson, Linda C.

    2016-01-01

    Cell-surface glycans are a diverse class of macromolecules that participate in many key biological processes, including cell-cell communication, development, and disease progression. Thus, the ability to modulate the structures of glycans on cell surfaces provides a powerful means not only to understand fundamental processes but also to direct activity and elicit desired cellular responses. Here, we describe methods to sculpt glycans on cell surfaces and highlight recent successes in which artificially engineered glycans have been employed to control biological outcomes such as the immune response and stem cell fate. PMID:26933739

  13. Engineering the Polyketide Cell Factory

    DEFF Research Database (Denmark)

    Mølgaard, Louise

    Natural products constitute one of the largest sources of therapeutics known to mankind. Among the natural products polyketides such as erythromycin (antibiotic) and lovastatin (cholesterol lowering) have long proven their immense value to patients around the world. Polyketides are naturally...... through the use of adaptive evolution, random mutagenesis and screening as well as metabolic engineering. Firstly, in silico guided metabolic engineering was used as a tool to direct metabolism towards higher levels of 6-MSA production in A. nidulans. 6-MSA was stably expressed in the A. nidulans genome...... platform can be used for both process optimization as well as screening libraries of mutants generated through random mutagenesis. The experiments validated the CDD-flatbed scanning platform as a tool for quantifying microbial biomass from both bacteria and yeasts. Furthermore, the platform can be used to...

  14. Engineered cell-cell communication via DNA messaging

    Directory of Open Access Journals (Sweden)

    Ortiz Monica E

    2012-09-01

    Full Text Available Abstract Background Evolution has selected for organisms that benefit from genetically encoded cell-cell communication. Engineers have begun to repurpose elements of natural communication systems to realize programmed pattern formation and coordinate other population-level behaviors. However, existing engineered systems rely on system-specific small molecules to send molecular messages among cells. Thus, the information transmission capacity of current engineered biological communication systems is physically limited by specific biomolecules that are capable of sending only a single message, typically “regulate transcription.” Results We have engineered a cell-cell communication platform using bacteriophage M13 gene products to autonomously package and deliver heterologous DNA messages of varying lengths and encoded functions. We demonstrate the decoupling of messages from a common communication channel via the autonomous transmission of various arbitrary genetic messages. Further, we increase the range of engineered DNA messaging across semisolid media by linking message transmission or receipt to active cellular chemotaxis. Conclusions We demonstrate decoupling of a communication channel from message transmission within engineered biological systems via the autonomous targeted transduction of user-specified heterologous DNA messages. We also demonstrate that bacteriophage M13 particle production and message transduction occurs among chemotactic bacteria. We use chemotaxis to improve the range of DNA messaging, increasing both transmission distance and communication bit rates relative to existing small molecule-based communication systems. We postulate that integration of different engineered cell-cell communication platforms will allow for more complex spatial programming of dynamic cellular consortia.

  15. RAxML-Cell: Parallel Phylogenetic Tree Inference on the Cell Broadband Engine

    OpenAIRE

    Blagojevic, Filip; Stamatakis, Alexandros; Antonopoulos, Christos; Nikolopoulos, Dimitrios

    2006-01-01

    Phylogenetic tree reconstruction is one of the grand challenge problems in Bioinformatics. The search for a best-scoring tree with 50 organisms, under a reasonable optimality criterion, creates a topological search space which is as large as the number of atoms in the universe. Computational phylogeny is challenging even for the most powerful supercomputers. It is also an ideal candidate for benchmarking emerging multiprocessor architectures, because it exhibits various l...

  16. Engineering Hematopoietic Stem Cells: Lessons from Development.

    Science.gov (United States)

    Rowe, R Grant; Mandelbaum, Joseph; Zon, Leonard I; Daley, George Q

    2016-06-01

    Cell engineering has brought us tantalizingly close to the goal of deriving patient-specific hematopoietic stem cells (HSCs). While directed differentiation and transcription factor-mediated conversion strategies have generated progenitor cells with multilineage potential, to date, therapy-grade engineered HSCs remain elusive due to insufficient long-term self-renewal and inadequate differentiated progeny functionality. A cross-species approach involving zebrafish and mammalian systems offers complementary methodologies to improve understanding of native HSCs. Here, we discuss the role of conserved developmental timing processes in vertebrate hematopoiesis, highlighting how identification and manipulation of stage-specific factors that specify HSC developmental state must be harnessed to engineer HSCs for therapy. PMID:27257760

  17. Fuel-cell engine stream conditioning system

    Science.gov (United States)

    DuBose, Ronald Arthur

    2002-01-01

    A stream conditioning system for a fuel cell gas management system or fuel cell engine. The stream conditioning system manages species potential in at least one fuel cell reactant stream. A species transfer device is located in the path of at least one reactant stream of a fuel cell's inlet or outlet, which transfer device conditions that stream to improve the efficiency of the fuel cell. The species transfer device incorporates an exchange media and a sorbent. The fuel cell gas management system can include a cathode loop with the stream conditioning system transferring latent and sensible heat from an exhaust stream to the cathode inlet stream of the fuel cell; an anode humidity retention system for maintaining the total enthalpy of the anode stream exiting the fuel cell related to the total enthalpy of the anode inlet stream; and a cooling water management system having segregated deionized water and cooling water loops interconnected by means of a brazed plate heat exchanger.

  18. Computational adaptive optics for broadband interferometric tomography of tissues and cells

    Science.gov (United States)

    Adie, Steven G.; Mulligan, Jeffrey A.

    2016-03-01

    Adaptive optics (AO) can shape aberrated optical wavefronts to physically restore the constructive interference needed for high-resolution imaging. With access to the complex optical field, however, many functions of optical hardware can be achieved computationally, including focusing and the compensation of optical aberrations to restore the constructive interference required for diffraction-limited imaging performance. Holography, which employs interferometric detection of the complex optical field, was developed based on this connection between hardware and computational image formation, although this link has only recently been exploited for 3D tomographic imaging in scattering biological tissues. This talk will present the underlying imaging science behind computational image formation with optical coherence tomography (OCT) -- a beam-scanned version of broadband digital holography. Analogous to hardware AO (HAO), we demonstrate computational adaptive optics (CAO) and optimization of the computed pupil correction in 'sensorless mode' (Zernike polynomial corrections with feedback from image metrics) or with the use of 'guide-stars' in the sample. We discuss the concept of an 'isotomic volume' as the volumetric extension of the 'isoplanatic patch' introduced in astronomical AO. Recent CAO results and ongoing work is highlighted to point to the potential biomedical impact of computed broadband interferometric tomography. We also discuss the advantages and disadvantages of HAO vs. CAO for the effective shaping of optical wavefronts, and highlight opportunities for hybrid approaches that synergistically combine the unique advantages of hardware and computational methods for rapid volumetric tomography with cellular resolution.

  19. Engineered Models of Confined Cell Migration.

    Science.gov (United States)

    Paul, Colin D; Hung, Wei-Chien; Wirtz, Denis; Konstantopoulos, Konstantinos

    2016-07-11

    Cells in the body are physically confined by neighboring cells, tissues, and the extracellular matrix. Although physical confinement modulates intracellular signaling and the underlying mechanisms of cell migration, it is difficult to study in vivo. Furthermore, traditional two-dimensional cell migration assays do not recapitulate the complex topographies found in the body. Therefore, a number of experimental in vitro models that confine and impose forces on cells in well-defined microenvironments have been engineered. We describe the design and use of microfluidic microchannel devices, grooved substrates, micropatterned lines, vertical confinement devices, patterned hydrogels, and micropipette aspiration assays for studying cell responses to confinement. Use of these devices has enabled the delineation of changes in cytoskeletal reorganization, cell-substrate adhesions, intracellular signaling, nuclear shape, and gene expression that result from physical confinement. These assays and the physiologically relevant signaling pathways that have been elucidated are beginning to have a translational and clinical impact. PMID:27420571

  20. Broadband light absorption enhancement in dye-sensitized solar cells with Au-Ag alloy popcorn nanoparticles

    Science.gov (United States)

    Xu, Qi; Liu, Fang; Liu, Yuxiang; Cui, Kaiyu; Feng, Xue; Zhang, Wei; Huang, Yidong

    2013-07-01

    In this paper, we present an investigation on the use of Au-Ag alloy popcorn-shaped nanoparticles (NPs) to realise the broadband optical absorption enhancement of dye-sensitized solar cells (DSCs). Both simulation and experimental results indicate that compared with regular plasmonic NPs, such as nano-spheres, irregular popcorn-shaped alloy NPs exhibit absorption enhancement over a broad wavelength range due to the excitation of localized surface plasmons (LSPs) at different wavelengths. The power conversion efficiency (PCE) of DSCs is enhanced by 16% from 5.26% to 6.09% by incorporating 2.38 wt% Au-Ag alloy popcorn NPs. Moreover, by adding a scattering layer on the exterior of the counter electrode, the popcorn NPs demonstrate an even stronger ability to increase the PCE by 32% from 5.94% to 7.85%, which results from the more efficient excitation of the LSP mode on the popcorn NPs.

  1. Simultaneous broadband light trapping and fill factor enhancement in crystalline silicon solar cells induced by Ag nanoparticles and nanoshells.

    Science.gov (United States)

    Fahim, Narges F; Jia, Baohua; Shi, Zhengrong; Gu, Min

    2012-09-10

    Crystalline silicon solar cells are predominant and occupying more than 89% of the global solar photovoltaic market. Despite the boom of the innovative solar technologies, few can provide a low-cost radical solution to dramatically boost the efficiency of crystalline silicon solar cells, which has reached plateau in the past ten years. Here, we present a novel strategy to simultaneously achieve dramatic enhancement in the short-circuit current and the fill factor through the integration of Ag plasmonic nanoparticles and nanoshells on the antireflection coating and the screen-printed fingers of monocrystalline silicon solar cells, respectively, by a single step and scalable modified electroless displacement method. As a consequence, up to 35.2% enhancement in the energy conversion efficiency has been achieved due to the plasmonic broadband light trapping and the significant reduction in the series resistance. More importantly, this method can further increase the efficiency of the best performing textured solar cells from 18.3% to 19.2%, producing the highest efficiency cells exceeding the state-of-the-art efficiency of the standard screen-printed solar cells. The dual functions of the Ag nanostructures, reported for the first time here, present a clear contrast to the previous works, where plasmonic nanostructures were integrated into solar cells to achieve the short-circuit current enhancement predominately. Our method offers a facile, cost-effective and scalable pathway for metallic nanostructures to be used to dramatically boost the overall efficiency of the optically thick crystalline silicon solar cells. PMID:23037536

  2. Cell-Free Metabolic Engineering: Biomanufacturing beyond the cell

    OpenAIRE

    Dudley, Quentin M.; Karim, Ashty S.; Jewett, Michael C.

    2014-01-01

    Industrial biotechnology and microbial metabolic engineering are poised to help meet the growing demand for sustainable, low-cost commodity chemicals and natural products, yet the fraction of biochemicals amenable to commercial production remains limited. Common problems afflicting the current state-of-the-art include low volumetric productivities, build-up of toxic intermediates or products, and byproduct losses via competing pathways. To overcome these limitations, cell-free metabolic engin...

  3. TOPICAL REVIEW: Stem cells engineering for cell-based therapy

    Science.gov (United States)

    Taupin, Philippe

    2007-09-01

    Stem cells carry the promise to cure a broad range of diseases and injuries, from diabetes, heart and muscular diseases, to neurological diseases, disorders and injuries. Significant progresses have been made in stem cell research over the past decade; the derivation of embryonic stem cells (ESCs) from human tissues, the development of cloning technology by somatic cell nuclear transfer (SCNT) and the confirmation that neurogenesis occurs in the adult mammalian brain and that neural stem cells (NSCs) reside in the adult central nervous system (CNS), including that of humans. Despite these advances, there may be decades before stem cell research will translate into therapy. Stem cell research is also subject to ethical and political debates, controversies and legislation, which slow its progress. Cell engineering has proven successful in bringing genetic research to therapy. In this review, I will review, in two examples, how investigators are applying cell engineering to stem cell biology to circumvent stem cells' ethical and political constraints and bolster stem cell research and therapy.

  4. Broadband omnidirectional antireflection coatings for metal-backed solar cells optimized using simulated annealing algorithm incorporated with solar spectrum.

    Science.gov (United States)

    Chang, Yin-Jung; Chen, Yu-Ting

    2011-07-01

    Broadband omnidirectional antireflection (AR) coatings for solar cells optimized using simulated annealing (SA) algorithm incorporated with the solar (irradiance) spectrum at Earth's surface (AM1.57 radiation) are described. Material dispersions and reflections from the planar backside metal are considered in the rigorous electromagnetic calculations. Optimized AR coatings for bulk crystalline Si and thin-film CuIn(1-x)GaxSe(2) (CIGS) solar cells as two representative cases are presented and the effect of solar spectrum in the AR coating designs is investigated. In general, the angle-averaged reflectance of a solar-spectrum-incorporated AR design is shown to be smaller and more uniform in the spectral range with relatively stronger solar irradiance. By incorporating the transparent conductive and buffer layers as part of the AR coating in CIGS solar cells (2μm-thick CIGS layer), a single MgF(2) layer could provide an average reflectance of 8.46% for wavelengths ranging from 350 nm to 1200 nm and incident angles from 0° to 80°. PMID:21747557

  5. Metasurface Broadband Solar Absorber

    OpenAIRE

    Azad, Abul K.; Kort-Kamp, Wilton J. M.; Milan Sykora; Nina R. Weisse-Bernstein; Luk, Ting S.; Antoinette J. Taylor; Dalvit, Diego A. R.; Hou-Tong Chen

    2016-01-01

    We demonstrate a broadband, polarization independent, omnidirectional absorber based on a metallic metasurface architecture, which accomplishes greater than 90% absorptance in the visible and near-infrared range of the solar spectrum, and exhibits low emissivity at mid- and far-infrared wavelengths. The complex unit cell of the metasurface solar absorber consists of eight pairs of gold nano-resonators that are separated from a gold ground plane by a thin silicon dioxide spacer. Our experiment...

  6. Broadband perfect light trapping in the thinnest monolayer graphene-MoS$_{2}$ photovoltaic cell

    CERN Document Server

    Wu, Yun-Beng; Wang, Tong-Biao; Deng, Xin-Hua; Liu, Jiang-Tao

    2015-01-01

    The light absorption of a monolayer graphene-molybdenum disulfide photovoltaic (GM-PV) cell in a wedge-shaped microcavity with a spectrum-splitting structure is investigated theoretically. The GM-PV cell, which is three times thinner than the traditional photovoltaic cell, exhibits up to 98\\% light absorptivity in a wide wavelength range. This rate exceeds the fundamental limit of nanophotonic light trapping in solar cells. The effects of defect layer thickness, GM-PV cell position in the microcavity, incident angle, and lens aberration on the light absorption rate of the GM-PV cell is explored. Regardless of errors, the GM-PV cell can still achieve at least 90\\% light absorptivity with the current technology. Our proposal provides different methods to design light-trapping structures and apply spectrum-splitting systems.

  7. Cell-free metabolic engineering: Biomanufacturing beyond the cell

    Energy Technology Data Exchange (ETDEWEB)

    Dudley, QM; Karim, AS; Jewett, MC

    2014-10-15

    Industrial biotechnology and microbial metabolic engineering are poised to help meet the growing demand for sustainable, low-cost commodity chemicals and natural products, yet the fraction of biochemicals amenable to commercial production remains limited. Common problems afflicting the current state-of-the-art include low volumetric productivities, build-up of toxic intermediates or products, and byproduct losses via competing pathways. To overcome these limitations, cell-free metabolic engineering (CFME) is expanding the scope of the traditional bioengineering model by using in vitro ensembles of catalytic proteins prepared from purified enzymes or crude lysates of cells for the production of target products. In recent years, the unprecedented level of control and freedom of design, relative to in vivo systems, has inspired the development of engineering foundations for cell-free systems. These efforts have led to activation of long enzymatic pathways (>8 enzymes), near theoretical conversion yields, productivities greater than 100 mg L-1 h(-1), reaction scales of >100 L, and new directions in protein purification, spatial organization, and enzyme stability. In the coming years, CFME will offer exciting opportunities to: (i) debug and optimize biosynthetic pathways; (ii) carry out design-build-test iterations without re-engineering organisms; and (iii) perform molecular transformations when bioconversion yields, productivities, or cellular toxicity limit commercial feasibility.

  8. Broadband photocurrent enhancement and light-trapping in thin film Si solar cells with periodic Al nanoparticle arrays on the front.

    Science.gov (United States)

    Uhrenfeldt, C; Villesen, T F; Têtu, A; Johansen, B; Larsen, A Nylandsted

    2015-06-01

    Plasmonic resonances in metal nanoparticles are considered candidates for improved thin film Si photovoltaics. In periodic arrays the influence of collective modes can enhance the resonant properties of such arrays. We have investigated the use of periodic arrays of Al nanoparticles placed on the front of a thin film Si test solar cell. It is demonstrated that the resonances from the Al nanoparticle array causes a broadband photocurrent enhancement ranging from the ultraviolet to the infrared with respect to a reference cell. From the experimental results as well as from numerical simulations it is shown that this broadband enhancement is due to single particle resonances that give rise to light-trapping in the infrared spectral range and to collective resonances that ensure an efficient in-coupling of light in the ultraviolet-blue spectral range. PMID:26072877

  9. Engineering CAR-T Cells: Design Concepts

    Science.gov (United States)

    Srivastava, Shivani; Riddell, Stanley R.

    2016-01-01

    Despite being empirically designed based on a simple understanding of TCR signaling, T cells engineered with chimeric antigen receptors (CARs) have been remarkably successful in treating patients with advanced refractory B cell malignancies. However, many challenges remain in improving the safety and efficacy of this therapy and extending it toward the treatment of epithelial cancers. Other aspects TCR signaling beyond those directly provided by CD3ζ and CD28 phosphorylation strongly influence a T cell’s ability to differentiate and acquire full effector functions. Here, we discuss how the principles of TCR recognition, including spatial constraints, Kon/Koff rates, and synapse formation, along with in-depth analysis of CAR signaling might be applied to develop safer and more effective synthetic tumor targeting receptors. PMID:26169254

  10. Broadband and omnidirectional anti-reflection layer for III/V multi-junction solar cells

    CERN Document Server

    Diedenhofen, Silke L; Haverkamp, Erik; Bauhuis, Gerard; Schermer, John; Rivas, Jaime Gómez; 10.1016/j.solmat.2012.02.022

    2012-01-01

    We report a novel graded refractive index antireflection coating for III/V quadruple solar cells based on bottom-up grown tapered GaP nanowires. We have calculated the photocurrent density of an InGaP-GaAs-InGaAsP-InGaAs solar cell with a MgF2/ZnS double layer antireflection coating and with a graded refractive index coating. The photocurrent density can be increased by 5.9 % when the solar cell is coated with a graded refractive index layer with a thickness of 1\\mu m. We propose to realize such a graded refractive index layer by growing tapered GaP nanowires on III/V solar cells. For a first demonstration of the feasibility of the growth of tapered nanowires on III/V solar cells, we have grown tapered GaP nanowires on AlInP/GaAs substrates. We show experimentally that the reflection from the nanowire coated substrate is reduced and that the transmission into the substrate is increased for a broad spectral and angular range.

  11. High efficiency, broadband solar cell architectures based on arrays of volumetrically distributed narrowband photovoltaic fibers.

    Science.gov (United States)

    O'Connor, Brendan; Nothern, Denis; Pipe, Kevin P; Shtein, Max

    2010-09-13

    We propose a novel solar cell architecture consisting of multiple fiber-based photovoltaic (PV) cells. Each PV fiber element is designed to maximize the power conversion efficiency within a narrow band of the incident solar spectrum, while reflecting other spectral components through the use of optical microcavity effects and distributed Bragg reflector (DBR) coatings. Combining PV fibers with complementary absorption and reflection characteristics into volume-filling arrays enables spectrally tuned modules having an effective dispersion element intrinsic to the architecture, resulting in high external quantum efficiency over the incident spectrum. While this new reflective tandem architecture is not limited to one particular material system, here we apply the concept to organic PV (OPV) cells that use a metal-organic-metal-dielectric layer structure, and calculate the expected performance of such arrays. Using realistic material properties for organic absorbers, transport layers, metallic electrodes, and DBR coatings, 17% power conversion efficiency can be reached. PMID:21165073

  12. Broadband Absorption Enhancement in Thin Film Solar Cells Using Asymmetric Double-Sided Pyramid Gratings

    Science.gov (United States)

    Alshal, Mohamed A.; Allam, Nageh K.

    2016-07-01

    A design for a highly efficient modified grating crystalline silicon (c-Si) thin film solar cell is demonstrated and analyzed using the two-dimensional (2-D) finite element method. The suggested grating has a double-sided pyramidal structure. The incorporation of the modified grating in a c-Si thin film solar cell offers a promising route to harvest light into the few micrometers active layer. Furthermore, a layer of silicon nitride is used as an antireflection coating (ARC). Additionally, the light trapping through the suggested design is significantly enhanced by the asymmetry of the top and bottom pyramids. The effects of the thickness of the active layer and facet angle of the pyramid on the spectral absorption, ultimate efficiency (η), and short-circuit current density (J sc) are investigated. The numerical results showed 87.9% efficiency improvement over the conventional thin film c-Si solar cell counterpart without gratings.

  13. Reconstruction of Computerized Tomography Images on a Cell Broadband Engine using Ray based Interpolation

    DEFF Research Database (Denmark)

    Jørgensen, M. E.; Vinter, Brian

    2009-01-01

    on an Intel Core 2 Duo processor with 2GB memory and also running Fedora Core 7. This test shows that using a single SPE is faster than the commodity processor, despite the overhead in terms of memory transfers and bookkeeping. This is caused by the vector-units residing in each SPE, enabling a boost...

  14. Nano scaffolds and stem cell therapy in liver tissue engineering

    Science.gov (United States)

    Montaser, Laila M.; Fawzy, Sherin M.

    2015-08-01

    Tissue engineering and regenerative medicine have been constantly developing of late due to the major progress in cell and organ transplantation, as well as advances in materials science and engineering. Although stem cells hold great potential for the treatment of many injuries and degenerative diseases, several obstacles must be overcome before their therapeutic application can be realized. These include the development of advanced techniques to understand and control functions of micro environmental signals and novel methods to track and guide transplanted stem cells. A major complication encountered with stem cell therapies has been the failure of injected cells to engraft to target tissues. The application of nanotechnology to stem cell biology would be able to address those challenges. Combinations of stem cell therapy and nanotechnology in tissue engineering and regenerative medicine have achieved significant advances. These combinations allow nanotechnology to engineer scaffolds with various features to control stem cell fate decisions. Fabrication of Nano fiber cell scaffolds onto which stem cells can adhere and spread, forming a niche-like microenvironment which can guide stem cells to proceed to heal damaged tissues. In this paper, current and emergent approach based on stem cells in the field of liver tissue engineering is presented for specific application. The combination of stem cells and tissue engineering opens new perspectives in tissue regeneration for stem cell therapy because of the potential to control stem cell behavior with the physical and chemical characteristics of the engineered scaffold environment.

  15. Review Article: The weak interactive characteristic of resonance cells and broadband effect of metamaterials

    OpenAIRE

    Xiaopeng Zhao; Kun Song

    2014-01-01

    Metamaterials are artificial media designed to control electromagnetic wave propagation. Due to resonance, most present-day metamaterials inevitably suffer from narrow bandwidth, extremely limiting their practical applications. On the basis of tailored properties, a metamaterial within which each distinct unit cell resonates at its inherent frequency and has almost no coupling effect with the other ones, termed as weak interaction system, can be formulated. The total response of a weak intera...

  16. Broadband light absorption enhancement in moth’s eye nanostructured organic solar cells

    Directory of Open Access Journals (Sweden)

    Weixia Lan

    2015-05-01

    Full Text Available A comprehensive study on inverted organic solar cells (OSCs with a moth’s eye nanostructured (MEN active layer was carried out. Performance of the MEN-based OSCs and the corresponding control planar cells, fabricated with blend of poly[4,8-bis[(2-ethylhexyloxy]benzo[1,2-b:4,5-bA] dithiophene-2, 6-diyl][3-fluoro-2-[(2- ethylhexyl carbonyl]thieno[3,4-b]-thiophenediyl] (PTB7:[6,6]- phenyl-C70- butyric-acid-methyl-ester (PC70BM was analyzed. The efficiency of the MEN-based OSCs was optimized by adjusting the height of MEN pattern in the active layer. Our experimental and theoretical results reveal that the MEN pattern enhances light absorption in the PTB7:PC70BM active layer, especially over the long wavelength region. This leads to a 7.8% increase in short circuit current density and a 6.1% increase in power conversion efficiency over those of the control planar cell.

  17. Endochondral bone tissue engineering using embryonic stem cells

    OpenAIRE

    Jukes, Jojanneke M.; Both, Sanne Karijn; Leusink, Anouk; Sterk, Lotus M. Th.; Blitterswijk, van, W.J.; Boer, de, J.W.

    2008-01-01

    Embryonic stem cells can provide an unlimited supply of pluripotent cells for tissue engineering applications. Bone tissue engineering by directly differentiating ES cells (ESCs) into osteoblasts has been unsuccessful so far. Therefore, we investigated an alternative approach, based on the process of endochondral ossification. A cartilage matrix was formed in vitro by mouse ESCs seeded on a scaffold. When these cartilage tissue-engineered constructs (CTECs) were implanted s.c., the cartilage ...

  18. Induced Pluripotent Stem Cells for Neural Tissue Engineering

    OpenAIRE

    Wang, Aijun; Tang, Zhenyu; Park, In-Hyun; Zhu, Yiqian; Patel, Shyam; Daley, George Q.; Song, Li

    2011-01-01

    Induced pluripotent stem cells (iPSCs) hold great promise for cell therapies and tissue engineering. Neural crest stem cells (NCSCs) are multipotent and represent a valuable system to investigate iPSC differentiation and therapeutic potential. Here we derived NCSCs from human iPSCs and embryonic stem cells (ESCs), and investigated the potential of NCSCs for neural tissue engineering. The differentiation of iPSCs and the expansion of derived NCSCs varied in different cell lines, but all NCSC l...

  19. An effective reflectance method for designing broadband antireflection films coupled with solar cells

    Institute of Scientific and Technical Information of China (English)

    Zhan Feng; He Ji-Fang; Shang Xiang-Jun; Li Mi-Feng; Ni Hai-Qiao; Xu Ying-Qiang; Niu Zhi-Chuan

    2012-01-01

    The solar spectrum covers a broad wavelength range,which requires that antireflection coating (ARC) is effective over a relatively wide wavelength range for more incident light coming into the cell.In this paper,we present two methods to measure the composite reflection of SiO2/ZnS double-layer ARC in the wavelength ranges of 300-870 nm (dualjunction) and 300-1850 nm (triple-junction),under the solar spectrum AM0.In order to give sufficient consideration to the ARC coupled with the window layer and the dispersion effect of the refractive index of each layer,we use multidimensional matrix data for reliable simulation.A comparison between the results obtained from the weighted-average reflectance (WAR) method commonly used and that from the effective-average reflectance (EAR) method introduced here shows that the optimized ARC through minimizing the effective-average reflectance is convenient and available.

  20. Broadband photocurrent enhancement and light-trapping in thin film Si solar cells with periodic Al nanoparticle arrays on the front

    DEFF Research Database (Denmark)

    Uhrenfeldt, Christian; Villesen, Thorbjørn Falk; Tetu, Amelie;

    2015-01-01

    Plasmonic resonances in metal nanoparticles are considered candidates for improved thin film Si photovoltaics. In periodic arrays the influence of collective modes can enhance the resonant properties of such arrays. We have investigated the use of periodic arrays of Al nanoparticles placed on the...... front of a thin film Si test solar cell. It is demonstrated that the resonances from the Al nanoparticle array cause a broadband photocurrent enhancement ranging from the ultraviolet to the infrared with respect to a reference cell. From the experimental results as well as from numerical simulations it...

  1. Cell Microenvironment Engineering and Monitoring for Tissue Engineering and Regenerative Medicine: The Recent Advances

    Science.gov (United States)

    Barthes, Julien; Özçelik, Hayriye; Hindié, Mathilde; Ndreu-Halili, Albana; Hasan, Anwarul

    2014-01-01

    In tissue engineering and regenerative medicine, the conditions in the immediate vicinity of the cells have a direct effect on cells' behaviour and subsequently on clinical outcomes. Physical, chemical, and biological control of cell microenvironment are of crucial importance for the ability to direct and control cell behaviour in 3-dimensional tissue engineering scaffolds spatially and temporally. In this review, we will focus on the different aspects of cell microenvironment such as surface micro-, nanotopography, extracellular matrix composition and distribution, controlled release of soluble factors, and mechanical stress/strain conditions and how these aspects and their interactions can be used to achieve a higher degree of control over cellular activities. The effect of these parameters on the cellular behaviour within tissue engineering context is discussed and how these parameters are used to develop engineered tissues is elaborated. Also, recent techniques developed for the monitoring of the cell microenvironment in vitro and in vivo are reviewed, together with recent tissue engineering applications where the control of cell microenvironment has been exploited. Cell microenvironment engineering and monitoring are crucial parts of tissue engineering efforts and systems which utilize different components of the cell microenvironment simultaneously can provide more functional engineered tissues in the near future. PMID:25143954

  2. Adoption of Broadband Services

    DEFF Research Database (Denmark)

    Falch, Morten

    2008-01-01

    Broadband is seen as a key infrastructure for developing the information society. For this reason many Governments are actively engaged in stimulating investments in broadband infrastructures and use of broadband services. This chapter compares a wide range of broadband strategies in the most...... successful markets for broadband. This is done through analysis of national policies in three European countries-Denmark, Sweden, and Germany-and the U.S., Japan, and South Korea. We concluded that successful implementation of broadband depends on the kind of policy measures to be taken at the national level...

  3. Cell Microenvironment Engineering and Monitoring for Tissue Engineering and Regenerative Medicine: The Recent Advances

    Directory of Open Access Journals (Sweden)

    Julien Barthes

    2014-01-01

    Full Text Available In tissue engineering and regenerative medicine, the conditions in the immediate vicinity of the cells have a direct effect on cells’ behaviour and subsequently on clinical outcomes. Physical, chemical, and biological control of cell microenvironment are of crucial importance for the ability to direct and control cell behaviour in 3-dimensional tissue engineering scaffolds spatially and temporally. In this review, we will focus on the different aspects of cell microenvironment such as surface micro-, nanotopography, extracellular matrix composition and distribution, controlled release of soluble factors, and mechanical stress/strain conditions and how these aspects and their interactions can be used to achieve a higher degree of control over cellular activities. The effect of these parameters on the cellular behaviour within tissue engineering context is discussed and how these parameters are used to develop engineered tissues is elaborated. Also, recent techniques developed for the monitoring of the cell microenvironment in vitro and in vivo are reviewed, together with recent tissue engineering applications where the control of cell microenvironment has been exploited. Cell microenvironment engineering and monitoring are crucial parts of tissue engineering efforts and systems which utilize different components of the cell microenvironment simultaneously can provide more functional engineered tissues in the near future.

  4. Engineering models and methods for industrial cell control

    DEFF Research Database (Denmark)

    Lynggaard, Hans Jørgen Birk; Alting, Leo

    1997-01-01

    This paper is concerned with the engineering, i.e. the designing and making, of industrial cell control systems. The focus is on automated robot welding cells in the shipbuilding industry. The industrial research project defines models and methods for design and implemen-tation of computer based....... Further, an engineering methodology is defined. The three elements enablers, architecture and methodology constitutes the Cell Control Engineering concept which has been defined and evaluated through the implementation of two cell control systems for robot welding cells in production at ODENSE STEEL...... SHIPYARD.It is concluded that cell control technology provides for increased performance in production systems, and that the Cell Control Engineering concept reduces the effort for providing and operating high quality and high functionality cell control solutions for the industry....

  5. Construction of Tissue Engineering Artificial Cornea with Skin Stem Cells

    Institute of Scientific and Technical Information of China (English)

    Yuan LIU; Yan JIN

    2005-01-01

    @@ 1 Introduction The clinical need for an alternative to donor corneal tissue has encouraged much interests in recent years. An artificial cornea must fulfill the functions of the cornea it replaces. More recently, the idea of a bio-engineered cornea has risen. Corneal equivalents have been reconstructed by tissue engineering method. Aim of this study is to construct an artificial rabbit cornea by employing tissue engineering method and to determine if skin stem cells have a role in tissue engineered cornea construction.

  6. Cell-Based Strategies for Meniscus Tissue Engineering

    OpenAIRE

    Wei Niu; Weimin Guo; Shufeng Han; Yun Zhu; Shuyun Liu; Quanyi Guo

    2016-01-01

    Meniscus injuries remain a significant challenge due to the poor healing potential of the inner avascular zone. Following a series of studies and clinical trials, tissue engineering is considered a promising prospect for meniscus repair and regeneration. As one of the key factors in tissue engineering, cells are believed to be highly beneficial in generating bionic meniscus structures to replace injured ones in patients. Therefore, cell-based strategies for meniscus tissue engineering play a ...

  7. Pharmacologic suppression of target cell recognition by engineered T cells expressing chimeric T-cell receptors.

    Science.gov (United States)

    Alvarez-Vallina, L; Yañez, R; Blanco, B; Gil, M; Russell, S J

    2000-04-01

    Adoptive therapy with autologous T cells expressing chimeric T-cell receptors (chTCRs) is of potential interest for the treatment of malignancy. To limit possible T-cell-mediated damage to normal tissues that weakly express the targeted tumor antigen (Ag), we have tested a strategy for the suppression of target cell recognition by engineered T cells. Jurkat T cells were transduced with an anti-hapten chTCR tinder the control of a tetracycline-suppressible promoter and were shown to respond to Ag-positive (hapten-coated) but not to Ag-negative target cells. The engineered T cells were then reacted with hapten-coated target cells at different effector to target cell ratios before and after exposure to tetracycline. When the engineered T cells were treated with tetracycline, expression of the chTCR was greatly decreased and recognition of the hapten-coated target cells was completely suppressed. Tetracycline-mediated suppression of target cell recognition by engineered T cells may be a useful strategy to limit the toxicity of the approach to cancer gene therapy. PMID:10811469

  8. Cell-Based Strategies for Meniscus Tissue Engineering

    Science.gov (United States)

    Niu, Wei; Guo, Weimin; Han, Shufeng; Zhu, Yun; Liu, Shuyun; Guo, Quanyi

    2016-01-01

    Meniscus injuries remain a significant challenge due to the poor healing potential of the inner avascular zone. Following a series of studies and clinical trials, tissue engineering is considered a promising prospect for meniscus repair and regeneration. As one of the key factors in tissue engineering, cells are believed to be highly beneficial in generating bionic meniscus structures to replace injured ones in patients. Therefore, cell-based strategies for meniscus tissue engineering play a fundamental role in meniscal regeneration. According to current studies, the main cell-based strategies for meniscus tissue engineering are single cell type strategies; cell coculture strategies also were applied to meniscus tissue engineering. Likewise, on the one side, the zonal recapitulation strategies based on mimicking meniscal differing cells and internal architectures have received wide attentions. On the other side, cell self-assembling strategies without any scaffolds may be a better way to build a bionic meniscus. In this review, we primarily discuss cell seeds for meniscus tissue engineering and their application strategies. We also discuss recent advances and achievements in meniscus repair experiments that further improve our understanding of meniscus tissue engineering. PMID:27274735

  9. Cell-Based Strategies for Meniscus Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Wei Niu

    2016-01-01

    Full Text Available Meniscus injuries remain a significant challenge due to the poor healing potential of the inner avascular zone. Following a series of studies and clinical trials, tissue engineering is considered a promising prospect for meniscus repair and regeneration. As one of the key factors in tissue engineering, cells are believed to be highly beneficial in generating bionic meniscus structures to replace injured ones in patients. Therefore, cell-based strategies for meniscus tissue engineering play a fundamental role in meniscal regeneration. According to current studies, the main cell-based strategies for meniscus tissue engineering are single cell type strategies; cell coculture strategies also were applied to meniscus tissue engineering. Likewise, on the one side, the zonal recapitulation strategies based on mimicking meniscal differing cells and internal architectures have received wide attentions. On the other side, cell self-assembling strategies without any scaffolds may be a better way to build a bionic meniscus. In this review, we primarily discuss cell seeds for meniscus tissue engineering and their application strategies. We also discuss recent advances and achievements in meniscus repair experiments that further improve our understanding of meniscus tissue engineering.

  10. Cell-scaffold interactions in the bone tissue engineering triad

    Directory of Open Access Journals (Sweden)

    CM Murphy

    2013-09-01

    Full Text Available Bone tissue engineering has emerged as one of the leading fields in tissue engineering and regenerative medicine. The success of bone tissue engineering relies on understanding the interplay between progenitor cells, regulatory signals, and the biomaterials/scaffolds used to deliver them – otherwise known as the tissue engineering triad. This review will discuss the roles of these fundamental components with a specific focus on the interaction between cell behaviour and scaffold structural properties. In terms of scaffold architecture, recent work has shown that pore size can affect both cell attachment and cellular invasion. Moreover, different materials can exert different biomechanical forces, which can profoundly affect cellular differentiation and migration in a cell type specific manner. Understanding these interactions will be critical for enhancing the progress of bone tissue engineering towards clinical applications.

  11. Genetically engineered immune privileged Sertoli cells

    OpenAIRE

    Kaur, Gurvinder; Long, Charles R.; Dufour, Jannette M.

    2012-01-01

    Sertoli cells are immune privileged cells, important for controlling the immune response to male germ cells as well as maintaining the tolerogenic environment in the testis. Additionally, ectopic Sertoli cells have been shown to survive and protect co-grafted cells when transplanted across immunological barriers. The survival of ectopic Sertoli cells has led to the idea that they could be used in cell based gene therapy. In this review, we provide a brief overview of testis immune privilege a...

  12. Engineering spinal fusion: evaluating ceramic materials for cell based tissue engineered approaches

    NARCIS (Netherlands)

    Wilson, C.E.

    2011-01-01

    The principal aim of this thesis was to advance the development of tissue engineered posterolateral spinal fusion by investigating the potential of calcium phosphate ceramic materials to support cell based tissue engineered bone formation. This was accomplished by developing several novel model syst

  13. Cell Patterning for Liver Tissue Engineering via Dielectrophoretic Mechanisms

    Directory of Open Access Journals (Sweden)

    Wan Nurlina Wan Yahya

    2014-07-01

    Full Text Available Liver transplantation is the most common treatment for patients with end-stage liver failure. However, liver transplantation is greatly limited by a shortage of donors. Liver tissue engineering may offer an alternative by providing an implantable engineered liver. Currently, diverse types of engineering approaches for in vitro liver cell culture are available, including scaffold-based methods, microfluidic platforms, and micropatterning techniques. Active cell patterning via dielectrophoretic (DEP force showed some advantages over other methods, including high speed, ease of handling, high precision and being label-free. This article summarizes liver function and regenerative mechanisms for better understanding in developing engineered liver. We then review recent advances in liver tissue engineering techniques and focus on DEP-based cell patterning, including microelectrode design and patterning configuration.

  14. Stem cell technology and engineering for cancer treatment

    OpenAIRE

    Sinh Truong Nguyen; Phuc Van Pham

    2015-01-01

    Stem cells are not only widely used for regenerative medicine, but are also considered as a useful tool for cancer treatment. For a long time, stem cells have been utilized to renew the immune system for radiation or chemotherapy treated patients. Recently, stem cells are being engineered to carry therapeutic reagents to target tumor sites. Cancer vaccines based on the knowledge of cancer stem cells have been studied and applied for cancer treatment. Induced pluripotent stem cells have been u...

  15. Fuel Cell Car Design Project for Freshman Engineering Courses

    Science.gov (United States)

    Duke, Steve R.; Davis, Virginia A.

    2014-01-01

    In the Samuel Ginn College of Engineering at Auburn University, we have integrated a semester long design project based on a toy fuel cell car into our freshman "Introduction to Chemical Engineering Class." The project provides the students a basic foundation in chemical reactions, energy, and dimensional analysis that facilitates…

  16. Energizing Engineering Students with Hydrogen Fuel Cell Project

    Science.gov (United States)

    Cannell, Nori; Zavaleta, Dan

    2010-01-01

    At Desert Vista High School, near Phoenix, Arizona, Perkins Innovation Grant funding is being used to fund a program that is helping to prepare students for careers in engineering by giving them hands-on experience in areas like hydrogen generation and fuel cell utilization. As one enters Dan Zavaleta's automotive and engineering classroom and lab…

  17. Metasurface Broadband Solar Absorber

    CERN Document Server

    Azad, A K; Sykora, M; Weisse-Bernstein, N R; Luk, T S; Taylor, A J; Dalvit, D A R; Chen, H -T

    2015-01-01

    We demonstrate a broadband, polarization independent, omnidirectional absorber based on a metallic metasurface architecture, which accomplishes greater than 90% absorptance in the visible and near-infrared range of the solar spectrum, and exhibits low emissivity at mid- and far-infrared wavelengths. The complex unit cell of the metasurface solar absorber consists of eight pairs of gold nano-resonators that are separated from a gold ground plane by a thin silicon dioxide spacer. Our experimental measurements reveal high-performance absorption over a wide range of incidence angles for both s- and p-polarizations. We also investigate numerically the frequency-dependent field and current distributions to elucidate how the absorption occurs within the metasurface structure. Furthermore, we discuss the potential use of our metasurface absorber design in solar thermophotovoltaics by exploiting refractory plasmonic materials.

  18. Metasurface Broadband Solar Absorber

    Science.gov (United States)

    Azad, Abul K.; Kort-Kamp, Wilton J. M.; Sykora, Milan; Weisse-Bernstein, Nina R.; Luk, Ting S.; Taylor, Antoinette J.; Dalvit, Diego A. R.; Chen, Hou-Tong

    2016-02-01

    We demonstrate a broadband, polarization independent, wide-angle absorber based on a metallic metasurface architecture, which accomplishes greater than 90% absorptance in the visible and near-infrared range of the solar spectrum, and exhibits low absorptivity (emissivity) at mid- and far-infrared wavelengths. The complex unit cell of the metasurface solar absorber consists of eight pairs of gold nano-resonators that are separated from a gold ground plane by a thin silicon dioxide spacer. Our experimental measurements reveal high-performance absorption over a wide range of incidence angles for both s- and p-polarizations. We also investigate numerically the frequency-dependent field and current distributions to elucidate how the absorption occurs within the metasurface structure.

  19. Design and demonstration of broadband thin planar diffractive acoustic lenses

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Wenqi; Xie, Yangbo; Konneker, Adam; Popa, Bogdan-Ioan; Cummer, Steven A., E-mail: cummer@ee.duke.edu [Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708 (United States)

    2014-09-08

    We present here two diffractive acoustic lenses with subwavelength thickness, planar profile, and broad operation bandwidth. Tapered labyrinthine unit cells with their inherently broadband effective material properties are exploited in our design. Both the measured and the simulated results are showcased to demonstrate the lensing effect over more than 40% of the central frequency. The focusing of a propagating Gaussian modulated sinusoidal pulse is also demonstrated. This work paves the way for designing diffractive acoustic lenses and more generalized phase engineering diffractive elements with labyrinthine acoustic metamaterials.

  20. Design and demonstration of broadband thin planar diffractive acoustic lenses

    International Nuclear Information System (INIS)

    We present here two diffractive acoustic lenses with subwavelength thickness, planar profile, and broad operation bandwidth. Tapered labyrinthine unit cells with their inherently broadband effective material properties are exploited in our design. Both the measured and the simulated results are showcased to demonstrate the lensing effect over more than 40% of the central frequency. The focusing of a propagating Gaussian modulated sinusoidal pulse is also demonstrated. This work paves the way for designing diffractive acoustic lenses and more generalized phase engineering diffractive elements with labyrinthine acoustic metamaterials.

  1. Numerical and experimental studies of mechanisms underlying the effect of pulsed broadband terahertz radiation on nerve cells

    Energy Technology Data Exchange (ETDEWEB)

    Duka, M V; Dvoretskaya, L N; Babelkin, N S; Khodzitskii, M K; Chivilikhin, S A; Smolyanskaya, O A [St. Petersburg National Research University of Information Technologies, Mechanics and Optics, St. Petersburg (Russian Federation)

    2014-08-31

    We have studied the mechanisms underlying the effect of pulsed broadband terahertz radiation on the growth of neurites of sensory ganglia using a comparative analysis of measured reflection spectra of ganglion neurites (in the frequency range 0.1 – 2.0 THz) and spectra obtained by numerical simulation with CST Microwave Studio. The observed changes are shown to be mainly due to pulse energy absorption in the ganglion neurites. Of particular interest are the observed single resonance frequencies related to resonance size effects, which can be used to irradiate ganglia in order to activate their growth. (laser biophotonics)

  2. Cell Processing Engineering for Regenerative Medicine : Noninvasive Cell Quality Estimation and Automatic Cell Processing.

    Science.gov (United States)

    Takagi, Mutsumi

    2016-01-01

    The cell processing engineering including automatic cell processing and noninvasive cell quality estimation of adherent mammalian cells for regenerative medicine was reviewed. Automatic cell processing necessary for the industrialization of regenerative medicine was introduced. The cell quality such as cell heterogeneity should be noninvasively estimated before transplantation to patient, because cultured cells are usually not homogeneous but heterogeneous and most protocols of regenerative medicine are autologous system. The differentiation level could be estimated by two-dimensional cell morphology analysis using a conventional phase-contrast microscope. The phase-shifting laser microscope (PLM) could determine laser phase shift at all pixel in a view, which is caused by the transmitted laser through cell, and might be more noninvasive and more useful than the atomic force microscope and digital holographic microscope. The noninvasive determination of the laser phase shift of a cell using a PLM was carried out to determine the three-dimensional cell morphology and estimate the cell cycle phase of each adhesive cell and the mean proliferation activity of a cell population. The noninvasive discrimination of cancer cells from normal cells by measuring the phase shift was performed based on the difference in cytoskeleton density. Chemical analysis of the culture supernatant was also useful to estimate the differentiation level of a cell population. A probe beam, an infrared beam, and Raman spectroscopy are useful for diagnosing the viability, apoptosis, and differentiation of each adhesive cell. PMID:25373455

  3. Can engineered "designer" T cells outsmart chronic hepatitis B?

    Science.gov (United States)

    Protzer, U; Abken, H

    2010-01-01

    More than 350 million people worldwide are persistently infected with human heptatitis B virus (HBV) and at risk to develop liver cirrhosis and hepatocellular carcinoma making long-term treatment necessary. While a vaccine is available and new antiviral drugs are being developed, elimination of persistently infected cells is still a major issue. Recent efforts in adoptive cell therapy are experimentally exploring immunotherapeutic elimination of HBV-infected cells by means of a biological attack with genetically engineered "designer" T cells. PMID:21188203

  4. Neural tissue engineering using embryonic and induced pluripotent stem cells

    OpenAIRE

    Willerth, Stephanie M.

    2011-01-01

    With the recent start of the first clinical trial evaluating a human embryonic stem cell-derived therapy for the treatment of acute spinal cord injury, it is important to review the current literature examining the use of embryonic stem cells for neural tissue engineering applications with a focus on diseases and disorders that affect the central nervous system. Embryonic stem cells exhibit pluripotency and thus can differentiate into any cell type found in the body, including those found in ...

  5. Assembly of cells and vesicles for organ engineering

    International Nuclear Information System (INIS)

    The development of materials and technologies for the assembly of cells and/or vesicles is a key for the next generation of tissue engineering. Since the introduction of the tissue engineering concept in 1993, various types of scaffolds have been developed for the regeneration of connective tissues in vitro and in vivo. Cartilage, bone and skin have been successfully regenerated in vitro, and these regenerated tissues have been applied clinically. However, organs such as the liver and pancreas constitute numerous cell types, contain small amounts of extracellular matrix, and are highly vascularized. Therefore, organ engineering will require the assembly of cells and/or vesicles. In particular, adhesion between cells/vesicles will be required for regeneration of organs in vitro. This review introduces and discusses the key technologies and materials for the assembly of cells/vesicles for organ regeneration. (topical review)

  6. Assembly of cells and vesicles for organ engineering

    Directory of Open Access Journals (Sweden)

    Tetsushi Taguchi

    2011-01-01

    Full Text Available The development of materials and technologies for the assembly of cells and/or vesicles is a key for the next generation of tissue engineering. Since the introduction of the tissue engineering concept in 1993, various types of scaffolds have been developed for the regeneration of connective tissues in vitro and in vivo. Cartilage, bone and skin have been successfully regenerated in vitro, and these regenerated tissues have been applied clinically. However, organs such as the liver and pancreas constitute numerous cell types, contain small amounts of extracellular matrix, and are highly vascularized. Therefore, organ engineering will require the assembly of cells and/or vesicles. In particular, adhesion between cells/vesicles will be required for regeneration of organs in vitro. This review introduces and discusses the key technologies and materials for the assembly of cells/vesicles for organ regeneration.

  7. Assembly of cells and vesicles for organ engineering

    Energy Technology Data Exchange (ETDEWEB)

    Taguchi, Tetsushi, E-mail: taguchi.tetsushi@nims.go.jp [Biofunctional Materials Unit, Nano-Bio Field, Materials Nanoarchitectonics (MANA), National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)

    2011-12-15

    The development of materials and technologies for the assembly of cells and/or vesicles is a key for the next generation of tissue engineering. Since the introduction of the tissue engineering concept in 1993, various types of scaffolds have been developed for the regeneration of connective tissues in vitro and in vivo. Cartilage, bone and skin have been successfully regenerated in vitro, and these regenerated tissues have been applied clinically. However, organs such as the liver and pancreas constitute numerous cell types, contain small amounts of extracellular matrix, and are highly vascularized. Therefore, organ engineering will require the assembly of cells and/or vesicles. In particular, adhesion between cells/vesicles will be required for regeneration of organs in vitro. This review introduces and discusses the key technologies and materials for the assembly of cells/vesicles for organ regeneration. (topical review)

  8. Assembly of cells and vesicles for organ engineering

    Science.gov (United States)

    Taguchi, Tetsushi

    2011-12-01

    The development of materials and technologies for the assembly of cells and/or vesicles is a key for the next generation of tissue engineering. Since the introduction of the tissue engineering concept in 1993, various types of scaffolds have been developed for the regeneration of connective tissues in vitro and in vivo. Cartilage, bone and skin have been successfully regenerated in vitro, and these regenerated tissues have been applied clinically. However, organs such as the liver and pancreas constitute numerous cell types, contain small amounts of extracellular matrix, and are highly vascularized. Therefore, organ engineering will require the assembly of cells and/or vesicles. In particular, adhesion between cells/vesicles will be required for regeneration of organs in vitro. This review introduces and discusses the key technologies and materials for the assembly of cells/vesicles for organ regeneration.

  9. Cell engineering: spearheading the next generation in healthcare

    Energy Technology Data Exchange (ETDEWEB)

    Jayasinghe, Suwan N [BioPhysics Group, Department of Mechanical Engineering, University College London, Torrington Place, London WC1E 7JE (United Kingdom)], E-mail: s.jayasinghe@ucl.ac.uk

    2008-09-01

    Manipulating living mammalian cells present fascinating possibilities for a plethora of applications within our healthcare. These imply several possibilities in tissue engineering and regenerative medicine, to those of a therapeutic nature. The physical sciences are increasingly playing a pivotal role in this endeavour by both advancing existing cell engineering technology and pioneering new protocols for the creation of biologically viable structures. In this paper, the author introduces several direct needle/channel/orifice-based cell engineering protocols, currently undergoing intense investigation for a whole host of bio-applications. Hence, each protocol's advantages and disadvantages are clearly identified, whilst recognizing their future biological and engineering challenges. In conclusion, a few selected biotechnological applications present possibilities where these protocols could undergo focused exploration. Successful development of these bio-protocols sees the emergence of unique future strategies within a clinical environment having far-reaching consequences for our healthcare.

  10. Rural Broadband At A Glance, 2009 Edition

    OpenAIRE

    Stenberg, Peter L.; Low, Sarah A

    2009-01-01

    Three-quarters of U.S. residents used the Internet to access information, education, and services in 2007. Broadband Internet access is becoming essential for both businesses and households; many compare its evolution to other technologies now considered common necessities—such as cars, electricity, televisions, microwave ovens, and cell phones. Although rural residents enjoy widespread access to the Internet, they are less likely to have high-speed, or broadband, Internet access than their u...

  11. Air intake and exhaust systems in fuel cell engines

    Energy Technology Data Exchange (ETDEWEB)

    Fuesser, R.; Weber, O. [Mann and Hummel (Germany)

    1999-07-01

    This paper describes the design and development of the air intake and exhaust system of a fuel cell powered road vehicle. In this instance the automotive supplier designed both the air intake and the exhaust system. The fuel cell engine gives a cold combustion effect making it possible to manufacture the exhaust from plastic materials. (UK)

  12. Broadband transmission EPR spectroscopy.

    Directory of Open Access Journals (Sweden)

    Wilfred R Hagen

    Full Text Available EPR spectroscopy employs a resonator operating at a single microwave frequency and phase-sensitive detection using modulation of the magnetic field. The X-band spectrometer is the general standard with a frequency in the 9-10 GHz range. Most (biomolecular EPR spectra are determined by a combination of the frequency-dependent electronic Zeeman interaction and a number of frequency-independent interactions, notably, electron spin - nuclear spin interactions and electron spin - electron spin interactions, and unambiguous analysis requires data collection at different frequencies. Extant and long-standing practice is to use a different spectrometer for each frequency. We explore the alternative of replacing the narrow-band source plus single-mode resonator with a continuously tunable microwave source plus a non-resonant coaxial transmission cell in an unmodulated external field. Our source is an arbitrary wave digital signal generator producing an amplitude-modulated sinusoidal microwave in combination with a broadband amplifier for 0.8-2.7 GHz. Theory is developed for coaxial transmission with EPR detection as a function of cell dimensions and materials. We explore examples of a doublet system, a high-spin system, and an integer-spin system. Long, straigth, helical, and helico-toroidal cells are developed and tested with dilute aqueous solutions of spin label hydroxy-tempo. A detection limit of circa 5 µM HO-tempo in water at 800 MHz is obtained for the present setup, and possibilities for future improvement are discussed.

  13. Broadband Telecommunications Benchmarking Study

    OpenAIRE

    2004-01-01

    This report assesses Ireland's competitiveness relative to 21 countries, with particular focus on the broadband telecommunications requirements of the enterprise sector. The report outlines strengths and weaknesses that currently exist and progress that has already been made. It also makes a series of recommendations to further promote the development of the broadband market in Ireland.

  14. The Broadband Buzz.

    Science.gov (United States)

    Buchanan, Bruce

    2003-01-01

    "Broadband," the term for a variety of high-speed Internet options, opens up many opportunities for online classroom learning. Challenges for school districts include keeping the network running, training teachers, and paying for it. A sidebar lists broadband resources. (MLF)

  15. Development of Cell-Responsive Nanophase Hydroxyapatite for Tissue Engineering

    Directory of Open Access Journals (Sweden)

    R. Murugan

    2007-01-01

    Full Text Available Scaffold plays a critical role in engineering bone tissues by providing necessary structural support for the cells to accommodate and guiding their growth in the three dimensional (3D space. Therefore, designing scaffold that mimic composition and structural aspects of the bone is of great importance to promote cell adhesion, cell-matrix interactions, osteointegration, tissue formation and continued function. Nanophase hydroxyapatite (HA is a class of bioceramic material that mimics the bone mineral in composition and structure and possesses unique capabilities for surface interactions with biological entities than conventional HA; therefore, it can be used as a scaffolding system in engineering bone tissues. This article reports synthesis, characterization, and evaluation of nanophase HA for use in bone tissue engineering and how the nanophase characteristics help the HA to promote cells/tissue growth with suitable experimental examples.

  16. Cell interactions in bone tissue engineering

    OpenAIRE

    Pirraco, Rogério; Marques, A. P.; Reis, R. L.

    2010-01-01

    Bone fractures, where the innate regenerative bone response is compromised, represent between 4 and 8 hundred thousands of the total fracture cases, just in the United States. Bone tissue engineering (TE) brought the notion that, in cases such as those, it was preferable to boost the healing process of bone tissue instead of just adding artificial parts that could never properly replace the native tissue. However, despite the hype, bone TE so far could not live up to its promises and...

  17. Cell interactions in bone tissue engineering

    OpenAIRE

    Pirraco, R. P.; Marques, A. P.; Reis, R. L.

    2009-01-01

    Abstract Bone fractures, where the innate regenerative bone response is compromised, represent between 4 and 8 hundred thousands of the total fracture cases, just in the United States. Bone tissue engineering (TE) brought the notion that, in cases such as those, it was preferable to boost the healing process of bone tissue instead of just adding artificial parts that could never properly replace the native tissue. However, despite the hype, bone TE so far could not live up to its promises and...

  18. Understanding broadband over power line

    CERN Document Server

    Held, Gilbert

    2006-01-01

    Understanding Broadband over Power Line explores all aspects of the emerging technology that enables electric utilities to provide support for high-speed data communications via their power infrastructure. This book examines the two methods used to connect consumers and businesses to the Internet through the utility infrastructure: the existing electrical wiring of a home or office; and a wireless local area network (WLAN) access point.Written in a practical style that can be understood by network engineers and non-technologists alike, this volume offers tutorials on electric utility infrastru

  19. Micro & nano-engineering of fuel cells

    CERN Document Server

    Leung, Dennis YC

    2015-01-01

    Fuel cells are clean and efficient energy conversion devices expected to be the next generation power source. During more than 17 decades of research and development, various types of fuel cells have been developed with a view to meet the different energy demands and application requirements. Scientists have devoted a great deal of time and effort to the development and commercialization of fuel cells important for our daily lives. However, abundant issues, ranging from mechanistic study to system integration, still need to be figured out before massive applications can be used. Miniaturizatio

  20. Cryopreservation of Cell/Scaffold Tissue-Engineered Constructs

    OpenAIRE

    Costa, Pedro F.; Dias, Ana F.; Reis, Rui L.; Gomes, Manuela E.

    2012-01-01

    The aim of this work was to study the effect of cryopreservation over the functionality of tissue-engineered constructs, analyzing the survival and viability of cells seeded, cultured, and cryopreserved onto 3D scaffolds. Further, it also evaluated the effect of cryopreservation over the properties of the scaffold material itself since these are critical for the engineering of most tissues and in particular, tissues such as bone. For this purpose, porous scaffolds, namely fiber meshes based o...

  1. Nanotechnology, Cell Culture and Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Kazutoshi Haraguchi

    2011-01-01

    Full Text Available We have fabricated new types of polymer hydrogels and polymer nanocomposites, i.e., nanocomposite gels (NC gels and soft, polymer nanocomposites (M-NCs: solid, with novel organic/inorganic network structures. Both NC gels and M-NCs were synthesized by in-situ free-radical polymerization in the presence of exfoliated clay platelets in aqueous systems and were obtained in various forms such as film, sheet, tube, coating, etc. and sizes with a wide range of clay contents. Here, disk-like inorganic clay nanoparticles act as multi-functional crosslinkers to form new types of network systems. Both NC gels and M-NCs have extraordinary optical and mechanical properties including ultra-high reversible extensibility, as well as a number of new characteristics relating to optical anisotropy, polymer/clay morphology, biocompatibility, stimuli-sensitive surfaces, micro-patterning, etc. For examples, the biological testing of medical devices, comprised of a sensitization test, an irritation test, an intracutaneous test and an in vitro cytotoxicity test,was carried out for NC gels and M-NCs. The safety of NC gels and M-NCs was confirmed in all tests. Also, the interaction of living tissue with NC gel was investigated in vivo by implantation in live goats; neither inflammation nor concrescence occurred around the NC gels. Furthermore, it was found that both N-NC gels consisting of poly(N-isopropylacrylamide(PNIPA/clay network and M-NCs consisting of poly(2-methoxyethyacrylate(PMEA/clay network show characteristic cell culture and subsequent cell detachment on their surfaces, although it was almost impossible to culture cells on conventional, chemically-crosslinked PNIPA hydrogels and chemically crossslinked PMEA, regardless of their crosslinker concentration. Various kinds of cells, such ashumanhepatoma cells (HepG2, normal human dermal fibroblast (NHDF, and human umbilical vein endothelial cells (HUVEC, could be cultured to be confluent on the surfaces of N

  2. Utilizing stem cells for three-dimensional neural tissue engineering.

    Science.gov (United States)

    Knowlton, Stephanie; Cho, Yongku; Li, Xue-Jun; Khademhosseini, Ali; Tasoglu, Savas

    2016-05-26

    Three-dimensional neural tissue engineering has made great strides in developing neural disease models and replacement tissues for patients. However, the need for biomimetic tissue models and effective patient therapies remains unmet. The recent push to expand 2D neural tissue engineering into the third dimension shows great potential to advance the field. Another area which has much to offer to neural tissue engineering is stem cell research. Stem cells are well known for their self-renewal and differentiation potential and have been shown to give rise to tissues with structural and functional properties mimicking natural organs. Application of these capabilities to 3D neural tissue engineering may be highly useful for basic research on neural tissue structure and function, engineering disease models, designing tissues for drug development, and generating replacement tissues with a patient's genetic makeup. Here, we discuss the vast potential, as well as the current challenges, unique to integration of 3D fabrication strategies and stem cells into neural tissue engineering. We also present some of the most significant recent achievements, including nerve guidance conduits to facilitate better healing of nerve injuries, functional 3D biomimetic neural tissue models, physiologically relevant disease models for research purposes, and rapid and effective screening of potential drugs. PMID:26890524

  3. Application of adult stem cells in neural tissue engineering

    Institute of Scientific and Technical Information of China (English)

    Lihong Piao; Wei Wang

    2006-01-01

    OBJECTTIVE:To investigate the progress in finding,isolation and culture.proliferation and differentiation,and application in neural tissue engineering of adult stem cells(ASCs).DATA SOURCES:Using the terms"adult stem cells,nerve,tissue engineering".we searched the PubMed for adult stem ceils-related studies published in English from January 2001 to August 2006.Meanwhile,we also performed a China National Knowledge Infrastructure(CNKI)search for homochronous correlative literatures on the computer by inputting the terms"adult stem cells,nerve,tissue engineering"in Chinese.texts were searched for.Inclusive criteria:①Literatures about the sources,distribution,culture.proliferation and differentiation.and application in the repair of neural ASCs by tissue engineering.②Articles recommended either by randomized.blind or by other methods were not excluded.Exclusive criteria:①Embryonic stem cells.②Review,repetitive study,case report,Meta analysis. DATA EXTRACTION:Totally 1 278 articles related to ASCs were collected,32 were involved and the other 1 246 were excluded. DATA SYNTHESIS:Adult stem cell has the ability of self-renewal.unceasing proliferation and transdifferentiation.It has wide source,which does not involved in ethical problems.It has advantages over embryonic stem cell.Studies on the isolation and culture,induction and differentiation and application in neural ASCs by tissue engineering contribute to obtaining considerable ASCs,so as to provide experimental and theoretical bases for CONCLUSION:ASCs play a very important role in neural tissue engineering.

  4. Solar cell as a self-oscillating heat engine

    International Nuclear Information System (INIS)

    Solar cells are engines converting energy supplied by the photon flux into work. All known types of macroscopic engines and turbines are also self-oscillating systems which yield a periodic motion at the expense of a usually non-periodic source of energy. The very definition of work in the formalism of quantum open systems suggests the hypothesis that the oscillating ‘piston’ is a necessary ingredient of the work extraction process. This aspect of solar cell operation is absent in the existing descriptions and the main goal of this paper is to show that plasma oscillations provide the physical implementation of a piston. (paper)

  5. Broadband adoption by SMES

    OpenAIRE

    Oni, Oluwasola

    2007-01-01

    This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University. Because the benefits of broadband for businesses have been widely publicized, the UK government has tried to ensure that there is a wide and fast take-up of the technology. Initial figures showed that broadband adoption by SMEs was particularly slow and there has been little research on the use of broadband by businesses, particularly SMEs. An in-depth study into the roles and activities of t...

  6. Cardiac tissue engineering and regeneration using cell-based therapy

    Directory of Open Access Journals (Sweden)

    Alrefai MT

    2015-05-01

    Full Text Available Mohammad T Alrefai,1–3 Divya Murali,4 Arghya Paul,4 Khalid M Ridwan,1,2 John M Connell,1,2 Dominique Shum-Tim1,2 1Division of Cardiac Surgery, 2Division of Surgical Research, McGill University Health Center, Montreal, QC, Canada; 3King Faisal Specialist Hospital and Research Center, Jeddah, Saudi Arabia; 4Department of Chemical and Petroleum Engineering, School of Engineering, University of Kansas, Lawrence, KS, USA Abstract: Stem cell therapy and tissue engineering represent a forefront of current research in the treatment of heart disease. With these technologies, advancements are being made into therapies for acute ischemic myocardial injury and chronic, otherwise nonreversible, myocardial failure. The current clinical management of cardiac ischemia deals with reestablishing perfusion to the heart but not dealing with the irreversible damage caused by the occlusion or stenosis of the supplying vessels. The applications of these new technologies are not yet fully established as part of the management of cardiac diseases but will become so in the near future. The discussion presented here reviews some of the pioneering works at this new frontier. Key results of allogeneic and autologous stem cell trials are presented, including the use of embryonic, bone marrow-derived, adipose-derived, and resident cardiac stem cells. Keywords: stem cells, cardiomyocytes, cardiac surgery, heart failure, myocardial ischemia, heart, scaffolds, organoids, cell sheet and tissue engineering

  7. Prospect of Stem Cells in Bone Tissue Engineering: A Review

    Directory of Open Access Journals (Sweden)

    Azizeh-Mitra Yousefi

    2016-01-01

    Full Text Available Mesenchymal stem cells (MSCs have been the subject of many studies in recent years, ranging from basic science that looks into MSCs properties to studies that aim for developing bioengineered tissues and organs. Adult bone marrow-derived mesenchymal stem cells (BM-MSCs have been the focus of most studies due to the inherent potential of these cells to differentiate into various cell types. Although, the discovery of induced pluripotent stem cells (iPSCs represents a paradigm shift in our understanding of cellular differentiation. These cells are another attractive stem cell source because of their ability to be reprogramed, allowing the generation of multiple cell types from a single cell. This paper briefly covers various types of stem cell sources that have been used for tissue engineering applications, with a focus on bone regeneration. Then, an overview of some recent studies making use of MSC-seeded 3D scaffold systems for bone tissue engineering has been presented. The emphasis has been placed on the reported scaffold properties that tend to improve MSCs adhesion, proliferation, and osteogenic differentiation outcomes.

  8. Engineered Biomaterials to Enhance Stem Cell-Based Cardiac Tissue Engineering and Therapy.

    Science.gov (United States)

    Hasan, Anwarul; Waters, Renae; Roula, Boustany; Dana, Rahbani; Yara, Seif; Alexandre, Toubia; Paul, Arghya

    2016-07-01

    Cardiovascular disease is a leading cause of death worldwide. Since adult cardiac cells are limited in their proliferation, cardiac tissue with dead or damaged cardiac cells downstream of the occluded vessel does not regenerate after myocardial infarction. The cardiac tissue is then replaced with nonfunctional fibrotic scar tissue rather than new cardiac cells, which leaves the heart weak. The limited proliferation ability of host cardiac cells has motivated investigators to research the potential cardiac regenerative ability of stem cells. Considerable progress has been made in this endeavor. However, the optimum type of stem cells along with the most suitable matrix-material and cellular microenvironmental cues are yet to be identified or agreed upon. This review presents an overview of various types of biofunctional materials and biomaterial matrices, which in combination with stem cells, have shown promises for cardiac tissue replacement and reinforcement. Engineered biomaterials also have applications in cardiac tissue engineering, in which tissue constructs are developed in vitro by combining stem cells and biomaterial scaffolds for drug screening or eventual implantation. This review highlights the benefits of using biomaterials in conjunction with stem cells to repair damaged myocardium and give a brief description of the properties of these biomaterials that make them such valuable tools to the field. PMID:26953627

  9. Tissue engineering a surrogate niche for metastatic cancer cells.

    Science.gov (United States)

    Seib, F Philipp; Berry, Janice E; Shiozawa, Yusuke; Taichman, Russell S; Kaplan, David L

    2015-05-01

    In breast and prostate cancer patients, the bone marrow is a preferred site of metastasis. We hypothesized that we could use tissue-engineering strategies to lure metastasizing cancer cells to tissue-engineered bone marrow. First, we generated highly porous 3D silk scaffolds that were biocompatible and amenable to bone morphogenetic protein 2 functionalization. Control and functionalized silk scaffolds were subcutaneously implanted in mice and bone marrow development was followed. Only functionalized scaffolds developed cancellous bone and red bone marrow, which appeared as early as two weeks post-implantation and further developed over the 16-week study period. This tissue-engineered bone marrow microenvironment could be readily manipulated in situ to understand the biology of bone metastasis. To test the ability of functionalized scaffolds to serve as a surrogate niche for metastasis, human breast cancer cells were injected into the mammary fat pads of mice. The treatment of animals with scaffolds had no significant effect on primary tumor growth. However, extensive metastasis was observed in functionalized scaffolds, and the highest levels for scaffolds that were in situ manipulated with receptor activator of nuclear factor kappa-B ligand (RANKL). We also applied this tissue-engineered bone marrow model in a prostate cancer and experimental metastasis setting. In summary, we were able to use tissue-engineered bone marrow to serve as a target or "trap" for metastasizing cancer cells. PMID:25771021

  10. Engineered T Cells for the Adoptive Therapy of B-Cell Chronic Lymphocytic Leukaemia

    Directory of Open Access Journals (Sweden)

    Philipp Koehler

    2012-01-01

    Full Text Available B-cell chronic lymphocytic leukaemia (B-CLL remains an incurable disease due to the high risk of relapse, even after complete remission, raising the need to control and eliminate residual tumor cells in long term. Adoptive T cell therapy with genetically engineered specificity is thought to fulfil expectations, and clinical trials for the treatment of CLL are initiated. Cytolytic T cells from patients are redirected towards CLL cells by ex vivo engineering with a chimeric antigen receptor (CAR which binds to CD19 on CLL cells through an antibody-derived domain and triggers T cell activation through CD3ζ upon tumor cell engagement. Redirected T cells thereby target CLL cells in an MHC-unrestricted fashion, secret proinflammatory cytokines, and eliminate CD19+ leukaemia cells with high efficiency. Cytolysis of autologous CLL cells by patient's engineered T cells is effective, however, accompanied by lasting elimination of healthy CD19+ B-cells. In this paper we discuss the potential of the strategy in the treatment of CLL, the currently ongoing trials, and the future challenges in the adoptive therapy with CAR-engineered T cells.

  11. Engineering Cell and Tissue Mechanical Microenvironments for Regenerative Medicine

    OpenAIRE

    Tsou, Danielle An-Chi

    2012-01-01

    One of the goals of tissue engineering is to create technologies that will improve or replace biological function of diseased or damaged cells and tissues. The purpose of my thesis work is to determine how the mechanical properties of the murine microenvironment, specifically matrix stiffness, can affect the function and behavior of cells and tissues. Previous research has shown that stiffness is a powerful mechanical property; it is associated with breast and liver cancer, and can also be ...

  12. Tissue Engineering Bone Using Autologous Progenitor Cells in the Peritoneum

    OpenAIRE

    Jinhui Shen; Ashwin Nair; Ramesh Saxena; Cheng Cheng Zhang; Joseph Borrelli; Liping Tang

    2014-01-01

    Despite intensive research efforts, there remains a need for novel methods to improve the ossification of scaffolds for bone tissue engineering. Based on a common phenomenon and known pathological conditions of peritoneal membrane ossification following peritoneal dialysis, we have explored the possibility of regenerating ossified tissue in the peritoneum. Interestingly, in addition to inflammatory cells, we discovered a large number of multipotent mesenchymal stem cells (MSCs) in the periton...

  13. Nanoscale tissue engineering: spatial control over cell-materials interactions

    Energy Technology Data Exchange (ETDEWEB)

    Wheeldon, Ian; Farhadi, Arash; Bick, Alexander G; Khademhosseini, Ali [Center for Biomedical Engineering, Department of Medicine, Brigham and Women' s Hospital, Harvard Medical School, Boston, MA 02115 (United States); Jabbari, Esmaiel, E-mail: alik@rics.bwh.harvard.edu [Department of Chemical Engineering, University of South Carolina, Columbia, SC 29208 (United States)

    2011-05-27

    Cells interact with the surrounding environment by making tens to hundreds of thousands of nanoscale interactions with extracellular signals and features. The goal of nanoscale tissue engineering is to harness these interactions through nanoscale biomaterials engineering in order to study and direct cellular behavior. Here, we review two- and three-dimensional (2- and 3D) nanoscale tissue engineering technologies, and provide a holistic overview of the field. Techniques that can control the average spacing and clustering of cell adhesion ligands are well established and have been highly successful in describing cell adhesion and migration in 2D. Extension of these engineering tools to 3D biomaterials has created many new hydrogel and nanofiber scaffold technologies that are being used to design in vitro experiments with more physiologically relevant conditions. Researchers are beginning to study complex cell functions in 3D. However, there is a need for biomaterials systems that provide fine control over the nanoscale presentation of bioactive ligands in 3D. Additionally, there is a need for 2- and 3D techniques that can control the nanoscale presentation of multiple bioactive ligands and that can control the temporal changes in the cellular microenvironment. (topical review)

  14. Nanoscale tissue engineering: spatial control over cell-materials interactions

    International Nuclear Information System (INIS)

    Cells interact with the surrounding environment by making tens to hundreds of thousands of nanoscale interactions with extracellular signals and features. The goal of nanoscale tissue engineering is to harness these interactions through nanoscale biomaterials engineering in order to study and direct cellular behavior. Here, we review two- and three-dimensional (2- and 3D) nanoscale tissue engineering technologies, and provide a holistic overview of the field. Techniques that can control the average spacing and clustering of cell adhesion ligands are well established and have been highly successful in describing cell adhesion and migration in 2D. Extension of these engineering tools to 3D biomaterials has created many new hydrogel and nanofiber scaffold technologies that are being used to design in vitro experiments with more physiologically relevant conditions. Researchers are beginning to study complex cell functions in 3D. However, there is a need for biomaterials systems that provide fine control over the nanoscale presentation of bioactive ligands in 3D. Additionally, there is a need for 2- and 3D techniques that can control the nanoscale presentation of multiple bioactive ligands and that can control the temporal changes in the cellular microenvironment. (topical review)

  15. Engineered CHO cells for production of diverse, homogeneous glycoproteins

    DEFF Research Database (Denmark)

    Yang, Zhang; Wang, Shengjun; Halim, Adnan; Schulz, Morten Alder; Frodin, Morten; Rahman, Shamim H.; Vester-Christensen, Malene Bech; Behrens, Carsten; Kristensen, Claus; Vakhrushev, Sergey Y.; Bennett, Eric Paul; Wandall, Hans H.; Clausen, Henrik

    2015-01-01

    genes controlling N-glycosylation in CHO cells and constructed a design matrix that facilitates the generation of desired glycosylation, such as human-like alpha 2,6-linked sialic acid capping. This engineering approach will aid the production of glycoproteins with improved properties and therapeutic...

  16. Mammalian designer cells: Engineering principles and biomedical applications.

    Science.gov (United States)

    Xie, Mingqi; Fussenegger, Martin

    2015-07-01

    Biotechnology is a widely interdisciplinary field focusing on the use of living cells or organisms to solve established problems in medicine, food production and agriculture. Synthetic biology, the science of engineering complex biological systems that do not exist in nature, continues to provide the biotechnology industry with tools, technologies and intellectual property leading to improved cellular performance. One key aspect of synthetic biology is the engineering of deliberately reprogrammed designer cells whose behavior can be controlled over time and space. This review discusses the most commonly used techniques to engineer mammalian designer cells; while control elements acting on the transcriptional and translational levels of target gene expression determine the kinetic and dynamic profiles, coupling them to a variety of extracellular stimuli permits their remote control with user-defined trigger signals. Designer mammalian cells with novel or improved biological functions not only directly improve the production efficiency during biopharmaceutical manufacturing but also open the door for cell-based treatment strategies in molecular and translational medicine. In the future, the rational combination of multiple sets of designer cells could permit the construction and regulation of higher-order systems with increased complexity, thereby enabling the molecular reprogramming of tissues, organisms or even populations with highest precision. PMID:26010998

  17. Omnidirectional and broadband optical absorption enhancement in small molecule organic solar cells by a patterned MoO3/Ag/MoO3 transparent anode

    Science.gov (United States)

    Tian, Ximin; Hao, Yuying; Zhang, Ye; Cui, Yanxia; Ji, Ting; Wang, Hua; Wei, Bin; Huang, Wei

    2015-03-01

    We designed and calculated a novel organic solar cell (OSC) with MoO3/Ag/MoO3 (MAM) grating as transparent anode and the patterned copper phthalocyanine (CuPc)/fullerence (C60) as active layer. The numerical results indicate that a broadband, omnidirectional light absorption enhancement is realized by utilizing such a one-dimensional (1D) grating with core-shell structure. The total absorption efficiency of the active layer over the wavelength range from 400 to 900 nm is enhanced by 178.88%, 19.44% and 99.16% relative to the equivalent planar cell considering the weight of air-mass 1.5 global (AM 1.5G) solar spectrum at normally incident transverse magnetic (TM), transverse electric (TE) and TM/TE hybrid polarized light, respectively. The improved light trapping is attributed to the multiple modes hybridization of propagating surface plasmon polaritons (SPPs), localized surface plasmons (LSPs) and the strong coupling of SPP waves at TM polarization along with the Floquet modes at TE polarization. Furthermore, the proposed optimized architecture also exhibits an expected short-circuit current density (Jsc) with the value of 11.11 mA/cm2 in theory, which is increased by 116.6% compared with that of the planar control device.

  18. Cell sheet approach for tissue engineering and regenerative medicine.

    Science.gov (United States)

    Matsuura, Katsuhisa; Utoh, Rie; Nagase, Kenichi; Okano, Teruo

    2014-09-28

    After the biotech medicine era, regenerative medicine is expected to be an advanced medicine that is capable of curing patients with difficult-to-treat diseases and physically impaired function. Our original scaffold-free cell sheet-based tissue engineering technology enables transplanted cells to be engrafted for a long time, while fully maintaining their viability. This technology has already been applied to various diseases in the clinical setting, including the cornea, esophagus, heart, periodontal ligament, and cartilage using autologous cells. Transplanted cell sheets not only replace the injured tissue and compensate for impaired function, but also deliver growth factors and cytokines in a spatiotemporal manner over a prolonged period, which leads to promotion of tissue repair. Moreover, the integration of stem cell biology and cell sheet technology with sufficient vascularization opens possibilities for fabrication of human three-dimensional vascularized dense and intact tissue grafts for regenerative medicine to parenchymal organs. PMID:24858800

  19. Upgrades of Hanford Engineering Development Laboratory hot cell facilities

    International Nuclear Information System (INIS)

    The Hanford Engineering Development Laboratory operates the 327 Postirradiation Testing Laboratory (PITL) and the 324 Shielded Materials Facility (SMF). These hot cell facilities provide diverse capabilities for the postirradiation examination and testing of irradiated reactor fuels and materials. The primary function of these facilities is to determine failure mechanisms and effects of irradiation on physical and mechanical properties of reactor components. The purpose of this paper is to review major equipment and facility upgrades that enhance customer satisfaction and broaden the engineering capabilities for more diversified programs. These facility and system upgrades are providing higher quality remote nondestructive and destructive examination services with increased productivity, operator comfort, and customer satisfaction

  20. Engineering a clinically-useful matrix for cell therapy.

    Science.gov (United States)

    Prestwich, Glenn D

    2008-01-01

    The design criteria for matrices for encapsulation of cells for cell therapy include chemical, biological, engineering, marketing, regulatory, and financial constraints. What is required is a biocompatible material for culture of cells in three-dimensions (3-D) that offers ease of use, experimental flexibility to alter composition and compliance, and a composition that would permit a seamless transition from in vitro to in vivo use. The challenge is to replicate the complexity of the native extracellular matrix (ECM) environment with the minimum number of components necessary to allow cells to rebuild a given tissue. Our approach is to deconstruct the ECM to a few modular components that can be reassembled into biomimetic materials that meet these criteria. These semi-synthetic ECMs (sECMs) employ thiol-modified derivatives of hyaluronic acid (HA) that can form covalently crosslinked, biodegradable hydrogels. These sECMs are "living" biopolymers, meaning that they can be crosslinked in the presence of cells or tissues to enable cell therapy and tissue engineering. Moreover, the sECMs allow inclusion of the appropriate biological cues needed to simulate the complexity of the ECM of a given tissue. Taken together, the sECM technology offers a manufacturable, highly reproducible, flexible, FDA-approvable, and affordable vehicle for cell expansion and differentiation in 3-D. PMID:19279714

  1. Defect engineering in solar cell manufacturing and thin film solar cell development

    Energy Technology Data Exchange (ETDEWEB)

    Sopori, B.L. [National Renewable Energy Lab., Golden, CO (United States)

    1995-08-01

    During the last few years many defect engineering concepts were successfully applied to fabricate high efficiency silicon solar cells on low-cost substrates. Some of the research advances are described.

  2. Engineering novel cell surface chemistry for selective tumor cell targeting

    Energy Technology Data Exchange (ETDEWEB)

    Bertozzi, C.R. [Univ. of California, Berkeley, CA (United States)]|[Lawrence Berkeley National Lab., CA (United States)

    1997-12-31

    A common feature of many different cancers is the high expression level of the two monosaccharides sialic acid and fucose within the context of cell-surface associated glycoconjugates. A correlation has been made between hypersialylation and/or hyperfucosylation and the highly metastatic phenotype. Thus, a targeting strategy based on sialic acid or fucose expression would be a powerful tool for the development of new cancer cell-selective therapies and diagnostic agents. We have discovered that ketone groups can be incorporated metabolically into cell-surface associated sialic acids. The ketone is can be covalently ligated with hydrazide functionalized proteins or small molecules under physiological conditions. Thus, we have discovered a mechanism to selectively target hydrazide conjugates to highly sialylated cells such as cancer cells. Applications of this technology to the generation of novel cancer cell-selective toxins and MRI contrast reagents will be discussed, in addition to progress towards the use of cell surface fucose residues as vehicles for ketone expression.

  3. Genetic Engineering of Mesenchymal Stem Cells for Regenerative Medicine.

    Science.gov (United States)

    Nowakowski, Adam; Walczak, Piotr; Janowski, Miroslaw; Lukomska, Barbara

    2015-10-01

    Mesenchymal stem cells (MSCs), which can be obtained from various organs and easily propagated in vitro, are one of the most extensively used types of stem cells and have been shown to be efficacious in a broad set of diseases. The unique and highly desirable properties of MSCs include high migratory capacities toward injured areas, immunomodulatory features, and the natural ability to differentiate into connective tissue phenotypes. These phenotypes include bone and cartilage, and these properties predispose MSCs to be therapeutically useful. In addition, MSCs elicit their therapeutic effects by paracrine actions, in which the metabolism of target tissues is modulated. Genetic engineering methods can greatly amplify these properties and broaden the therapeutic capabilities of MSCs, including transdifferentiation toward diverse cell lineages. However, cell engineering can also affect safety and increase the cost of therapy based on MSCs; thus, the advantages and disadvantages of these procedures should be discussed. In this review, the latest applications of genetic engineering methods for MSCs with regenerative medicine purposes are presented. PMID:26140302

  4. The Integration of Nanotechnology and Biology for Cell Engineering: Promises and Challenges

    Directory of Open Access Journals (Sweden)

    Uma Maheswari Krishnan

    2013-10-01

    their variants, self-assembly, cell-printing techniques and cell sheet engineering, have all been elaborated in detail. These novel techniques may serve to overcome the challenges currently faced in tissue engineering.

  5. Monitoring cell profile in tissue engineered constructs by OCT

    Science.gov (United States)

    Yang, Ying; Bagnaninchi, Pierre O.; Wood, Mairead A.; El Haj, Alicia J.; Guyot, Elvire; Dubois, Arnaud; Wang, Ruikang K.

    2005-04-01

    Despite significant progress in tissue engineering over the last decade, the development of real-time, non-destructive tools for monitoring the development of engineered tissues remains a great challenge. To date, the evaluation of cell proliferation and extracellular matrix production in response to various culture conditions depends upon traditional DNA, RNA and protein analysis which requires extraction of cell components from constructs resulting in loss of tissue morphology and integrity. In this study, we report how optical coherence tomography (OCT) can be exploited to monitor cell profiles in real-time and in a non-destructive manner. Scaffolds made from poly(lactic acid) (PLLA) with various porosities were scanned by OCT. A local porosity analysis method has been developed to quantify the porosity change. The hypothesis is whether the local porosity analysis can correlate with the tissue growth within the scaffold following seeding of the cells within it. Bone cells have been grown in the PLLA scaffolds under different culture conditions. The OCT images of these scaffolds have been collected. It has been found that the porosity of the cultured scaffold-cell constructs reduced under different culture conditions compared to blank scaffolds. A decrease in light penetration depth in OCT images has also been observed. There existed a good relationship between the local porosity and tissue growth. It has been demonstrated that the mean local porosity based on OCT images can become a unique method to correlate and monitor tissue growth.

  6. Temperature-Responsive Polymer Modified Surface for Cell Sheet Engineering

    Directory of Open Access Journals (Sweden)

    Teruo Okano

    2012-08-01

    Full Text Available In the past two decades, as a novel approach for tissue engineering, cell sheet engineering has been proposed by our laboratory. Poly(N-isopropylacrylamide (PIPAAm, which is a well-known temperature-responsive polymer, has been grafted on tissue culture polystyrene (TCPS surfaces through an electron beam irradiated polymerization. At 37 °C, where the PIPAAm modified surface is hydrophobic, cells can adhere, spread on the surface and grow to confluence. By decreasing temperature to 20 °C, since the surface turns to hydrophilic, cells can detach themselves from the surface spontaneously and form an intact cell sheet with extracellular matrix. For obtaining a temperature-induced cell attachment and detachment, it is necessary to immobilize an ultra thin PIPAAm layer on the TCPS surfaces. This review focuses on the characteristics of PIAPAm modified surfaces exhibiting these intelligent properties. In addition, PIPAAm modified surfaces giving a rapid cell-sheet recovery has been further developed on the basis of the characteristic of the PIPAAm surface. The designs of temperature-responsive polymer layer have provided an enormous potential to fabricate clinically applicable regenerative medicine.

  7. Broadband and Low-Loss Plasmonic Light Trapping in Dye-Sensitized Solar Cells Using Micrometer-Scale Rodlike and Spherical Core-Shell Plasmonic Particles.

    Science.gov (United States)

    Malekshahi Byranvand, Mahdi; Nemati Kharat, Ali; Taghavinia, Nima; Dabirian, Ali

    2016-06-29

    Dielectric scattering particles have widely been used as embedded scattering elements in dye-sensitized solar cells (DSCs) to improve the optical absorption of the device. Here we systematically study rodlike and spherical core-shell silica@Ag particles as more effective alternatives to the dielectric scattering particles. The wavelength-scale silica@Ag particles with sufficiently thin Ag shell support hybrid plasmonic-photonic resonance modes that have low parasitic absorption losses and a broadband optical response. Both of these features lead to their successful deployment in light trapping in high-efficiency DSCs. Optimized rodlike silica@Ag@silica particles improve the power conversion efficiency of a DSC from 6.33 to 8.91%. The dimension, surface morphology, and concentration of these particles are optimized to achieve maximal efficiency enhancement. The rodlike silica particles are prepared in a simple one-pot synthesis process and then are coated with Ag in a liquid-phase deposition process by reducing an Ag salt. The aspect ratio of silica rods is tuned by adjusting the temperature and duration of the growth process, whereas the morphology of Ag shell is tailored by controlling the reduction rate of Ag salt, where slower reduction in a polyol process gives a smoother Ag shell. Using optical calculations, the superior performance of the plasmonic core-shell particles is related to the large number of hybrid photonic-plasmonic resonance modes that they support. PMID:27300764

  8. Direct UV-written broadband directional broadband planar waveguide couplers

    DEFF Research Database (Denmark)

    Olivero, Massimo; Svalgaard, Mikael

    2005-01-01

    We report the fabrication of broadband directional couplers by direct UV-writing. The fabrication process is shown to be beneficial, robust and flexible. The components are compact and show superior performance in terms of loss and broadband operation.......We report the fabrication of broadband directional couplers by direct UV-writing. The fabrication process is shown to be beneficial, robust and flexible. The components are compact and show superior performance in terms of loss and broadband operation....

  9. Influence of engineered surface on cell directionality and motility

    International Nuclear Information System (INIS)

    Control of cell migration is important in numerous key biological processes, and is implicated in pathological conditions such as cancer metastasis and inflammatory diseases. Many previous studies indicated that cell migration could be guided by micropatterns fabricated on cell culture surfaces. In this study, we designed a polydimethylsiloxane cell culture substrate with gratings punctuated by corners and ends, and studied its effects on the behavior of MC3T3-E1 osteoblast cells. MC3T3-E1 cells elongated and aligned with the gratings, and the migration paths of the cells appeared to be guided by the grating pattern. Interestingly, more than 88% of the cells cultured on these patterns were observed to reverse their migration directions at least once during the 16 h examination period. Most of the reversal events occurred at the corners and the ends of the pattern, suggesting these localized topographical features induce an abrupt loss in directional persistence. Moreover, the cell speed was observed to increase temporarily right after each directional reversal. Focal adhesion complexes were more well-established in cells on the angular gratings than on flat surfaces, but the formation of filipodia appeared to be imbalanced at the corners and the ends, possibly leading to the loss of directional persistence. This study describes the first engineered cell culture surface that consistently induces changes in the directional persistence of adherent cells. This will provide an experimental model for the study of this phenomenon and a valuable platform to control the cell motility and directionality, which can be used for cell screening and selection. (paper)

  10. Broadband Visible Light Induced NO Formation

    Science.gov (United States)

    Lubart, Rachel; Eichler, Maor; Friedmann, Harry; Savion, N.; Breitbart, Haim; Ankri, Rinat

    2009-06-01

    Nitric oxide formation is a potential mechanism for photobiomodulation because it is synthesized in cells by nitric oxide synthase (NOS), which contains both flavin and heme, and thus absorbs visible light. The purpose of this work was to study broadband visible light induced NO formation in various cells. Cardiac, endothelial, sperm cells and RAW 264.7 macrophages were illuminated with broadband visible light, 40-130 mW/cm2, 2.4-39 J/cm2, and nitric oxide production was quantified by using the Griess reagent. The results showed that visible light illumination increased NO concentration both in sperm and endothelial cells, but not in cardiac cells. Activation of RAW 264.7 macrophages was very small. It thus appears that NO is involved in photobiomodulation, though different light parameters and illumination protocols are needed to induce NO in various cells.

  11. Broadband Visible Light Induced NO Formation

    International Nuclear Information System (INIS)

    Nitric oxide formation is a potential mechanism for photobiomodulation because it is synthesized in cells by nitric oxide synthase (NOS), which contains both flavin and heme, and thus absorbs visible light. The purpose of this work was to study broadband visible light induced NO formation in various cells. Cardiac, endothelial, sperm cells and RAW 264.7 macrophages were illuminated with broadband visible light, 40-130 mW/cm2, 2.4-39 J/cm2, and nitric oxide production was quantified by using the Griess reagent. The results showed that visible light illumination increased NO concentration both in sperm and endothelial cells, but not in cardiac cells. Activation of RAW 264.7 macrophages was very small. It thus appears that NO is involved in photobiomodulation, though different light parameters and illumination protocols are needed to induce NO in various cells.

  12. Tissue engineered heart valves based on human cells

    OpenAIRE

    Schmidt, D.; Hoerstrup, S P

    2006-01-01

    Valvular heart disease is still a significant cause of morbidity and mortality worldwide. Clinically used valve replacements including mechanical valves as well as fixed biological xeno- or homografts are associated with several major disadvantages. Alternatively, tissue engineering aims at the fabrication of autologous living cardiovascular replacements with the potential to grow and to repair, particularly for paediatric applications. Therefore, autologous cells are harvested and seeded ont...

  13. Tissue engineered heart valves based on human cells

    OpenAIRE

    Schmidt, D.; Hoerstrup, S P

    2007-01-01

    Valvular heart disease is still a significant cause of morbidity and mortality worldwide. Clinically used valve replacements including mechanical valves as well as fixed biological xeno- or homografts are associated with several major disadvantages. Alternatively, tissue engineering aims at the fabrication of autologous living cardiovascular replacements with the potential to grow and to repair, particularly for paediatric applications. Therefore, autologous cells are harvested and seeded ont...

  14. An estimation’s method at most attainable of length path in fixed broadband wireless access: engineering-maintenance of the calculation

    OpenAIRE

    Panteleev, Victor V.

    2012-01-01

    Methods of the engineering evaluation at most attainable lengths of the part in fixed radio systems with detailed conclusion of the equation of distance is offered. It’s discussed technological spare on expected Noise Margin (NM) on base 5-th balls scale criterion Mean Opinion Score (MOS) Quality-of-Service (QoS) of digital telecommunications under subjective perception Quality-of-Experience (QoE).

  15. Engineering the Interface Between Inorganic Materials and Cells

    Energy Technology Data Exchange (ETDEWEB)

    Schaffer, David

    2014-05-31

    To further optimize cell function in hybrid “living materials”, it would be advantageous to render mammalian cells responsive to novel “orthogonal” cues, i.e. signals they would not ordinarily respond to but that can be engineered to feed into defined intracellular signaling pathways. We recently developed an optogenetic method, based on A. thaliana Cry2, for rapid and reversible protein oligomerization in response to blue light. We also demonstrated the ability to use this method to channel the light input into several defined signaling pathways, work that will enhance communication between inorganic devices and living systems.

  16. Engineered microtopographies and surface chemistries direct cell attachment and function

    Science.gov (United States)

    Magin, Chelsea Marie

    Harrison, in 1914, first recognized that cells respond to physicochemical cues such as substratum topography when he observed that fibroblasts elongated while cultured on spider silk. Recently, techniques developed in the micro-electronics industry have been used to create molds for producing microscaled topographies with various shapes and spatial arrangements. Although these patterning techniques are well-established, very little is known about the mechanisms underlying cell sensing and response to microtopographies. In this work cellular micro-environments with varying surface topographies and chemistries were evaluated with marine organisms and mammalian cells to investigate cellular sensing and response. Biofouling---the accumulation of micro-organisms, plants, and animals on submerged surfaces---is an environmental and economic concern. Engineered topographies, replicated in polydimethylsiloxane elastomer (PDMSe) and functionalized poly(ethylene glycol)-dimethacrylate (PEGDMA) hydrogels, were evaluated for inhibition of marine fouling organism attachment. Microtopographies replicated in PDMSe inhibited attachment of the marine bacterium, Cobetia marina up to 99% versus smooth. The average normalized attachment densities of cells of C. marina and zoospores of the green algae Ulva on PDMSe topographies scaled inversely with the Engineered Roughness Index (ERIII), a representation of surface energy. Attachment densities of Ulva from four assays and C. marina from two growth phases to PDMSe surfaces scaled inversely with one equation: ERI II multiplied by the Reynolds number of the organism (Re) (R 2 = 0.77). The same microtopographies created in PDMSe reduced the initial attachment density and attachment strength of cells of the diatoms Navicula incerta and Seminavis robusta compared to smooth PDMSe. The average normalized attachment density of Navicula after exposure to shear stress (48 Pa) was correlated with the contact area between the diatom and a

  17. A broadband-sensitive upconverter La(Ga0.5Sc0.5)O3:Er,Ni,Nb for crystalline silicon solar cells

    International Nuclear Information System (INIS)

    We have developed an upconverter that significantly broadens the sensitive range, to overcome the shortcoming that conventional Er3+-doped upconverters used for crystalline silicon solar cells can utilize only a small portion of the solar spectrum at around 1.55 μm. We have designed the combination of the sensitizers and host material to utilize photons not absorbed by silicon or Er3+ ions. Ni2+ ions have been selected as the sensitizers that absorb photons in the wavelength range between the silicon absorption edge (1.1 μm) and the Er3+ absorption band and transfer the energies to the Er3+ emitters, with La(Ga,Sc)O3 as the host material. The Ga to Sc ratio has been optimized to tune the location of the Ni2+ absorption band for sufficient energy transfer. Co-doping with Nb5+ ions is needed for charge balance to introduce divalent Ni2+ ions into the trivalent Ga3+ and Sc3+ sites. In addition to 1.45–1.58 μm photons directly absorbed by the Er3+ ions, we have demonstrated upconversion of 1.1–1.35 μm photons in the Ni2+ absorption band to 0.98 μm photons, using 10% Er, 0.5% Ni, and 0.5% Nb-doped La(Ga0.5Sc0.5)O3. The broadband-sensitive upconverter developed here can improve conversion efficiency of crystalline silicon solar cells more notably than conventional ones

  18. Establishment of cell surface engineering and its development.

    Science.gov (United States)

    Ueda, Mitsuyoshi

    2016-07-01

    Cell surface display of proteins/peptides has been established based on mechanisms of localizing proteins to the cell surface. In contrast to conventional intracellular and extracellular (secretion) expression systems, this method, generally called an arming technology, is particularly effective when using yeasts as a host, because the control of protein folding that is often required for the preparation of proteins can be natural. This technology can be employed for basic and applied research purposes. In this review, I describe various strategies for the construction of engineered yeasts and provide an outline of the diverse applications of this technology to industrial processes such as the production of biofuels and chemicals, as well as bioremediation and health-related processes. Furthermore, this technology is suitable for novel protein engineering and directed evolution through high-throughput screening, because proteins/peptides displayed on the cell surface can be directly analyzed using intact cells without concentration and purification. Functional proteins/peptides with improved or novel functions can be created using this beneficial, powerful, and promising technique. PMID:27305282

  19. Broadband grating couplers for efficient thin film solar cells. Final report; Breitband-Gitterkoppler fuer effiziente Duennschichtsolarzellen. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Stutzmann, M.; Nebel, C.E.; Eisele, C.; Klein, S.; Carius, R.; Finger, F.; Schubert, M.

    2002-08-01

    Efficient thin film solar cells usually require a dedicated light trapping strategy in order to achieve an optimum absorption of the solar spectrum. At present, mainly statistically textured transparent conducting electrodes are used for this purpose (TCO layers, e.g. ZnO). One aim of this project was the preparation and characterization of microstructured periodic grating couplers for the efficient trapping of weakly absorbed light in silicon thin film cells. In addition, a preliminary investigation concerning the feasibility of thin SiGe-alloy films on glass as an alternative absorber layer for tandem solar cells was to be performed. Periodically structured TCO electrodes were prepared by holographic laser patterning. These electrode layers are transparent up to the UV spectral range and can be easily structured into sub-micron gratings using HCl etching. In cooperation with the Institute for Photovoltaics (IPV), the resulting light trapping structures were overgrown by amorphous silicon solar cells using PECVD. The electrical and optical properties of these solar cells with integrated grating couplers were investigated in a systematic way, with special emphasis on the possible enhancement of the internal electric field caused by the microstructure. In addition, the growth of amorphous and microcrystalline silicon solar cell structures by hot wire CVD on both, structured as well as unstructured substrates was studied at the IPV. A second part of the project was concerned with the deposition of ultrapure amorphous Si, SiGe, and Ge films on glass by evaporation in an ultra high vacuum, followed by laser recrystallization and hydrogen passivation. For this purpose, a dedicated UHV deposition system was built. The deposited films were recrystallized with a variety of different laser techniques in order to achieve a first optimization of crystallite sizes and electronic properties. Main results of the project: (i) Grating couplers indeed can provide an efficient and

  20. Toward Synthetic Spatial Patterns in Engineered Cell Populations with Chemotaxis.

    Science.gov (United States)

    Duran-Nebreda, Salva; Solé, Ricard V

    2016-07-15

    A major force shaping form and patterns in biology is based in the presence of amplification mechanisms able to generate ordered, large-scale spatial structures out of local interactions and random initial conditions. Turing patterns are one of the best known candidates for such ordering dynamics, and their existence has been proven in both chemical and physical systems. Their relevance in biology, although strongly supported by indirect evidence, is still under discussion. Extensive modeling approaches have stemmed from Turing's pioneering ideas, but further confirmation from experimental biology is required. An alternative possibility is to engineer cells so that self-organized patterns emerge from local communication. Here we propose a potential synthetic design based on the interaction between population density and a diffusing signal, including also directed motion in the form of chemotaxis. The feasibility of engineering such a system and its implications for developmental biology are also assessed. PMID:27009520

  1. Epidermal stem cells and skin tissue engineering in hairfollicle regeneration

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    The reconstitution of a fully organized and functionalhair follicle from dissociated cells propagated underdefined tissue culture conditions is a challenge stillpending in tissue engineering. The loss of hair folliclescaused by injuries or pathologies such as alopecia notonly affects the patients' psychological well-being, butalso endangers certain inherent functions of the skin. Itis then of great interest to find different strategies aimingto regenerate or neogenerate the hair follicle underconditions proper of an adult individual. Based uponcurrent knowledge on the epithelial and dermal cells andtheir interactions during the embryonic hair generationand adult hair cycling, many researchers have tried toobtain mature hair follicles using different strategies andapproaches depending on the causes of hair loss. Thisreview summarizes current advances in the differentexperimental strategies to regenerate or neogenerate hairfollicles, with emphasis on those involving neogenesisof hair follicles in adult individuals using isolated cellsand tissue engineering. Most of these experiments wereperformed using rodent cells, particularly from embryonicor newborn origin. However, no successful strategy togenerate human hair follicles from adult cells has yetbeen reported. This review identifies several issues thatshould be considered to achieve this objective. Perhapsthe most important challenge is to provide threedimensionalculture conditionsmimicking the structure ofliving tissue. Improving culture conditions that allow theexpansion of specific cells while protecting their inductiveproperties, as well as methods for selecting populationsof epithelial stem cells, should give us the necessary toolsto overcome the difficulties that constrain human hairfollicle neogenesis. An analysis of patent trends showsthat the number of patent applications aimed at hairfollicle regeneration and neogenesis has been increasingduring the last decade. This field is attractive not only

  2. Fabrication of a thermoresponsive cell culture dish: a key technology for cell sheet tissue engineering

    OpenAIRE

    Jun Kobayashi and Teruo Okano

    2010-01-01

    This article reviews the properties and characterization of an intelligent thermoresponsive surface, which is a key technology for cell sheet-based tissue engineering. Intelligent thermoresponsive surfaces grafted with poly(N-isopropylacrylamide) exhibit hydrophilic/hydrophobic alteration in response to temperature change. Cultured cells are harvested on thermoresponsive cell culture dishes by decreasing the temperature without the use of digestive enzymes or chelating agents. Our group has d...

  3. Reverse engineering human neurodegenerative disease using pluripotent stem cell technology.

    Science.gov (United States)

    Liu, Ying; Deng, Wenbin

    2016-05-01

    With the technology of reprogramming somatic cells by introducing defined transcription factors that enables the generation of "induced pluripotent stem cells (iPSCs)" with pluripotency comparable to that of embryonic stem cells (ESCs), it has become possible to use this technology to produce various cells and tissues that have been difficult to obtain from living bodies. This advancement is bringing forth rapid progress in iPSC-based disease modeling, drug screening, and regenerative medicine. More and more studies have demonstrated that phenotypes of adult-onset neurodegenerative disorders could be rather faithfully recapitulated in iPSC-derived neural cell cultures. Moreover, despite the adult-onset nature of the diseases, pathogenic phenotypes and cellular abnormalities often exist in early developmental stages, providing new "windows of opportunity" for understanding mechanisms underlying neurodegenerative disorders and for discovering new medicines. The cell reprogramming technology enables a reverse engineering approach for modeling the cellular degenerative phenotypes of a wide range of human disorders. An excellent example is the study of the human neurodegenerative disease amyotrophic lateral sclerosis (ALS) using iPSCs. ALS is a progressive neurodegenerative disease characterized by the loss of upper and lower motor neurons (MNs), culminating in muscle wasting and death from respiratory failure. The iPSC approach provides innovative cell culture platforms to serve as ALS patient-derived model systems. Researchers have converted iPSCs derived from ALS patients into MNs and various types of glial cells, all of which are involved in ALS, to study the disease. The iPSC technology could be used to determine the role of specific genetic factors to track down what׳s wrong in the neurodegenerative disease process in the "disease-in-a-dish" model. Meanwhile, parallel experiments of targeting the same specific genes in human ESCs could also be performed to

  4. Direct fired reciprocating engine and bottoming high temperature fuel cell hybrid

    Science.gov (United States)

    Geisbrecht, Rodney A.; Holcombe, Norman T.

    2006-02-07

    A system of a fuel cell bottoming an internal combustion engine. The engine exhaust gas may be combined in varying degrees with air and fed as input to a fuel cell. Reformer and oxidizers may be combined with heat exchangers to accommodate rich and lean burn conditions in the engine in peaking and base load conditions without producing high concentrations of harmful emissions.

  5. Broadband terahertz spectroscopy

    Institute of Scientific and Technical Information of China (English)

    Wenhui Fan

    2011-01-01

    1.Introduction Spanning the frequency range between the infrared (IR) radiation and microwaves,terahertz (THz) waves are,also known as T-rays,T-lux,or simply called THz,assigned to cover the electromagnetic spectrum typically from 100 GHz (1011 Hz) to 10 THz (1013 Hz),namely,from 3 mm to 30 μm in wavelength,although slightly different definitions have been quoted by different authors.For a very long time,THz region is an almost unexplored field due to its rather unique location in the electromagnetic spectrum.Well-known techniques in optical or microwave region can not be directly employed in the THz range because optical wavelengths are too short and microwave wavelengths are too long compared to THz wavelengths.%An overview of the major techniques to generate and detect THz radiation so far, especially the major approaches to generate and detect coherent ultra-short THz pulses using ultra-short pulsed laser, has been presented. And also, this paper, in particularly, focuses on broadband THz spectroscopy and addresses on a number of issues relevant to generation and detection of broadband pulsed THz radiation as well as broadband time-domain THz spectroscopy (THz-TDS) with the help of ultra-short pulsed laser. The time-domain waveforms of coherent ultra-short THz pulses from photoconductive antenna excited by femtosecond laser with different pulse durations and their corresponding Fourier-transformed spectra have been obtained via the numerical simulation of ultrafast dynamics between femtosecond laser pulse and photoconductive material. The origins of fringes modulated on the top of broadband amplitude spectrum, which is measured by electric-optic detector based on thin nonlinear crystal and extracted by fast Fourier transformation, have been analyzed and the major solutions to get rid of these fringes are discussed.

  6. Human dental pulp stem cell is a promising autologous seed cell for bone tissue engineering

    Institute of Scientific and Technical Information of China (English)

    LI Jing-hui; LIU Da-yong; ZHANG Fang-ming; WANG Fan; ZHANG Wen-kui; ZHANG Zhen-ting

    2011-01-01

    Background The seed cell is a core problem in bone tissue engineering research.Recent research indicates that human dental pulp stem cells (hDPSCs) can differentiate into osteoblasts in vitro,which suggests that they may become a new kind of seed cells for bone tissue engineering.The aim of this study was to evaluate the osteogenic differentiation of hDPSCs in vitro and bone-like tissue formation when transplanted with three-dimensional gelatin scaffolds in vivo,and hDPSCs may become appropriate seed cells for bone tissue engineering.Methods We have utilized enzymatic digestion to obtain hDPSCs from dental pulp tissue extracted during orthodontic treatment.After culturing and expansion to three passages,the cells were seeded in 6-well plates or on three-dimensional gelatin scaffolds and cultured in osteogenic medium.After 14 days in culture,the three-dimensional gelatin scaffolds were implanted subcutaneously in nude mice for 4 weeks.In 6-well plate culture,osteogenesis was assessed by alkaline phosphatase staining,Von Kossa staining,and reverse transcription-polymerase chain reaction (RT-PCR) analysis of the osteogenesis-specific genes type I collagen (COL l),bone sialoprotein (BSP),osteocalcin (OCN),RUNX2,and osterix (OSX).In three-dimensional gelatin scaffold culture,X-rays,hematoxylin/eosin staining,and immunohistochemical staining were used to examine bone formation.Results In vitro studies revealed that hDPSCs do possess osteogenic differentiation potential.In vivo studies revealed that hDPSCs seeded on gelatin scaffolds can form bone structures in heterotopic sites of nude mice.Conclusions These findings suggested that hDPSCs may be valuable as seed cells for bone tissue engineering.As a special stem cell source,hDPSCs may blaze a new path for bone tissue engineering.

  7. Multifunctional Fullerene Derivative for Interface Engineering in Perovskite Solar Cells.

    Science.gov (United States)

    Li, Yaowen; Zhao, Yue; Chen, Qi; Yang, Yang Michael; Liu, Yongsheng; Hong, Ziruo; Liu, Zonghao; Hsieh, Yao-Tsung; Meng, Lei; Li, Yongfang; Yang, Yang

    2015-12-16

    In perovskite based planar heterojunction solar cells, the interface between the TiO2 compact layer and the perovskite film is critical for high photovoltaic performance. The deep trap states on the TiO2 surface induce several challenging issues, such as charge recombination loss and poor stability etc. To solve the problems, we synthesized a triblock fullerene derivative (PCBB-2CN-2C8) via rational molecular design for interface engineering in the perovskite solar cells. Modifying the TiO2 surface with the compound significantly improves charge extraction from the perovskite layer. Together with its uplifted surface work function, open circuit voltage and fill factor are dramatically increased from 0.99 to 1.06 V, and from 72.2% to 79.1%, respectively, resulting in 20.7% improvement in power conversion efficiency for the best performing devices. Scrutinizing the electrical properties of this modified interfacial layer strongly suggests that PCBB-2CN-2C8 passivates the TiO2 surface and thus reduces charge recombination loss caused by the deep trap states of TiO2. The passivation effect is further proven by stability testing of the perovskite solar cells with shelf lifetime under ambient conditions improved by a factor of more than 4, from ∼40 h to ∼200 h, using PCBB-2CN-2C8 as the TiO2 modification layer. This work offers not only a promising material for cathode interface engineering, but also provides a viable approach to address the challenges of deep trap states on TiO2 surface in planar perovskite solar cells. PMID:26592525

  8. Metabolically Engineered Fungal Cells With Increased Content Of Polyunsaturated Fatty Acids

    DEFF Research Database (Denmark)

    2008-01-01

    This invention relates to the production of fatty acids and particularly to the production of the polyunsaturated fatty acids (PUFAs) arachidonic acid (ARA) and eicosapentaenoic acid (EPA) in genetically engineered fungal cells, in particular, to metabolically engineered Saccharomyces cerevisiae...

  9. Engineering Cell Instructive Materials To Control Cell Fate and Functions through Material Cues and Surface Patterning.

    Science.gov (United States)

    Ventre, Maurizio; Netti, Paolo A

    2016-06-22

    Mastering the interaction between cells and extracellular environment is a fundamental prerequisite in order to engineer functional biomaterial interfaces able to instruct cells with specific commands. Such advanced biomaterials might find relevant application in prosthesis design, tissue engineering, diagnostics and stem cell biology. Because of the highly complex, dynamic, and multifaceted context, a thorough understanding of the cell-material crosstalk has not been achieved yet; however, a variety of material features including biological cues, topography, and mechanical properties have been proved to impact the strength and the nature of the cell-material interaction, eventually affecting cell fate and functions. Although the nature of these three signals may appear very different, they are equated by their participation in the same material-cytoskeleton crosstalk pathway as they regulate cell adhesion events. In this work we present recent and relevant findings on the material-induced cell responses, with a particular emphasis on how the presentation of biochemical/biophysical signals modulates cell behavior. Finally, we summarize and discuss the literature data to draw out unifying elements concerning cell recognition of and reaction to signals displayed by material surfaces. PMID:26693600

  10. Broad-band acoustic hyperbolic metamaterial

    CERN Document Server

    Shen, Chen; Sui, Ni; Wang, Wenqi; Cummer, Steven A; Jing, Yun

    2015-01-01

    Acoustic metamaterials (AMMs) are engineered materials, made from subwavelength structures, that exhibit useful or unusual constitutive properties. There has been intense research interest in AMMs since its first realization in 2000 by Liu et al. A number of functionalities and applications have been proposed and achieved using AMMs. Hyperbolic metamaterials are one of the most important types of metamaterials due to their extreme anisotropy and numerous possible applications, including negative refraction, backward waves, spatial filtering, and subwavelength imaging. Although the importance of acoustic hyperbolic metamaterials (AHMMs) as a tool for achieving full control of acoustic waves is substantial, the realization of a broad-band and truly hyperbolic AMM has not been reported so far. Here, we demonstrate the design and experimental characterization of a broadband AHMM that operates between 1.0 kHz and 2.5 kHz.

  11. Broadband Radio Service (BRS) and Educational Broadband Service (EBS) Transmitters

    Data.gov (United States)

    Department of Homeland Security — The Broadband Radio Service (BRS), formerly known as the Multipoint Distribution Service (MDS)/Multichannel Multipoint Distribution Service (MMDS), is a commercial...

  12. Engineering antigen-specific T cells from genetically modified human hematopoietic stem cells in immunodeficient mice.

    Directory of Open Access Journals (Sweden)

    Scott G Kitchen

    Full Text Available There is a desperate need for effective therapies to fight chronic viral infections. The immune response is normally fastidious at controlling the majority of viral infections and a therapeutic strategy aimed at reestablishing immune control represents a potentially powerful approach towards treating persistent viral infections. We examined the potential of genetically programming human hematopoietic stem cells to generate mature CD8+ cytotoxic T lymphocytes that express a molecularly cloned, "transgenic" human anti-HIV T cell receptor (TCR. Anti-HIV TCR transduction of human hematopoietic stem cells directed the maturation of a large population of polyfunctional, HIV-specific CD8+ cells capable of recognizing and killing viral antigen-presenting cells. Thus, through this proof-of-concept we propose that genetic engineering of human hematopoietic stem cells will allow the tailoring of effector T cell responses to fight HIV infection or other diseases that are characterized by the loss of immune control.

  13. Broadband frequency conversion

    DEFF Research Database (Denmark)

    Sanders, Nicolai; Jensen, Ole Bjarlin; Tidemand-Lichtenberg, Peter;

    We present a simple, passive and static setup for broadband frequency conversion. By using simple optical components like lenses, mirrors and gratings, we obtain the spectral angular dispersion to match the second harmonic generation phasematching angles in a nonlinear BiBO crystal. We are able to...... frequency double a single-frequency diode laser, tunable in the 1020-1090 nm range, with almost equal efficiency for all wavelengths. In the experimental setup, the width of the phasematch was increased with a factor of 50. The method can easily be extended to other wavelength ranges and nonlinear crystals...

  14. Stem cell bioprocess engineering towards cGMP production and clinical applications

    OpenAIRE

    Sart, Sébastien; Schneider, Yves-Jacques; Li, Yan; Agathos, Spiros N.

    2014-01-01

    Stem cells, including mesenchymal stem cells and pluripotent stem cells, are becoming an indispensable tool for various biomedical applications including drug discovery, disease modeling, and tissue engineering. Bioprocess engineering, targeting large scale production, provides a platform to generate a controlled microenvironment that could potentially recreate the stem cell niche to promote stem cell proliferation or lineage-specific differentiation. This survey aims at defining the characte...

  15. Genetic engineering of platelets to neutralize circulating tumor cells.

    Science.gov (United States)

    Li, Jiahe; Sharkey, Charles C; Wun, Brittany; Liesveld, Jane L; King, Michael R

    2016-04-28

    Mounting experimental evidence demonstrates that platelets support cancer metastasis. Within the circulatory system, platelets guard circulating tumor cells (CTCs) from immune elimination and promote their arrest at the endothelium, supporting CTC extravasation into secondary sites. Neutralization of CTCs in blood circulation can potentially attenuate metastases to distant organs. Therefore, extensive studies have explored the blockade of platelet-CTC interactions as an anti-metastatic strategy. Such an intervention approach, however, may cause bleeding disorders since the platelet-CTC interactions inherently rely on the blood coagulation cascade including platelet activation. On the other hand, platelets have been genetically engineered to correct inherited bleeding disorders in both animal models and human clinical trials. In this study, inspired by the physical association between platelets and CTCs, platelets were genetically modified to express surface-bound tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), a cytokine known to induce apoptosis specifically in tumor cells. The TRAIL-expressing platelets were demonstrated to kill cancer cells in vitro and significantly reduce metastases in a mouse model of prostate cancer metastasis. Our results suggest that using platelets to produce and deliver cancer-specific therapeutics can provide a Trojan-horse strategy of neutralizing CTCs to attenuate metastasis. PMID:26921521

  16. A blueprint for engineering cell fate: current technologies to reprogram cell identity

    Institute of Scientific and Technical Information of China (English)

    Samantha A Morris; George Q Daley

    2013-01-01

    Human diseases such as heart failure,diabetes,neurodegenerative disorders,and many others result from the deficiency or dysfunction of critical cell types.Strategies for therapeutic tissue repair or regeneration require the in vitro manufacture of clinically relevant quantities of defined cell types.In addition to transplantation therapy,the generation of otherwise inaccessible cells also permits disease modeling,toxicology testing and drug discovery in vitro.In this review,we discuss current strategies to manipulate the identity of abundant and accessible cells by differentiation from an induced pluripotent state or direct conversion between differentiated states.We contrast these approaches with recent advances employing partial reprogramming to facilitate lineage switching,and discuss the mechanisms underlying the engineering of cell fate.Finally,we address the current limitations of the field and how the resulting cell types can be assessed to ensure the production of medically relevant populations.

  17. Broadband near-infrared quantum-cutting by cooperative energy transfer in Yb3+–Bi3+ co-doped CaTiO3 for solar cells

    International Nuclear Information System (INIS)

    Highlights: • Broadband NIR QC CaTiO3:Yb3+,Bi3+ phosphor has been firstly developed. • Co-doping with Bi3+, it enhanced the Yb3+ emission intensity by a factor of 10. • This phosphor could efficiently convert 300–480 nm light to ∼1000 nm light. • The ET processes were involved in CET via two photons QC process. - Abstract: An efficient near-infrared (NIR) quantum-cutting (QC) process which converts broadband ultraviolet-blue into NIR via downconversion (DC) has been demonstrated in CaTiO3:Yb3+,Bi3+ phosphors for the first time. These phosphors are valuable for use in crystalline Si (c-Si) solar cells, because they efficiently convert 300–480 nm light that is not fully utilized by existing c-Si solar cells into ∼1000 nm NIR light that can be sufficiently absorbed by solar cells. Co-doping with 15% Bi3+ ions, a significant enhancement in Yb3+ NIR integrated emission intensity by a factor of 10 is realized. The phosphors were characterized with the photoluminescence excitation (PLE) and the photoluminescence (PL) spectra evidence the presence of energy transfer (ET) processes from Bi3+-related charge transfer state to Yb3+ ions. The dependence of Yb3+ luminescent intensity on the excitation power was also measured and it demonstrates that the ET processes involve cooperative energy transfer (CET) via two photons QC processes

  18. Process engineering of ceramic composite coatings for fuel cell systems

    Energy Technology Data Exchange (ETDEWEB)

    Li, G.; Kim, H.; Chen, M.; Yang, Q.; Troczynski, T. [British Columbia Univ., Vancouver, BC (Canada). Dept. of Metals and Materials Engineering

    2003-07-01

    Researchers at UBCeram at the Department of Metals and Materials Engineering at the University of British Columbia have developed a technology to chemically bond composite sol-gel (CB-CSG) coating onto metallic surfaces of complex or concave shapes. The process has been optimized for electrically resistive coatings and corrosion-resistant coatings. The CSG is sprayed onto metallic surfaces and is heat-treated at 300 degrees C to partially dehydrate the hydroxides. The CSG film is then chemically bonded through reaction of active alumina with metal phosphates, such as aluminium phosphate. A new chromate-free process is being developed to address the issue of coatings porosity. The electrodeposition technique involves polymer particles mixed with suspended fine alumina particles which are co-deposited by electrophoretic means or by electrocoagulation. The composite e-coatings have excellent mechanical properties and are being considered as a protective coating for various components of fuel cell systems. 9 refs., 7 figs.

  19. Broadband pendulum energy harvester

    Science.gov (United States)

    Liang, Changwei; Wu, You; Zuo, Lei

    2016-09-01

    A novel electromagnetic pendulum energy harvester with mechanical motion rectifier (MMR) is proposed and investigated in this paper. MMR is a mechanism which rectifies the bidirectional swing motion of the pendulum into unidirectional rotation of the generator by using two one-way clutches in the gear system. In this paper, two prototypes of pendulum energy harvester with MMR and without MMR are designed and fabricated. The dynamic model of the proposed MMR pendulum energy harvester is established by considering the engagement and disengagement of the one way clutches. The simulation results show that the proposed MMR pendulum energy harvester has a larger output power at high frequencies comparing with non-MMR pendulum energy harvester which benefits from the disengagement of one-way clutch during pendulum vibration. Moreover, the proposed MMR pendulum energy harvester is broadband compare with non-MMR pendulum energy harvester, especially when the equivalent inertia is large. An experiment is also conducted to compare the energy harvesting performance of these two prototypes. A flywheel is attached at the end of the generator to make the disengagement more significant. The experiment results also verify that MMR pendulum energy harvester is broadband and has a larger output power at high frequency over the non-MMR pendulum energy harvester.

  20. Internalisation of engineered nanoparticles into mammalian cells in vitro: influence of cell type and particle properties

    International Nuclear Information System (INIS)

    Cellular internalisation of industrial engineered nanoparticles is undesired and a reason for concern. Here we investigated and compared the ability of seven different mammalian cell cultures in vitro to incorporate six kinds of engineered nanoparticles, focussing on the role of cell type and particle properties in particle uptake. Uptake was examined using light and electron microscopy coupled with energy dispersive X-ray spectroscopy (EDX) for particle element identification. Flow cytometry was applied for semi-quantitative analyses of particle uptake and for exploring the influence on uptake by the phagocytosis inhibitor Cytochalasin D (CytoD). All particles studied were found to enter each kind of cultured cells. Yet, particles were never found within cell nuclei. The presence of the respective particles within the cells was confirmed by EDX. Live-cell imaging revealed the time-dependent process of internalisation of technical nanoparticles, which was exemplified by tungsten carbide particle uptake into the human skin cells, HaCaT. Particles were found to co-localise with lysosomal structures within the cells. The incorporated nanoparticles changed the cellular granularity, as measured by flow cytometry, already after 3 h of exposure in a particle specific manner. By correlating particle properties with flow cytometry data, only the primary particle size was found to be a weakly influential property for particle uptake. CytoD, an inhibitor of actin filaments and therewith of phagocytosis, significantly inhibited the internalisation of particle uptake in only two of the seven investigated cell cultures. Our study, therefore, supports the notion that nanoparticles can enter mammalian cells quickly and easily, irrespective of the phagocytic ability of the cells.

  1. Broadband terahertz fiber directional coupler

    DEFF Research Database (Denmark)

    Nielsen, Kristian; Rasmussen, Henrik K.; Jepsen, Peter Uhd; Bang, Ole

    2010-01-01

    We present the design of a short broadband fiber directional coupler for terahertz (THz) radiation and demonstrate a 3 dB coupler with a bandwidth of 0:6 THz centered at 1:4 THz. The broadband coupling is achieved by mechanically downdoping the cores of a dual-core photonic crystal fiber by...

  2. Engineered antifouling microtopographies: surface pattern effects on cell distribution.

    Science.gov (United States)

    Decker, Joseph T; Sheats, Julian T; Brennan, Anthony B

    2014-12-23

    Microtopography has been observed to lead to altered attachment behavior for marine fouling organisms; however, quantification of this phenomenon is lacking in the scientific literature. Here, we present quantitative measurement of the disruption of normal attachment behavior of the fouling algae Ulva linza by antifouling microtopographies. The distribution of the diatom Navicula incerta was shown to be unaffected by the presence of topography. The radial distribution function was calculated for both individual zoospores and cells as well as aggregates of zoospores from attachment data for a variety topographic configurations and at a number of different attachment densities. Additionally, the screening distance and maximum values were mapped according to the location of zoospore aggregates within a single unit cell. We found that engineered topographies decreased the distance between spore aggregates compared to that for a smooth control surface; however, the distributions for individual spores were unchanged. We also found that the local attachment site geometry affected the screening distance for aggregates of zoospores, with certain geometries decreasing screening distance and others having no measurable effect. The distribution mapping techniques developed and explored in this article have yielded important insight into the design parameters for antifouling microtopographies that can be implemented in the next generation of antifouling surfaces. PMID:25420235

  3. Switched Broadband Services For The Home

    Science.gov (United States)

    Sawyer, Don M.

    1990-01-01

    In considering the deployment of fiber optics to the residence, two critical questions arise: what are the leading services that could be offered to justify the required investment; and what is the nature of the business that would offer these services to the consumer ? This talk will address these two questions together with the related issue of how the "financial engine" of today's television distribution infrastructure - TV advertising - would be affected by an open access system based on fiber optics coupled with broadband switching. On the business side, the talk concludes that the potential for open ended capacity expansion, fair competition between service providers, and new interactive services inherent in an open access, switched broadband system are the critical items in differentiating it from existing video and TV distribution systems. On the question of broadband services, the talk will highlight several new opportunities together with some findings from recent market research conducted by BNR. The talk will show that there are variations on existing services plus many new services that could be offered and which have real consumer appeal. The postulated open access system discussed here is visualized as having ultimately 1,000 to 2,000 video channels available to the consumer. Although this may appear to hopelessly fragment the TV audience and destroy the current TV advertising infrastructure, the technology of open access, switched broadband will present many new advertising techniques, which have the potential to be far more effective than those available today. Some of these techniques will be described in this talk.

  4. Polyacylurethanes as Novel Degradable Cell Carrier Materials for Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Arend Jan Schouten

    2011-10-01

    Full Text Available Polycaprolactone (PCL polyester and segmented aliphatic polyester urethanes based on PCL soft segment have been thoroughly investigated as biodegradable scaffolds for tissue engineering. Although proven beneficial as long term implants, these materials degrade very slowly and are therefore not suitable in applications in which scaffold support is needed for a shorter time. A recently developed class of polyacylurethanes (PAUs is expected to fulfill such requirements. Our aim was to assess in vitro the degradation of PAUs and evaluate their suitability as temporary scaffold materials to support soft tissue repair. With both a mass loss of 2.5–3.0% and a decrease in molar mass of approx. 35% over a period of 80 days, PAUs were shown to degrade via both bulk and surface erosion mechanisms. Fourier Transform Infra Red (FTIR spectroscopy was successfully applied to study the extent of PAUs microphase separation during in vitro degradation. The microphase separated morphology of PAU1000 (molar mass of the oligocaprolactone soft segment = 1000 g/mol provided this polymer with mechano-physical characteristics that would render it a suitable material for constructs and devices. PAU1000 exhibited excellent haemocompatibility in vitro. In addition, PAU1000 supported both adhesion and proliferation of vascular endothelial cells and this could be further enhanced by pre-coating of PAU1000 with fibronectin (Fn. The contact angle of PAU1000 decreased both with in vitro degradation and by incubation in biological fluids. In endothelial cell culture medium the contact angle reached 60°, which is optimal for cell adhesion. Taken together, these results support the application of PAU1000 in the field of soft tissue repair as a temporary degradable scaffold.

  5. Metamaterial broadband angular selectivity

    Science.gov (United States)

    Shen, Yichen; Ye, Dexin; Wang, Li; Celanovic, Ivan; Ran, Lixin; Joannopoulos, John D.; Soljačić, Marin

    2014-09-01

    We demonstrate how broadband angular selectivity can be achieved with stacks of one-dimensionally periodic photonic crystals, each consisting of alternating isotropic layers and effective anisotropic layers, where each effective anisotropic layer is constructed from a multilayered metamaterial. We show that by simply changing the structure of the metamaterials, the selective angle can be tuned to a broad range of angles; and, by increasing the number of stacks, the angular transmission window can be made as narrow as desired. As a proof of principle, we realize the idea experimentally in the microwave regime. The angular selectivity and tunability we report here can have various applications such as in directional control of electromagnetic emitters and detectors.

  6. Metamaterial Broadband Angular Selectivity

    CERN Document Server

    Shen, Yichen; Wang, Zhiyu; Wang, Li; Celanovic, Ivan; Ran, Lixin; Joannopoulos, John D; Soljacic, Marin

    2014-01-01

    We demonstrate how broadband angular selectivity can be achieved with stacks of one-dimensionally periodic photonic crystals, each consisting of alternating isotropic layers and effective anisotropic layers, where each effective anisotropic layer is constructed from a multilayered metamaterial. We show that by simply changing the structure of the metamaterials, the selective angle can be tuned to a broad range of angles; and, by increasing the number of stacks, the angular transmission window can be made as narrow as desired. As a proof of principle, we realize the idea experimentally in the microwave regime. The angular selectivity and tunability we report here can have various applications such as in directional control of electromagnetic emitters and detectors.

  7. Stem Cells and Progenitor Cells for Tissue-Engineered Solutions to Congenital Heart Defects

    OpenAIRE

    Yang Gao; Jacot, Jeffrey G.

    2015-01-01

    Synthetic patches and fixed grafts currently used in the repair of congenital heart defects are nonliving, noncontractile, and not electrically responsive, leading to increased risk of complication, reoperation, and sudden cardiac death. Studies suggest that tissue-engineered patches made from living, functional cells could grow with the patient, facilitate healing, and help recover cardiac function. In this paper, we review the research into possible sources of cardiomyocytes and other cardi...

  8. The Effects of Environmental Factors on Smooth Muscle Cells Differentiation from Adipose-Derived Stem Cells and Esophagus Tissues Engineering

    OpenAIRE

    Wang, Fang

    2015-01-01

    Adipose-derived stem cells (ASCs) are increasingly being used for regenerative medicine and tissue engineering. Smooth muscle cells (SMCs) can be differentiated from ASCs. Oxygen is a key factor influencing the stem cell differentiation. Tissue engineered esophagus has been a preferred solution for diseased esophagus replacement. The first part involved the effect of hypoxia on differentiation. The results showed 5% hypoxia to be the optimal condition for differentiation of ASCs into contract...

  9. Broadband and ultra-broadband modular half-wave plates

    Science.gov (United States)

    Dimova, Emiliya; Huang, Wei; Popkirov, George; Rangelov, Andon; Kyoseva, Elica

    2016-05-01

    We experimentally demonstrate broadband and ultra-broadband spectral bandwidth modular half-wave plates. Both modular devices comprise an array of rotated single half-wave plates (HWPs), whereby for broadband and ultra-broadband performance we use standard and commercial achromatic HWPs, respectively. The bandwidth of the modular HWPs depends on the number N of individual HWPs used and in this paper we experimentally investigate this for N = { 3 , 5 , 7 , 9 }. The elements in the arrays are rotated at specific angles with respect to their fast-polarization axes, independent of the nature of the birefringent material. We find the rotation angles using an analogy to the technique of composite pulses, which is widely used for control in nuclear magnetic resonance.

  10. CRISPR-Cas9 Genome Engineering in Saccharomyces cerevisiae Cells.

    Science.gov (United States)

    Ryan, Owen W; Poddar, Snigdha; Cate, Jamie H D

    2016-01-01

    This protocol describes a method for CRISPR-Cas9-mediated genome editing that results in scarless and marker-free integrations of DNA into Saccharomyces cerevisiae genomes. DNA integration results from cotransforming (1) a single plasmid (pCAS) that coexpresses the Cas9 endonuclease and a uniquely engineered single guide RNA (sgRNA) expression cassette and (2) a linear DNA molecule that is used to repair the chromosomal DNA damage by homology-directed repair. For target specificity, the pCAS plasmid requires only a single cloning modification: replacing the 20-bp guide RNA sequence within the sgRNA cassette. This CRISPR-Cas9 protocol includes methods for (1) cloning the unique target sequence into pCAS, (2) assembly of the double-stranded DNA repair oligonucleotides, and (3) cotransformation of pCAS and linear repair DNA into yeast cells. The protocol is technically facile and requires no special equipment. It can be used in any S. cerevisiae strain, including industrial polyploid isolates. Therefore, this CRISPR-Cas9-based DNA integration protocol is achievable by virtually any yeast genetics and molecular biology laboratory. PMID:27250940

  11. Sensitive, time-resolved, broadband spectroscopy of single transient processes

    Science.gov (United States)

    Fjodorow, Peter; Baev, Ivan; Hellmig, Ortwin; Sengstock, Klaus; Baev, Valery M.

    2015-09-01

    Intracavity absorption spectroscopy with a broadband Er3+-doped fiber laser is applied to time-resolved measurements of transient gain and absorption in electrically excited Xe and Kr plasmas. The achieved time resolution for broadband spectral recording of a single process is 25 µs. For pulsed-periodic processes, the time resolution is limited by the laser pulse duration, which is set here to 3 µs. This pulse duration also predefines the effective absorption path length, which amounts to 900 m. The presented technique can be applied to multicomponent analysis of single transient processes such as shock tube experiments, pulse detonation engines, or explosives.

  12. Broadband development in the Czech and Slovak Republics

    Czech Academy of Sciences Publication Activity Database

    Kuchar, Anton; Hrstka, J.; Murín, V.

    Vol. E8. Geneve : BReATH Consortium, 2006, --. [BReATH Closing Conference. Geneve (CH), 11.12.2006] Grant ostatní: BReATH Consortium EU(XE) EC FP6 1ST Programme Institutional research plan: CEZ:AV0Z20670512 Keywords : Internet * telecommunication networks * broadband networks Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering http://www.ist-breath.net/documents/BReATH/E8_Closing_Conference/presentations/session_II/Kuchar_-_Broadband_development_in_CZ_and_SR.pdf

  13. CRISPR/Cas9 advances engineering of microbial cell factories

    DEFF Research Database (Denmark)

    Jakociunas, Tadas; Jensen, Michael Krogh; Keasling, Jay D.

    2016-01-01

    interspaced palindromic repeats (CRISPR) and its associated proteins (Cas) have become the method of choice for precision genome engineering in many organisms due to their orthogonality, versatility and efficacy. Here we review the strategies adopted for implementation of RNA-guided CRISPR/Cas9 genome editing...... be highlighted. Finally, this review will provide a perspective on the immediate challenges and opportunities foreseen by the use of CRISPR/Cas9 genome engineering and regulation in the context of metabolic engineering....

  14. Extraction and Assembly of Tissue-Derived Gels for Cell Culture and Tissue Engineering

    OpenAIRE

    Uriel, Shiri; Labay, Edwardine; Francis-Sedlak, Megan; Moya, Monica L.; Weichselbaum, Ralph R.; Ervin, Natalia; Cankova, Zdravka; Eric M Brey

    2008-01-01

    Interactions with the extracellular matrix (ECM) play an important role in regulating cell function. Cells cultured in, or on, three-dimensional ECM recapitulate similar features to those found in vivo that are not present in traditional two-dimensional culture. In addition, both natural and synthetic materials containing ECM components have shown promise in a number of tissue engineering applications. Current materials available for cell culture and tissue engineering do not adequately refle...

  15. Adipose-Derived Stem Cells for Tissue Engineering and Regenerative Medicine Applications

    OpenAIRE

    Ru Dai; Zongjie Wang; Roya Samanipour; Kyo-in Koo; Keekyoung Kim

    2016-01-01

    Adipose-derived stem cells (ASCs) are a mesenchymal stem cell source with properties of self-renewal and multipotential differentiation. Compared to bone marrow-derived stem cells (BMSCs), ASCs can be derived from more sources and are harvested more easily. Three-dimensional (3D) tissue engineering scaffolds are better able to mimic the in vivo cellular microenvironment, which benefits the localization, attachment, proliferation, and differentiation of ASCs. Therefore, tissue-engineered ASCs ...

  16. Broadband Advanced Spectral System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NovaSol proposes to develop an advanced hyperspectral imaging system for earth science missions named BRASS (Broadband Advanced Spectral System). BRASS combines...

  17. Computational model-informed design and bioprinting of cell-patterned constructs for bone tissue engineering.

    Science.gov (United States)

    Carlier, Aurélie; Skvortsov, Gözde Akdeniz; Hafezi, Forough; Ferraris, Eleonora; Patterson, Jennifer; Koç, Bahattin; Van Oosterwyck, Hans

    2016-01-01

    Three-dimensional (3D) bioprinting is a rapidly advancing tissue engineering technology that holds great promise for the regeneration of several tissues, including bone. However, to generate a successful 3D bone tissue engineering construct, additional complexities should be taken into account such as nutrient and oxygen delivery, which is often insufficient after implantation in large bone defects. We propose that a well-designed tissue engineering construct, that is, an implant with a specific spatial pattern of cells in a matrix, will improve the healing outcome. By using a computational model of bone regeneration we show that particular cell patterns in tissue engineering constructs are able to enhance bone regeneration compared to uniform ones. We successfully bioprinted one of the most promising cell-gradient patterns by using cell-laden hydrogels with varying cell densities and observed a high cell viability for three days following the bioprinting process. In summary, we present a novel strategy for the biofabrication of bone tissue engineering constructs by designing cell-gradient patterns based on a computational model of bone regeneration, and successfully bioprinting the chosen design. This integrated approach may increase the success rate of implanted tissue engineering constructs for critical size bone defects and also can find a wider application in the biofabrication of other types of tissue engineering constructs. PMID:27187017

  18. Heterogeneous broadband network

    Science.gov (United States)

    Dittmann, Lars

    1995-11-01

    Although the vision for the future Integrated Broadband Communication Network (IBCN) is an all optical network, it is certain that for a long period to come, the network will remain very heterogeneous, with a mixture of different physical media (fiber, coax and twisted pair), transmission systems (PDH, SDH, ADSL) and transport protocols (TCP/IP, AAL/ATM, frame relay). In the current work towards the IBCN, the ATM concept is considered the generic network protocol for both public and private network, with the ability to use different underlying transmission protocols and, through adaptation protocols, provide the appropriate services (old as well as new) to the customer. One of the major difficulties of heterogeneous network is the restriction that is usually given by the lowest common denominator, e.g. in terms of single channel capacity. A possible way to overcome these limitations is by extending the ATM concept with a multilink capability, that allows us to use separate resources as one common. The improved flexibility obtained by this protocol extension further allows a real time optimization of network and call configuration, without any impact on the quality of service seen from the user. This paper describes an example of an ATM based multilink protocol that has been experimentally implemented within the RACE project 'STRATOSPHERIC'. The paper outlines the complexity of introducing an extra network functionality compared with the added value, such as an improved ability to recover an error due to a malfunctioning network component.

  19. Broadband accelerator control network

    International Nuclear Information System (INIS)

    A broadband data communications network has been implemented at BNL for control of the Alternating Gradient Synchrotron (AG) proton accelerator, using commercial CATV hardware, dual coaxial cables as the communications medium, and spanning 2.0 km. A 4 MHz bandwidth Digital Control channel using CSMA-CA protocol is provided for digital data transmission, with 8 access nodes available over the length of the RELWAY. Each node consists of an rf modem and a microprocessor-based store-and-forward message handler which interfaces the RELWAY to a branch line implemented in GPIB. A gateway to the RELWAY control channel for the (preexisting) AGS Computerized Accelerator Operating system has been constructed using an LSI-11/23 microprocessor as a device in a GPIB branch line. A multilayer communications protocol has been defined for the Digital Control Channel, based on the ISO Open Systems Interconnect layered model, and a RELWAY Device Language defined as the required universal language for device control on this channel

  20. Broadband near-infrared quantum-cutting by cooperative energy transfer in Yb{sup 3+}–Bi{sup 3+} co-doped CaTiO{sub 3} for solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Li-Tian; Chen, Jun-Qiang; Deng, Chao; Tang, Li; Chen, Dong-Ju; Meng, Jian-Xin, E-mail: tmjx@jnu.edu.cn; Cao, Li-Wei

    2015-08-15

    Highlights: • Broadband NIR QC CaTiO{sub 3}:Yb{sup 3+},Bi{sup 3+} phosphor has been firstly developed. • Co-doping with Bi{sup 3+}, it enhanced the Yb{sup 3+} emission intensity by a factor of 10. • This phosphor could efficiently convert 300–480 nm light to ∼1000 nm light. • The ET processes were involved in CET via two photons QC process. - Abstract: An efficient near-infrared (NIR) quantum-cutting (QC) process which converts broadband ultraviolet-blue into NIR via downconversion (DC) has been demonstrated in CaTiO{sub 3}:Yb{sup 3+},Bi{sup 3+} phosphors for the first time. These phosphors are valuable for use in crystalline Si (c-Si) solar cells, because they efficiently convert 300–480 nm light that is not fully utilized by existing c-Si solar cells into ∼1000 nm NIR light that can be sufficiently absorbed by solar cells. Co-doping with 15% Bi{sup 3+} ions, a significant enhancement in Yb{sup 3+} NIR integrated emission intensity by a factor of 10 is realized. The phosphors were characterized with the photoluminescence excitation (PLE) and the photoluminescence (PL) spectra evidence the presence of energy transfer (ET) processes from Bi{sup 3+}-related charge transfer state to Yb{sup 3+} ions. The dependence of Yb{sup 3+} luminescent intensity on the excitation power was also measured and it demonstrates that the ET processes involve cooperative energy transfer (CET) via two photons QC processes.

  1. Monosaccharide-responsive phenylboronate-polyol cell scaffolds for cell sheet and tissue engineering applications.

    Directory of Open Access Journals (Sweden)

    Rachamalla Maheedhar Reddy

    Full Text Available Analyte-responsive smart polymeric materials are of great interest and have been actively investigated in the field of regenerative medicine. Phenylboronate containing copolymers form gels with polyols under alkaline conditions. Monosaccharides, by virtue of their higher affinity towards boronate, can displace polyols and solubilize such gels. In the present study, we investigate the possibility of utilizing phenylboronate-polyol interactions at physiological pH in order to develop monosaccharide-responsive degradable scaffold materials for systems dealing with cells and tissues. Amine assisted phenylboronate-polyol interactions were employed to develop novel hydrogel and cryogel scaffolds at neutral pH. The scaffolds displayed monosaccharide inducible gel-sol phase transformability. In vitro cell culture studies demonstrated the ability of scaffolds to support cell adhesion, viability and proliferation. Fructose induced gel degradation is used to recover cells cultured on the hydrogels. The cryogels displayed open macroporous structure and superior mechanical properties. These novel phase transformable phenylboronate-polyol based scaffolds displayed a great potential for various cell sheet and tissue engineering applications. Their monosaccharide responsiveness at physiological pH is very useful and can be utilized in the fields of cell immobilization, spheroid culture, saccharide recognition and analyte-responsive drug delivery.

  2. Mature adipocytes may be a source of stem cells for tissue engineering

    International Nuclear Information System (INIS)

    Adipose tissue contains a large portion of stem cells. These cells appear morphologically like fibroblasts and are primarily derived from the stromal cell fraction. Mature (lipid-filled) adipocytes possess the ability to become proliferative cells and have been shown to produce progeny cells that possess the same morphological (fibroblast-like) appearance as the stem cells from the stromal fraction. A closer examination of mature adipocyte-derived progeny cells may prove to be an emerging area of growth/metabolic physiology that may modify present thinking about adipose tissue renewal capabilities. Knowledge of these cells may also prove beneficial in cell-based therapies for tissue repair, regeneration, or engineering

  3. Nano-Engineered Catalysts for Direct Methanol Fuel Cells

    Science.gov (United States)

    Myung, Nosang; Narayanan, Sekharipuram; Wiberg, Dean

    2008-01-01

    Nano-engineered catalysts, and a method of fabricating them, have been developed in a continuing effort to improve the performances of direct methanol fuel cells as candidate power sources to supplant primary and secondary batteries in a variety of portable electronic products. In order to realize the potential for high energy densities (as much as 1.5 W h/g) of direct methanol fuel cells, it will be necessary to optimize the chemical compositions and geometric configurations of catalyst layers and electrode structures. High performance can be achieved when catalyst particles and electrode structures have the necessary small feature sizes (typically of the order of nanometers), large surface areas, optimal metal compositions, high porosity, and hydrophobicity. The present method involves electrodeposition of one or more catalytic metal(s) or a catalytic-metal/polytetrafluoroethylene nanocomposite on an alumina nanotemplate. The alumina nanotemplate is then dissolved, leaving the desired metal or metal/polytetrafluoroethylene-composite catalyst layer. Unlike some prior methods of making fine metal catalysts, this method does not involve processing at elevated temperature; all processing can be done at room temperature. In addition, this method involves fewer steps and is more amenable to scaling up for mass production. Alumina nanotemplates are porous alumina membranes that have been fabricated, variously, by anodizing either pure aluminum or aluminum that has been deposited on silicon by electronbeam evaporation. The diameters of the pores (7 to 300 nm), areal densities of pores (as much as 7 x 10(exp 10)sq cm), and lengths of pores (up to about 100 nm) can be tailored by selection of fabrication conditions. In a given case, the catalytic metal, catalytic metal alloy, or catalytic metal/ polytetrafluoroethylene composite is electrodeposited in the pores of the alumina nanotemplate. The dimensions of the pores, together with the electrodeposition conditions

  4. Negative impedance shunted electromagnetic absorber for broadband absorbing: experimental investigation

    International Nuclear Information System (INIS)

    The traditional tuned mass absorber is widely employed to control the vibration of a primary structure by transferring the vibrating energy to the absorber. However, the working band of the absorber is very narrow, which limits the application of broadband vibration control. This study presents a novel broadband electromagnetic absorber by first introducing two negative impedance shunts to improve broadband damping of the absorber. The electromagnetic absorber is modeled, and the corresponding electromagnetic coupling coefficient is tested. A cantilever beam is employed to verify the broadband vibration absorption of the negative resistance (NR) shunted electromagnetic absorber (NR absorber) and the negative inductance NR shunted electromagnetic absorber (NINR absorber). The governing equations of the beam with two absorbers are derived, and the experiments are set up. The results point out that the NR and NINR absorbers can attenuate the broadband vibration. The proposed absorbers do not need the feedback system and the real-time controller compared to the active absorber; hence, they have great application potential in aerospace and in submarine applications, as well as in civil and mechanical engineering. (paper)

  5. Broadband Near-Infrared Quantum Cutting in Metal-Ion Codoped Y3Al5O12 Thin Films Grown by Pulsed-Laser Deposition for Solar Cell Application

    Directory of Open Access Journals (Sweden)

    Mei Kwan Lau

    2013-01-01

    Full Text Available We have deposited thin films of yttrium aluminum garnet (YAG doped with Ce3+ and Yb3+ on quartz and silicon substrates by pulsed laser deposition. Near-infrared (NIR quantum cutting which involves the emission of NIR photons through the downconversion from Ce3+ to Yb3+ is realized. Upon the broadband excitation of Ce3+ ions with a visible photon at the peak wavelength of 450 nm, NIR photons are generated by Yb3+ ions, with an emission wavelength centered at 1030 nm. The luminescent decay curves of Ce3+ were recorded as a supporting evidence corresponding to the energy transfer. This work offers a better and more convenient approach compatible with crystalline silicon solar cell compared to conventional bulk phosphors.

  6. 1984: On monitoring cell fate in three-dimensional polymeric scaffolds for tissue engineering applications

    OpenAIRE

    Leferink, Anne Marijke

    2014-01-01

    In cartilage and bone engineering there is a high need for methods to replace traditional tissue and organ transplantation approaches to overcome the currently faced problems of donor shortage and invasiveness of the transplantation procedure. Although many promising advances have been made in the past decades in in vitro tissue engineering, quality control remains a challenge. Most conventional methods to assess the quality of a tissue engineered construct, e.g. by studying cell fate and tis...

  7. Environmental parameters influence non-viral transfection of human mesenchymal stem cells for tissue engineering applications

    OpenAIRE

    King, William J.; Kouris, Nicholas A.; Choi, Siyoung; Ogle, Brenda M.; Murphy, William L.

    2012-01-01

    Non-viral transfection is a promising technique which could be used to increase the therapeutic potential of stem cells. The purpose of this study was to explore practical culture parameters of relevance in potential human mesenchymal stem cell (hMSC) clinical and tissue engineering applications, including type of polycationic transfection reagent, N/P ratio and dose of polycation/pDNA polyplexes, cell passage number, cell density, and cell proliferation. The non-viral transfection efficiency...

  8. Broadband Rotational Spectroscopy

    Science.gov (United States)

    Pate, Brooks

    2014-06-01

    The past decade has seen several major technology advances in electronics operating at microwave frequencies making it possible to develop a new generation of spectrometers for molecular rotational spectroscopy. High-speed digital electronics, both arbitrary waveform generators and digitizers, continue on a Moore's Law-like development cycle that started around 1993 with device bandwidth doubling about every 36 months. These enabling technologies were the key to designing chirped-pulse Fourier transform microwave (CP-FTMW) spectrometers which offer significant sensitivity enhancements for broadband spectrum acquisition in molecular rotational spectroscopy. A special feature of the chirped-pulse spectrometer design is that it is easily implemented at low frequency (below 8 GHz) where Balle-Flygare type spectrometers with Fabry-Perot cavity designs become technologically challenging due to the mirror size requirements. The capabilities of CP-FTMW spectrometers for studies of molecular structure will be illustrated by the collaborative research effort we have been a part of to determine the structures of water clusters - a project which has identified clusters up to the pentadecamer. A second technology trend that impacts molecular rotational spectroscopy is the development of high power, solid state sources in the mm-wave/THz regions. Results from the field of mm-wave chirped-pulse Fourier transform spectroscopy will be described with an emphasis on new problems in chemical dynamics and analytical chemistry that these methods can tackle. The third (and potentially most important) technological trend is the reduction of microwave components to chip level using monolithic microwave integrated circuits (MMIC) - a technology driven by an enormous mass market in communications. Some recent advances in rotational spectrometer designs that incorporate low-cost components will be highlighted. The challenge to the high-resolution spectroscopy community - as posed by Frank De

  9. Engineering PQS biosynthesis pathway for enhancement of bioelectricity production in Pseudomonas aeruginosa microbial fuel cells

    DEFF Research Database (Denmark)

    Wang, Victor Bochuan; Chua, Song-Lin; Cao, Bin;

    2013-01-01

    . aeruginosa strain that produces higher concentrations of phenazines under anaerobic conditions by over-expressing the PqsE effector in a PQS negative ΔpqsC mutant. The engineered strain exhibited an improved electrical performance in microbial fuel cells (MFCs) and potentiostat-controlled electrochemical...... genetic engineering is a suitable technique to improve power output of bioelectrochemical systems....

  10. Prospects of microbial cell factories developed through systems metabolic engineering.

    Science.gov (United States)

    Gustavsson, Martin; Lee, Sang Yup

    2016-09-01

    While academic-level studies on metabolic engineering of microorganisms for production of chemicals and fuels are ever growing, a significantly lower number of such production processes have reached commercial-scale. In this work, we review the challenges associated with moving from laboratory-scale demonstration of microbial chemical or fuel production to actual commercialization, focusing on key requirements on the production organism that need to be considered during the metabolic engineering process. Metabolic engineering strategies should take into account techno-economic factors such as the choice of feedstock, the product yield, productivity and titre, and the cost effectiveness of midstream and downstream processes. Also, it is important to develop an industrial strain through metabolic engineering for pathway construction and flux optimization together with increasing tolerance to products and inhibitors present in the feedstock, and ensuring genetic stability and strain robustness under actual fermentation conditions. PMID:27435545

  11. Driving demand for broadband networks and services

    CERN Document Server

    Katz, Raul L

    2014-01-01

    This book examines the reasons why various groups around the world choose not to adopt broadband services and evaluates strategies to stimulate the demand that will lead to increased broadband use. It introduces readers to the benefits of higher adoption rates while examining the progress that developed and emerging countries have made in stimulating broadband demand. By relying on concepts such as a supply and demand gap, broadband price elasticity, and demand promotion, this book explains differences between the fixed and mobile broadband demand gap, introducing the notions of substitution and complementarity between both platforms. Building on these concepts, ‘Driving Demand for Broadband Networks and Services’ offers a set of best practices and recommendations aimed at promoting broadband demand.  The broadband demand gap is defined as individuals and households that could buy a broadband subscription because they live in areas served by telecommunications carriers but do not do so because of either ...

  12. Development of Synthetic and Natural Materials for Tissue Engineering Applications Using Adipose Stem Cells

    Directory of Open Access Journals (Sweden)

    Yunfan He

    2016-01-01

    Full Text Available Adipose stem cells have prominent implications in tissue regeneration due to their abundance and relative ease of harvest from adipose tissue and their abilities to differentiate into mature cells of various tissue lineages and secrete various growth cytokines. Development of tissue engineering techniques in combination with various carrier scaffolds and adipose stem cells offers great potential in overcoming the existing limitations constraining classical approaches used in plastic and reconstructive surgery. However, as most tissue engineering techniques are new and highly experimental, there are still many practical challenges that must be overcome before laboratory research can lead to large-scale clinical applications. Tissue engineering is currently a growing field of medical research; in this review, we will discuss the progress in research on biomaterials and scaffolds for tissue engineering applications using adipose stem cells.

  13. Fetal and adult liver stem cells for liver regeneration and tissue engineering.

    Science.gov (United States)

    Fiegel, H C; Lange, Claudia; Kneser, U; Lambrecht, W; Zander, A R; Rogiers, X; Kluth, D

    2006-01-01

    For the development of innovative cell-based liver directed therapies, e.g. liver tissue engineering, the use of stem cells might be very attractive to overcome the limitation of donor liver tissue. Liver specific differentiation of embryonic, fetal or adult stem cells is currently under investigation. Different types of fetal liver (stem) cells during development were identified, and their advantageous growth potential and bipotential differentiation capacity were shown. However, ethical and legal issues have to be addressed before using fetal cells. Use of adult stem cells is clinically established, e.g. transplantation of hematopoietic stem cells. Other bone marrow derived liver stem cells might be mesenchymal stem cells (MSC). However, the transdifferentiation potential is still in question due to the observation of cellular fusion in several in vivo experiments. In vitro experiments revealed a crucial role of the environment (e.g. growth factors and extracellular matrix) for specific differentiation of stem cells. Co-cultured liver cells also seemed to be important for hepatic gene expression of MSC. For successful liver cell transplantation, a novel approach of tissue engineering by orthotopic transplantation of gel-immobilized cells could be promising, providing optimal environment for the injected cells. Moreover, an orthotopic tissue engineering approach using bipotential stem cells could lead to a repopulation of the recipients liver with healthy liver and biliary cells, thus providing both hepatic functions and biliary excretion. Future studies have to investigate, which stem cell and environmental conditions would be most suitable for the use of stem cells for liver regeneration or tissue engineering approaches. PMID:16989722

  14. Prospect of Stem Cells in Bone Tissue Engineering: A Review

    OpenAIRE

    Azizeh-Mitra Yousefi; James, Paul F.; Rosa Akbarzadeh; Aswati Subramanian; Conor Flavin; Hassane Oudadesse

    2016-01-01

    Mesenchymal stem cells (MSCs) have been the subject of many studies in recent years, ranging from basic science that looks into MSCs properties to studies that aim for developing bioengineered tissues and organs. Adult bone marrow-derived mesenchymal stem cells (BM-MSCs) have been the focus of most studies due to the inherent potential of these cells to differentiate into various cell types. Although, the discovery of induced pluripotent stem cells (iPSCs) represents a paradigm shift in our u...

  15. Genetic Engineering of Mesenchymal Stem Cells to Induce Their Migration and Survival

    Science.gov (United States)

    Nowakowski, Adam; Walczak, Piotr; Lukomska, Barbara; Janowski, Miroslaw

    2016-01-01

    Mesenchymal stem cells (MSCs) are very attractive for regenerative medicine due to their relatively easy derivation and broad range of differentiation capabilities, either naturally or induced through cell engineering. However, efficient methods of delivery to diseased tissues and the long-term survival of grafted cells still need improvement. Here, we review genetic engineering approaches designed to enhance the migratory capacities of MSCs, as well as extend their survival after transplantation by the modulation of prosurvival approaches, including prevention of senescence and apoptosis. We highlight some of the latest examples that explore these pivotal points, which have great relevance in cell-based therapies.

  16. Broadband Quantum Cryptography

    CERN Document Server

    Rogers, Daniel

    2010-01-01

    Quantum cryptography is a rapidly developing field that draws from a number of disciplines, from quantum optics to information theory to electrical engineering. By combining some fundamental quantum mechanical principles of single photons with various aspects of information theory, quantum cryptography represents a fundamental shift in the basis for security from numerical complexity to the fundamental physical nature of the communications channel. As such, it promises the holy grail of data security: theoretically unbreakable encryption. Of course, implementing quantum cryptography in real br

  17. Induction of insulin secretion in engineered liver cells by nitric oxide

    Directory of Open Access Journals (Sweden)

    Özcan Sabire

    2007-10-01

    Full Text Available Abstract Background Type 1 Diabetes Mellitus results from an autoimmune destruction of the pancreatic beta cells, which produce insulin. The lack of insulin leads to chronic hyperglycemia and secondary complications, such as cardiovascular disease. The currently approved clinical treatments for diabetes mellitus often fail to achieve sustained and optimal glycemic control. Therefore, there is a great interest in the development of surrogate beta cells as a treatment for type 1 diabetes. Normally, pancreatic beta cells produce and secrete insulin only in response to increased blood glucose levels. However in many cases, insulin secretion from non-beta cells engineered to produce insulin occurs in a glucose-independent manner. In the present study we engineered liver cells to produce and secrete insulin and insulin secretion can be stimulated via the nitric oxide pathway. Results Expression of either human insulin or the beta cell specific transcription factors PDX-1, NeuroD1 and MafA in the Hepa1-6 cell line or primary liver cells via adenoviral gene transfer, results in production and secretion of insulin. Although, the secretion of insulin is not significantly increased in response to high glucose, treatment of these engineered liver cells with L-arginine stimulates insulin secretion up to three-fold. This L-arginine-mediated insulin release is dependent on the production of nitric oxide. Conclusion Liver cells can be engineered to produce insulin and insulin secretion can be induced by treatment with L-arginine via the production of nitric oxide.

  18. The potential of nanofibers in tissue engineering and stem cell therapy.

    Science.gov (United States)

    Gholizadeh-Ghaleh Aziz, Shiva; Gholizadeh-Ghaleh Aziz, Sara; Akbarzadeh, Abolfazl

    2016-08-01

    Electrospinning is a technique in which materials in solution are shaped into continuous nano- and micro-sized fibers. Combining stem cells with biomaterial scaffolds and nanofibers affords a favorable approach for bone tissue engineering, stem cell growth and transfer, ocular surface reconstruction, and treatment of congenital corneal diseases. This review seeks to describe the current examples of the use of scaffolds in stem cell therapy. Stem cells are classified as adult or embryonic stem (ES) cells, and the advantages and drawbacks of each group are detailed. The nanofibers and scaffolds are further classified in Tables I and II , which describe specific examples from the literature. Finally, the current applications of biomaterial scaffolds containing stem cells for tissue engineering applications are presented. Overall, this review seeks to give an overview of the biomaterials available for use in combination with stem cells, and the application of nanofibers in stem cell therapy. PMID:26042482

  19. 350 nm Broadband Supercontinuum Generation Using Dispersion Engineered Near Zero Ultraflat Square-Lattice PCF around 1.55 μm and Fabrication Tolerance Analysis

    OpenAIRE

    Maji, Partha Sona; Roy Chaudhuri, Partha

    2014-01-01

    In this work, a new design of ultraflat dispersion PCF based on square-lattice geometry with all uniform air holes towards broadband smooth SCG around the C-band of wavelength has been presented. The air hole of the inner ring was infiltrated with liquid of certain refractive indices. Numerical investigations establish a near zero ultraflattened dispersion of 0 ± 0.78 ps/nm/km in a wavelength range of 1496 nm to 2174 nm (678 nm bandwidth) covering most of the communications bands with the fir...

  20. Engineering Escherichia coli Cell Factories for n-Butanol Production.

    Science.gov (United States)

    Dong, Hongjun; Zhao, Chunhua; Zhang, Tianrui; Lin, Zhao; Li, Yin; Zhang, Yanping

    2016-01-01

    The production of n-butanol, as a widely applied solvent and potential fuel, is attracting much attention. The fermentative production of butanol coupled with the production of acetone and ethanol by Clostridium (ABE fermentation) was once one of the oldest biotechnological processes, ranking second in scale behind ethanol fermentation. However, there remain problems with butanol production by Clostridium, especially the difficulty in genetically manipulating clostridial strains. In recent years, many efforts have been made to produce butanol using non-native strains. Until now, the most advanced effort was the engineering of the user-friendly and widely studied Escherichia coli for butanol production. This paper reviews the current progress and problems relating to butanol production by engineered E. coli in terms of prediction using mathematical models, pathway construction, novel enzyme replacement, butanol toxicity, and tolerance engineering strategies. PMID:25662903

  1. Optimal multisine excitation design for broadband electrical impedance spectroscopy

    International Nuclear Information System (INIS)

    Electrical impedance spectroscopy (EIS) can be used to characterize biological materials in applications ranging from cell culture to body composition, including tissue and organ state. The emergence of cell therapy and tissue engineering opens up a new and promising field of application. While in most cases classical measurement techniques based on a frequency sweep can be used, EIS based on broadband excitations enables dynamic biological systems to be characterized when the measuring time and injected energy are a constraint. Myocardial regeneration, cell characterization in micro-fluidic systems and dynamic electrical impedance tomography are all examples of such applications. The weakness of such types of fast EIS measuring techniques resides in their intrinsic loss of accuracy. However, since most of the practical applications have no restriction over the excitation used, the input power spectrum can be appropriately designed to maximize the accuracy obtained from the measurements. This paper deals with the problem of designing the optimal multisine excitation for electrical bioimpedance measurements. The optimal multisine is obtained by the minimization of the Cramer–Rao lower bound, or what is the same, by maximizing the accuracy obtained from the measurements. Furthermore, because no analytical solution exists for global optimization involving time and frequency domains jointly, this paper presents the multisine optimization approach partially in both domains and then combines the results. As regards the frequency domain approach, a novel contribution is made for the multisine amplitude power spectrum. In the time domain, multisine is optimized by reducing its crest factor. Moreover, the impact on the information and accuracy of the impedance spectrum obtained from using different multisine amplitude power spectra is discussed, as well as the number of frequencies and frequency distributions. The theory is supported by a set of validation measurements

  2. Optimal multisine excitation design for broadband electrical impedance spectroscopy

    Science.gov (United States)

    Sanchez, B.; Vandersteen, G.; Bragos, R.; Schoukens, J.

    2011-11-01

    Electrical impedance spectroscopy (EIS) can be used to characterize biological materials in applications ranging from cell culture to body composition, including tissue and organ state. The emergence of cell therapy and tissue engineering opens up a new and promising field of application. While in most cases classical measurement techniques based on a frequency sweep can be used, EIS based on broadband excitations enables dynamic biological systems to be characterized when the measuring time and injected energy are a constraint. Myocardial regeneration, cell characterization in micro-fluidic systems and dynamic electrical impedance tomography are all examples of such applications. The weakness of such types of fast EIS measuring techniques resides in their intrinsic loss of accuracy. However, since most of the practical applications have no restriction over the excitation used, the input power spectrum can be appropriately designed to maximize the accuracy obtained from the measurements. This paper deals with the problem of designing the optimal multisine excitation for electrical bioimpedance measurements. The optimal multisine is obtained by the minimization of the Cramer-Rao lower bound, or what is the same, by maximizing the accuracy obtained from the measurements. Furthermore, because no analytical solution exists for global optimization involving time and frequency domains jointly, this paper presents the multisine optimization approach partially in both domains and then combines the results. As regards the frequency domain approach, a novel contribution is made for the multisine amplitude power spectrum. In the time domain, multisine is optimized by reducing its crest factor. Moreover, the impact on the information and accuracy of the impedance spectrum obtained from using different multisine amplitude power spectra is discussed, as well as the number of frequencies and frequency distributions. The theory is supported by a set of validation measurements when

  3. Remote Control of Tissue Interactions via Engineered Photo-switchable Cell Surfaces

    OpenAIRE

    Wei Luo; Abigail Pulsipher; Debjit Dutta; Lamb, Brian M.; Yousaf, Muhammad N.

    2014-01-01

    We report a general cell surface molecular engineering strategy via liposome fusion delivery to create a dual photo-active and bio-orthogonal cell surface for remote controlled spatial and temporal manipulation of microtissue assembly and disassembly. Cell surface tailoring of chemoselective functional groups was achieved by a liposome fusion delivery method and quantified by flow cytometry and characterized by a new cell surface lipid pull down mass spectrometry strategy. Dynamic co-culture ...

  4. An Assessment of Cell Culture Plate Surface Chemistry for in Vitro Studies of Tissue Engineering Scaffolds

    OpenAIRE

    Alexander Röder; Elena García-Gareta; Christina Theodoropoulos; Nikola Ristovski; Keith A. Blackwood; Woodruff, Maria A.

    2015-01-01

    The use of biopolymers as a three dimensional (3D) support structure for cell growth is a leading tissue engineering approach in regenerative medicine. Achieving consistent cell seeding and uniform cell distribution throughout 3D scaffold culture in vitro is an ongoing challenge. Traditionally, 3D scaffolds are cultured within tissue culture plates to enable reproducible cell seeding and ease of culture media change. In this study, we compared two different well-plates with different surface ...

  5. Observations involving broadband impedance modelling

    Energy Technology Data Exchange (ETDEWEB)

    Berg, J.S. [Stanford Linear Accelerator Center, Menlo Park, CA (United States)

    1996-08-01

    Results for single- and multi-bunch instabilities can be significantly affected by the precise model that is used for the broadband impedance. This paper discusses three aspects of broadband impedance modelling. The first is an observation of the effect that a seemingly minor change in an impedance model has on the single-bunch mode coupling threshold. The second is a successful attempt to construct a model for the high-frequency tails of an r.f. cavity. The last is a discussion of requirements for the mathematical form of an impedance which follow from the general properties of impedances. (author)

  6. Broadband perfect polarization conversion metasurfaces

    International Nuclear Information System (INIS)

    We propose a broadband perfect polarization conversion metasurface composed of copper sheet-backed asymmetric double spilt ring resonator (DSRR). The broadband perfect polarization convertibility results from metallic ground and multiple plasmon resonances of the DSRR. Physics of plasmon resonances are governed by the electric and magnetic resonances. Both the simulation and measured results show that the polarization conversion ratio (PCR) is higher than 99% for both x- and y-polarized normally incident EM waves and the fractional bandwidth is about 34.5%. The metasurface possesses the merits of high PCR and broad bandwidth, and thus has great application values in novel polarization-control devices. (paper)

  7. Cancer cell-oriented migration of mesenchymal stem cells engineered with an anticancer gene (PTEN: an imaging demonstration

    Directory of Open Access Journals (Sweden)

    Yang ZS

    2014-03-01

    Full Text Available Zhuo-Shun Yang,1,* Xiang-Jun Tang,2,* Xing-Rong Guo,1 Dan-Dan Zou,1 Xu-Yong Sun,3 Jing-Bo Feng,1 Jie Luo,1 Long-Jun Dai,1,4 Garth L Warnock4 1Hubei Key Laboratory of Stem Cell Research, Taihe Hospital, Hubei University of Medicine, Shiyan, People’s Republic of China; 2Department of Neurosurgery, Taihe Hospital, Hubei University of Medicine, Shiyan, People’s Republic of China; 3Guangxi Key Laboratory for Transplant Medicine, 303 Hospital of PLA, Nanning, People’s Republic of China; 4Department of Surgery, University of British Columbia, Vancouver, BC, Canada *These authors contributed equally to this work Background: Mesenchymal stem cells (MSCs have been considered to hold great potential as ideal carriers for the delivery of anticancer agents since the discovery of their tumor tropism. This study was performed to demonstrate the effects of phosphatase and tensin homolog (PTEN engineering on MSCs’ capacity for cancer cell-oriented migration. Methods: MSCs were engineered with a PTEN-bearing plasmid and the expression was confirmed with Western blotting. A human glioma cell line (DBTRG was used as the target cell; DBTRG cell-oriented migration of MSCs was monitored with a micro speed photographic system. Results: The expression of transfected PTEN in MSCs was identified by immunoblotting analysis and confirmed with cell viability assessment of target cells. The DBTRG cell-oriented migration of PTEN-engineered MSCs was demonstrated by a real-time dynamic monitoring system, and a phagocytosis-like action of MSCs was also observed. Conclusion: MSCs maintained their capacity for cancer cell-directed migration after they were engineered with anticancer genes. This study provides the first direct evidence of MSCs’ tropism post-anticancer gene engineering. Keywords: gene therapy, mesenchymal stem cells, phosphatase and tensin homolog, cancer

  8. Engineering of the Embryonic and Adult Stem Cell Niches

    OpenAIRE

    Hosseinkhani, Mohsen; Shirazi, Reza; Rajaei, Farzad; Mahmoudi, Masoud; Mohammadi, Navid; Abbasi, Mahnaz

    2013-01-01

    Context Stem cells have the potential to generate a renewable source of cells for regenerative medicine due to their ability to self-renew and differentiate to various functional cell types of the adult organism. The extracellular microenvironment plays a pivotal role in controlling stem cell fate responses. Therefore, identification of appropriate environmental stimuli that supports cellular proliferation and lineage-specific differentiation is critical for the clinical application of the st...

  9. Characterisation of BHK-21 cells engineered to secrete human insulin

    OpenAIRE

    Gammell, Patrick; O'Driscoll, Lorraine; Clynes, Martin

    2003-01-01

    Autoimmune destruction of β cells in the pancreas leads to type I, or insulin dependent diabetes mellitus (IDDM), through the loss of endogenous insulin production capacity. This paper describes an attempt to generate ‘artificial’β cells using the fibroblast cell line BHK21. Stable transfectants expressing the human preproinsulin (PPI) gene were isolated and characterised. The resulting clone selected for further analysis (BHK-PPI-C16) was capable of secreting 0.12 pmol proinsulin/hr/105 cell...

  10. Control of stem cell fate by engineering their micro andnanoenvironment

    Institute of Scientific and Technical Information of China (English)

    Michelle F Griffin; Peter E Butler; Alexander M Seifalian; Deepak M Kalaskar

    2015-01-01

    Stem cells are capable of long-term self-renewal anddifferentiation into specialised cell types, making theman ideal candidate for a cell source for regenerativemedicine. The control of stem cell fate has become amajor area of interest in the field of regenerative medicineand therapeutic intervention. Conventional methodsof chemically inducing stem cells into specific lineagesis being challenged by the advances in biomaterialtechnology, with evidence highlighting that materialproperties are capable of driving stem cell fate. Materialsare being designed to mimic the clues stem cells receivein their in vivo stem cell niche including topographicaland chemical instructions. Nanotopographical clues thatmimic the extracellular matrix (ECM) in vivo have shownto regulate stem cell differentiation. The delivery of ECMcomponents on biomaterials in the form of short peptidessequences has also proved successful in directing stem celllineage. Growth factors responsible for controlling stemcell fate in vivo have also been delivered via biomaterialsto provide clues to determine stem cell differentiation. Analternative approach to guide stem cells fate is to providegenetic clues including delivering DNA plasmids andsmall interfering RNAs via scaffolds. This review, aims toprovide an overview of the topographical, chemical andmolecular clues that biomaterials can provide to guidestem cell fate. The promising features and challenges ofsuch approaches will be highlighted, to provide directionsfor future advancements in this exciting area of stem celltranslation for regenerative medicine.

  11. Engineered nanomaterial uptake and tissue distribution: from cell to organism

    Directory of Open Access Journals (Sweden)

    Kettiger H

    2013-08-01

    Full Text Available Helene Kettiger,1,* Angela Schipanski,2,* Peter Wick,2 Jörg Huwyler1 1Department of Pharmaceutical Sciences, Division of Pharmaceutical Technology, University of Basel, Basel, Switzerland; 2Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Materials-Biology Interactions, St Gallen, Switzerland *These authors contributed equally to this work Abstract: Improved understanding of interactions between nanoparticles and biological systems is needed to develop safety standards and to design new generations of nanomaterials. This article reviews the molecular mechanisms of cellular uptake of engineered nanoparticles, their intracellular fate, and their distribution within an organism. We have reviewed the available literature on the uptake and disposition of engineered nanoparticles. Special emphasis was placed on the analysis of experimental systems and their limitations with respect to their usefulness to predict the in vivo situation. The available literature confirms the need to study particle characteristics in an environment that simulates the situation encountered in biological systems. Phenomena such as protein binding and opsonization are of prime importance since they may have a strong impact on cellular internalization, biodistribution, and immunogenicity of nanoparticles in vitro and in vivo. Extrapolation from in vitro results to the in vivo situation in the whole organism remains a challenge. However, improved understanding of physicochemical properties of engineered nanoparticles and their influence on biological systems facilitates the design of nanomaterials that are safe, well tolerated, and suitable for diagnostic or therapeutic use in humans. Keywords: biodistribution, cellular transport, cellular uptake, endocytosis, engineered nanomaterials, nanosafety

  12. 350 nm Broadband Supercontinuum Generation Using Dispersion Engineered Near Zero Ultraflat Square-Lattice PCF around 1.55 μm and Fabrication Tolerance Analysis.

    Science.gov (United States)

    Maji, Partha Sona; Roy Chaudhuri, Partha

    2014-01-01

    In this work, a new design of ultraflat dispersion PCF based on square-lattice geometry with all uniform air holes towards broadband smooth SCG around the C-band of wavelength has been presented. The air hole of the inner ring was infiltrated with liquid of certain refractive indices. Numerical investigations establish a near zero ultraflattened dispersion of 0 ± 0.78 ps/nm/km in a wavelength range of 1496 nm to 2174 nm (678 nm bandwidth) covering most of the communications bands with the first zero dispersion wavelength around 1.54 μm. With the optimized ultraflattened fiber, we have achieved a broadband SC spectrum with FWHM of 350 nm with the central wavelength of 1550 nm with less than a meter long of the fiber by using a picosecond pulse laser. We have also analyzed the sensitivity of the optimized dispersion design by small variations from the optimum value of the geometrical structural parameters. Our investigations establish that for a negative change of PCF parameters, the profile retains the smooth and flat SCG spectra; however, for a positive change, the smooth and a flat spectrum is lost. The new design of the fiber will be capable of covering huge diverse field of DWDM sources, spectroscopy, meteorology, optical coherence tomography, and optical sensing. PMID:27355018

  13. Engineering cell-fluorescent ion track hybrid detectors

    International Nuclear Information System (INIS)

    The lack of sensitive biocompatible particle track detectors has so far limited parallel detection of physical energy deposition and biological response. Fluorescent nuclear track detectors (FNTDs) based on Al2O3:C,Mg single crystals combined with confocal laser scanning microscopy (CLSM) provide 3D information on ion tracks with a resolution limited by light diffraction. Here we report the development of next generation cell-fluorescent ion track hybrid detectors (Cell-Fit-HD). The biocompatibility of FNTDs was tested using six different cell lines, i.e. human non-small cell lung carcinoma (A549), glioblastoma (U87), androgen independent prostate cancer (PC3), epidermoid cancer (A431) and murine (VmDk) glioma SMA-560. To evaluate cell adherence, viability and conformal coverage of the crystals different seeding densities and alternative coating with extracellular matrix (fibronectin) was tested. Carbon irradiation was performed in Bragg peak (initial 270.55 MeV u−1). A series of cell compartment specific fluorescence stains including nuclear (HOECHST), membrane (Glut-1), cytoplasm (Calcein AM, CM-DiI) were tested on Cell-Fit-HDs and a single CLSM was employed to co-detect the physical (crystal) as well as the biological (cell layer) information. The FNTD provides a biocompatible surface. Among the cells tested, A549 cells formed the most uniform, viable, tightly packed epithelial like monolayer. The ion track information was not compromised in Cell-Fit-HD as compared to the FNTD alone. Neither cell coating and culturing, nor additional staining procedures affected the properties of the FNTD surface to detect ion tracks. Standard immunofluorescence and live staining procedures could be employed to co-register cell biology and ion track information. The Cell-Fit-Hybrid Detector system is a promising platform for a multitude of studies linking biological response to energy deposition at high level of optical microscopy resolution

  14. Development of yeast cell factories for consolidated bioprocessing of lignocellulose to bioethanol through cell surface engineering.

    Science.gov (United States)

    Hasunuma, Tomohisa; Kondo, Akihiko

    2012-01-01

    To build an energy and material secure future, a next generation of renewable fuels produced from lignocellulosic biomass is required. Although lignocellulosic biomass, which represents an abundant, inexpensive and renewable source for bioethanol production, is of great interest as a feedstock, the complicated ethanol production processes involved make the cost of producing bioethanol from it higher compared to corn starch and cane juice. Therefore, consolidated bioprocessing (CBP), which combines enzyme production, saccharification and fermentation in a single step, has gained increased recognition as a potential bioethanol production system. CBP requires a highly engineered microorganism developed for several different process-specific characteristics. The dominant strategy for engineering a CBP biocatalyst is to express multiple components of a cellulolytic system from either fungi or bacteria in the yeast Saccharomyces cerevisiae. The development of recombinant yeast strains displaying cellulases and hemicellulases on the cell surface represents significant progress toward realization of CBP. Regardless of the process used for biomass hydrolysis, CBP-enabling microorganisms encounter a variety of toxic compounds produced during biomass pretreatment that inhibit microbial growth and ethanol yield. Systems biology approaches including disruptome screening, transcriptomics, and metabolomics have been recently exploited to gain insight into the molecular and genetic traits involved in tolerance and adaptation to the fermentation inhibitors. In this review, we focus on recent advances in development of yeast strains with both the ability to directly convert lignocellulosic material to ethanol and tolerance in the harsh environments containing toxic compounds in the presence of ethanol. PMID:22085593

  15. Environmental cues to guide stem cell fate decision for tissue engineering applications.

    Science.gov (United States)

    Alsberg, Eben; von Recum, Horst A; Mahoney, Melissa J

    2006-09-01

    The human body contains a variety of stem cells capable of both repeated self-renewal and production of specialised, differentiated progeny. Critical to the implementation of these cells in tissue engineering strategies is a thorough understanding of which external signals in the stem cell microenvironment provide cues to control their fate decision in terms of proliferation or differentiation into a desired, specific phenotype. These signals must then be incorporated into tissue regeneration approaches for regulated exposure to stem cells. The precise spatial and temporal presentation of factors directing stem cell behaviour is extremely important during embryogenesis, development and natural healing events, and it is possible that this level of control will be vital to the success of many regenerative therapies. This review covers existing tissue engineering approaches to guide the differentiation of three disparate stem cell populations: mesenchymal, neural and endothelial. These progenitor cells will be of central importance in many future connective, neural and vascular tissue regeneration technologies. PMID:16918253

  16. The Skill Complementarity of Broadband Internet

    OpenAIRE

    Akerman, Anders; Gaarder, Ingvil; Mogstad, Magne

    2013-01-01

    Does adoption of broadband internet in firms enhance labor productivity and increase wages? And is this technological change skill biased or factor neutral? We exploit rich Norwegian data with firm-level information on value added, factor inputs and broadband adoption to answer these questions. We estimate production functions where firms can change their technology by adopting broadband internet. A public program with limited funding rolled out broadband access points, and provides plausibly...

  17. Broadband Internet's Value for Rural America

    OpenAIRE

    Stenberg, Peter L.; Morehart, Mitchell J.; Vogel, Stephen J.; Cromartie, John; Breneman, Vincent E.; Brown, Dennis M.

    2009-01-01

    As broadband—or high-speed—Internet use has spread, Internet applications requiring high transmission speeds have become an integral part of the “Information Economy,” raising concerns about those who lack broadband access. This report analyzes (1) rural broadband use by consumers, the community-at-large, and businesses; (2) rural broadband availability; and (3) broadband’s social and economic effects on rural areas. It also summarizes results from an ERS-sponsored workshop on rural broadband...

  18. Broadband opportunity in Europe’s new member states

    Czech Academy of Sciences Publication Activity Database

    Hill, G.; Kuchar, Anton; Blazic, B.; Granat, J.; Kolias, C.

    [Bordeaux]: BREAD , 2005, W01B.01--. [Broadband Europe 2005. Bordeaux (FR), 12.12.2005-14.12.2005] Grant ostatní: BReATH Consortium EU(XE) EC FP6 1ST Programme Institutional research plan: CEZ:AV0Z20670512 Keywords : Internet * telecommunication networks * cable television Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering http://www.bbeurope.org Parallel Sesion WO0B - Regional Projects I

  19. Cell-Derived Extracellular Matrix: Basic Characteristics and Current Applications in Orthopedic Tissue Engineering.

    Science.gov (United States)

    Zhang, Weixiang; Zhu, Yun; Li, Jia; Guo, Quanyi; Peng, Jiang; Liu, Shichen; Yang, Jianhua; Wang, Yu

    2016-06-01

    The extracellular matrix (ECM) is a dynamic and intricate microenvironment with excellent biophysical, biomechanical, and biochemical properties, which can directly or indirectly regulate cell proliferation, adhesion, migration, and differentiation, as well as plays key roles in homeostasis and regeneration of tissues and organs. The ECM has attracted a great deal of attention with the rapid development of tissue engineering in the field of regenerative medicine. Tissue-derived ECM scaffolds (also referred to as decellularized tissues and whole organs) are considered a promising therapy for the repair of musculoskeletal defects, including those that are widely used in orthopedics, although there are a few shortcomings. Similar to tissue-derived ECM scaffolds, cell-derived ECM scaffolds also have highly advantageous biophysical and biochemical properties, in particular their ability to be produced in vitro from a number of different cell types. Furthermore, cell-derived ECM scaffolds more closely resemble native ECM microenvironments. The products of cell-derived ECM have a wide range of biomedical applications; these include reagents for cell culture substrates and biomaterials for scaffolds, hybrid scaffolds, and living cell sheet coculture systems. Although cell-derived ECM has only just begun to be investigated, it has great potential as a novel approach for cell-based tissue repair in orthopedic tissue engineering. This review summarizes and analyzes the various types of cell-derived ECM products applied in cartilage, bone, and nerve tissue engineering in vitro or in vivo and discusses future directions for investigation of cell-derived ECM. PMID:26671674

  20. Characterization of human skin cells for tissue engineering applications by Raman spectroscopy

    Science.gov (United States)

    Pudlas, Marieke; Koch, Steffen; Bolwien, Carsten; Walles, Heike

    2010-02-01

    In the field of cell culture and tissue engineering is an increasing need for non-invasive methods to analyze living cells in vitro. One important application is the cell characterization in tissue engineering products. Raman spectroscopy is a method which analyzes cells without lysis, fixation or the use of any chemicals and do not affect cell vitality adversely if suitable laser powers and wavelength are used. This purely optical technique is based on inelastic scattering of laser photons by molecular vibrations of biopolymers. Basically Raman spectra of cells contain typical fingerprint regions and information about cellular properties. Characteristic peaks in Raman spectra could be assigned to biochemical molecules like proteins, nucleic acid or lipids. The distinction of cell types by a multivariate analysis of Raman spectra is possible due to their biochemical differences. As this method allows a characterization of cells without any cell damage it is a promising technology for the quality control of cells in tissue engineering or cell culture applications.

  1. Status of Broadband development in the Czech Republic and open issues

    Czech Academy of Sciences Publication Activity Database

    Kuchar, Anton

    Athens: BReATH Consortium, 2006, -. [Workshop Promoting Broadband Across Europe. Athens (GR), 04.09.2006] Grant ostatní: BReATH Consortium EU(XE) EC FP6 1ST Programme Institutional research plan: CEZ:AV0Z20670512 Keywords : telecommunication networks * broadband networks * Internet Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering http://www.ist-breath.net/events/eventE5.html

  2. What drives and what hinders development of broadband in the Czech republic

    Czech Academy of Sciences Publication Activity Database

    Kuchar, Anton

    Geneve: BREAD , 2006, ---. [BroadBand Europe 2006. Geneve (CH), 11.12.2006-14.12.2006] Grant ostatní: BReATH Consortium EU(XE) EC FP6 1ST Programme Institutional research plan: CEZ:AV0Z20670512 Keywords : Internet * telecommunication networks * broadband networks Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering http://www.bbeurope.org, papers BB W1B-4

  3. Broadband Acoustic Liner Optimization Study Using Novel Poro-elastic Materials

    OpenAIRE

    Mitchell, Kelsey Ryan

    2015-01-01

    With the continual challenges associated with reducing aircraft engine noise, there is need for acoustic liner configurations that target broadband performance. This thesis experimentally and analytically investigates passive noise control methods to improve broadband frequency attenuation through various acoustic liner designs. The inclusion of acoustic metamaterials within these liners is examined and optimized. The metamaterials studied consist of resonant and non-resonant materials which ...

  4. Engineering complex tissue-like microgel arrays for evaluating stem cell differentiation

    Science.gov (United States)

    Guermani, Enrico; Shaki, Hossein; Mohanty, Soumyaranjan; Mehrali, Mehdi; Arpanaei, Ayyoob; Gaharwar, Akhilesh K.; Dolatshahi-Pirouz, Alireza

    2016-01-01

    Development of tissue engineering scaffolds with native-like biology and microarchitectures is a prerequisite for stem cell mediated generation of off-the-shelf-tissues. So far, the field of tissue engineering has not full-filled its grand potential of engineering such combinatorial scaffolds for engineering functional tissues. This is primarily due to the many challenges associated with finding the right microarchitectures and ECM compositions for optimal tissue regeneration. Here, we have developed a new microgel array to address this grand challenge through robotic printing of complex stem cell-laden microgel arrays. The developed microgel array platform consisted of various microgel environments that where composed of native-like cellular microarchitectures resembling vascularized and bone marrow tissue architectures. The feasibility of our array system was demonstrated through localized cell spreading and osteogenic differentiation of human mesenchymal stem cells (hMSCs) into complex tissue-like structures. In summary, we have developed a tissue-like microgel array for evaluating stem cell differentiation within complex and heterogeneous cell microenvironments. We anticipate that the developed platform will be used for high-throughput identification of combinatorial and native-like scaffolds for tissue engineering of functional organs. PMID:27465860

  5. High-sensitivity broadband microwave spectroscopy with small nonresonant coils

    Science.gov (United States)

    Mahdjour, H.; Clark, W. G.; Baberschke, K.

    1986-06-01

    The use of a small, nonresonant, coil of micron dimensions as the microwave magnetic field structure of a broadband electron-spin-resonance (ESR) spectrometer is described. The coil is driven by a broadband microwave generator which operates between 0.1 and 8.5 GHz. The samples may fill the coil to approximately 100 percent. It is shown that for small size samples this system offers higher sensitivity than a conventional cavity spectrometer. Because the system is broadband, either frequency scans or the conventional magnetic field scans can be used to traverse the resonance. Examples for DPPH and for the spin glass AgMn using this method are reported. Since the sample coil is small, it has many potential applications, such as insertion into the mixing chamber of dilution refrigerator or high-pressure cell, efficient use of power in ENDOR and other double resonance experiments, and rapid recovery from transients in pulsed ESR experiments.

  6. Software Engineering Tools for Scientific Models

    Science.gov (United States)

    Abrams, Marc; Saboo, Pallabi; Sonsini, Mike

    2013-01-01

    Software tools were constructed to address issues the NASA Fortran development community faces, and they were tested on real models currently in use at NASA. These proof-of-concept tools address the High-End Computing Program and the Modeling, Analysis, and Prediction Program. Two examples are the NASA Goddard Earth Observing System Model, Version 5 (GEOS-5) atmospheric model in Cell Fortran on the Cell Broadband Engine, and the Goddard Institute for Space Studies (GISS) coupled atmosphere- ocean model called ModelE, written in fixed format Fortran.

  7. Plasticity of Ectomesenchymal Stem Cells and its Ability of Producing Tissue Engineering Tooth by Recombining with Dental Epithelial Cells

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    1 IntroductionRecently, it has been found that human dental pulp stem cells could generate dentin-pulp complex-like structures in nude mice, but studies on tissue engineering tooth-like structures by cultured human dental epithelial and mesenchymal stem cells are still reported rarely. Ectomesenchyme is an unique structure of vertebrates embryo compose of postmigratory cephalic neural crest cells (NCC) and its derivatives. The aim of the present study was to identify and isolate the ectomesenchymal stem cel...

  8. Challenges in tissue engineering - towards cell control inside artificial scaffolds.

    Science.gov (United States)

    Emmert, M; Witzel, P; Heinrich, D

    2016-05-11

    Control of living cells is vital for the survival of organisms. Each cell inside an organism is exposed to diverse external mechano-chemical cues, all coordinated in a spatio-temporal pattern triggering individual cell functions. This complex interplay between external chemical cues and mechanical 3D environments is translated into intracellular signaling loops. Here, we describe how external mechano-chemical cues control cell functions, especially cell migration, and influence intracellular information transport. In particular, this work focuses on the quantitative analysis of (1) intracellular vesicle transport to understand intracellular state changes in response to external cues, (2) cellular sensing of external chemotactic cues, and (3) the cells' ability to migrate in 3D structured environments, artificially fabricated to mimic the 3D environment of tissue in the human body. PMID:27139622

  9. Human Cardiac Tissue Engineering: From Pluripotent Stem Cells to Heart Repair

    Science.gov (United States)

    Jackman, Christopher P.; Shadrin, Ilya Y.; Carlson, Aaron L.; Bursac, Nenad

    2014-01-01

    Engineered cardiac tissues hold great promise for use in drug and toxicology screening, in vitro studies of human physiology and disease, and as transplantable tissue grafts for myocardial repair. In this review, we discuss recent progress in cell-based therapy and functional tissue engineering using pluripotent stem cell-derived cardiomyocytes and we describe methods for delivery of cells into the injured heart. While significant hurdles remain, notable advances have been made in the methods to derive large numbers of pure human cardiomyocytes, mature their phenotype, and produce and implant functional cardiac tissues, bringing the field a step closer to widespread in vitro and in vivo applications. PMID:25599018

  10. Achieving universal access to broadband

    DEFF Research Database (Denmark)

    Falch, Morten; Henten, Anders

    2009-01-01

    The paper discusses appropriate policy measures for achieving universal access to broadband services in Europe. Access can be delivered by means of many different technology solutions described in the paper. This means a greater degree of competition and affects the kind of policy measures to be...

  11. Metabolically engineered cells for the production of polyunsaturated fatty acids

    DEFF Research Database (Denmark)

    2005-01-01

    improvement of the PUFA content in the host organism through fermentation optimization, e.g. decreasing the temperature and/or designing an optimal medium, or through improving the flux towards fatty acids by metabolic engineering, e.g. through over-expression of fatty acid synthases, over-expression of other...... enzymes involved in biosynthesis of the precursor for PUFAs, or codon optimization of the heterologous genes, or expression of heterologous enzymes involved in the biosynthesis of the precursor for PUFAs....

  12. Macromolecular cell surface engineering for accelerated and reversible cellular aggregation.

    Science.gov (United States)

    Amaral, Adérito J R; Pasparakis, George

    2015-12-25

    We report the synthesis of two simple copolymers that induce rapid cell aggregation within minutes in a fully reversible manner. The polymers can act as self-supporting "cellular glues" or as "drivers" of 3D cell spheroids/aggregates formation at minute concentrations. PMID:26478926

  13. Broadband perfect light trapping in the thinnest monolayer graphene-MoS2 photovoltaic cell: the new application of spectrum-splitting structure

    Science.gov (United States)

    Wu, Yun-Ben; Yang, Wen; Wang, Tong-Biao; Deng, Xin-Hua; Liu, Jiang-Tao

    2016-02-01

    The light absorption of a monolayer graphene-molybdenum disulfide photovoltaic (GM-PV) cell in a wedge-shaped microcavity with a spectrum-splitting structure is investigated theoretically. The GM-PV cell, which is three times thinner than the traditional photovoltaic cell, exhibits up to 98% light absorptance in a wide wavelength range. This rate exceeds the fundamental limit of nanophotonic light trapping in solar cells. The effects of defect layer thickness, GM-PV cell position in the microcavity, incident angle, and lens aberration on the light absorptance of the GM-PV cell are explored. Despite these effects, the GM-PV cell can still achieve at least 90% light absorptance with the current technology. Our proposal provides different methods to design light-trapping structures and apply spectrum-splitting systems.

  14. Ultra-broadband light trapping using nanotextured decoupled graphene multilayers

    Science.gov (United States)

    Anguita, José V.; Ahmad, Muhammad; Haq, Sajad; Allam, Jeremy; Silva, S. Ravi P.

    2016-01-01

    The ability to engineer a thin two-dimensional surface for light trapping across an ultra-broad spectral range is central for an increasing number of applications including energy, optoelectronics, and spectroscopy. Although broadband light trapping has been obtained in tall structures of carbon nanotubes with millimeter-tall dimensions, obtaining such broadband light–trapping behavior from nanometer-scale absorbers remains elusive. We report a method for trapping the optical field coincident with few-layer decoupled graphene using field localization within a disordered distribution of subwavelength-sized nanotexturing metal particles. We show that the combination of the broadband light–coupling effect from the disordered nanotexture combined with the natural thinness and remarkably high and wavelength-independent absorption of graphene results in an ultrathin (15 nm thin) yet ultra-broadband blackbody absorber, featuring 99% absorption spanning from the mid-infrared to the ultraviolet. We demonstrate the utility of our approach to produce the blackbody absorber on delicate opto-microelectromechanical infrared emitters, using a low-temperature, noncontact fabrication method, which is also large-area compatible. This development may pave a way to new fabrication methodologies for optical devices requiring light management at the nanoscale. PMID:26933686

  15. Biomass gasification integrated with a solid oxide fuel cell and Stirling engine

    DEFF Research Database (Denmark)

    Rokni, Masoud

    2014-01-01

    An integrated gasification solid oxide fuel cell (SOFC) and Stirling engine for combined heat and power application is analyzed. The target for electricity production is 120 kW. Woodchips are used as gasification feedstock to produce syngas, which is then used to feed the SOFC stacks for electric......An integrated gasification solid oxide fuel cell (SOFC) and Stirling engine for combined heat and power application is analyzed. The target for electricity production is 120 kW. Woodchips are used as gasification feedstock to produce syngas, which is then used to feed the SOFC stacks...... for electricity production. Unreacted hydrocarbons remaining after the SOFC are burned in a catalytic burner, and the hot off-gases from the burner are recovered in a Stirling engine for electricity and heat production. Domestic hot water is used as a heat sink for the Stirling engine. A complete balance...

  16. In vitro evaluation of cell-seeded chitosan films for peripheral nerve tissue engineering

    OpenAIRE

    Wrobel, Sandra; Serra, Sofia Cristina; Samy, S. M.; Sousa, Nuno; Heimann, Claudia; Barwig, Christina; Grothe, Claudia; Salgado, A. J.; Talini, Kirsten Haastert

    2014-01-01

    Natural biomaterials have attracted an increasing interest in the field of tissue-engineered nerve grafts, representing a possible alternative to autologous nerve transplantation. With the prospect of developing a novel entubulation strategy for transected nerves with cell-seeded chitosan films, we examined the biocompatibility of such films in vitro. Different types of rat Schwann cells (SCs)—immortalized, neonatal, and adult—as well as rat bone-marrow-derived mesenchymal stromal cells (BMSC...

  17. Engineering Adolescence: Maturation of Human Pluripotent Stem Cell-derived Cardiomyocytes

    OpenAIRE

    Yang, Xiulan; Pabon, Lil; Murry, Charles E.

    2014-01-01

    The discovery of human pluripotent stem cells (hPSCs), including both human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs), has opened up novel paths for a wide range of scientific studies. The capability to direct the differentiation of hPSCs into functional cardiomyocytes has provided a platform for regenerative medicine, development, tissue engineering, disease modeling, and drug toxicity testing. Despite exciting progress, achieving the optimal benefits has...

  18. Molecular and Nanoscale Engineering of High Efficiency Excitonic Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Jenekhe, Samson A. [Univ. of Washington, Seattle, WA (United States); Ginger, David S. [Univ. of Washington, Seattle, WA (United States); Cao, Guozhong [Univ. of Washington, Seattle, WA (United States)

    2016-01-15

    We combined the synthesis of new polymers and organic-inorganic hybrid materials with new experimental characterization tools to investigate bulk heterojunction (BHJ) polymer solar cells and hybrid organic-inorganic solar cells during the 2007-2010 period (phase I) of this project. We showed that the bulk morphology of polymer/fullerene blend solar cells could be controlled by using either self-assembled polymer semiconductor nanowires or diblock poly(3-alkylthiophenes) as the light-absorbing and hole transport component. We developed new characterization tools in-house, including photoinduced absorption (PIA) spectroscopy, time-resolved electrostatic force microscopy (TR-EFM) and conductive and photoconductive atomic force microscopy (c-AFM and pc-AFM), and used them to investigate charge transfer and recombination dynamics in polymer/fullerene BHJ solar cells, hybrid polymer-nanocrystal (PbSe) devices, and dye-sensitized solar cells (DSSCs); we thus showed in detail how the bulk photovoltaic properties are connected to the nanoscale structure of the BHJ polymer solar cells. We created various oxide semiconductor (ZnO, TiO2) nanostructures by solution processing routes, including hierarchical aggregates and nanorods/nanotubes, and showed that the nanostructured photoanodes resulted in substantially enhanced light-harvesting and charge transport, leading to enhanced power conversion efficiency of dye-sensitized solar cells.

  19. Engineering controlled mammalian type O-Glycosylation in plant cells

    DEFF Research Database (Denmark)

    Yang, Zhang; Drew, Damian Paul; Jørgensen, Bodil;

    2011-01-01

    Human mucins are large heavily O-glycosylated glycoproteins (>200 kDa), which account for the majority of proteins in mucus layers that e.g. hydrate, lubricate and protect cells from proteases as well as from pathogens. O-linked mucin glycans are truncated in many cancers, yielding truncated cancer...... specific glyco-peptide epitopes, such as the Tn epitope (GalNAc sugar attached to either Serine or Threonine), which are antigenic to the immune system. In the present study, we have identified plant cells as the only eukaryotic cells without mammalian type O-glycosylation or competing (for sites) O...

  20. Scaffoldless Tissue-engineered Dental Pulp Cell Constructs for Endodontic Therapy

    OpenAIRE

    Syed-Picard, F.N.; Ray, H.L.; Kumta, P.N.; Sfeir, C.

    2014-01-01

    A major cause of apical periodontitis after endodontic treatment is the bacterial infiltration which could have been challenged by the presence of a vital pulp. In this study, self-assembled, scaffoldless, three-dimensional (3D) tissues were engineered from dental pulp cells (DPCs) and assessed as a device for pulp regeneration. These engineered tissues were placed into the canal space of human tooth root segments that were capped on one end with calcium phosphate cement, and the entire syste...

  1. Metabolically engineered cells for the production of pinosylvin

    DEFF Research Database (Denmark)

    2008-01-01

    A genetically engineered micro-organism having an operative metabolic pathway producing cinnamoyl-CoA and producing pinosylvin therefrom by the action of a stilbene synthase is used for pinosylvin production. Said cinnamic acid may be formed from L-phenylalanine by a L-phenylalanine ammonia lyase...... (PAL) which is one accepting phenylalanine as a substrate and producing cinammic acid therefrom, preferably such that if the PAL also accepts tyrosine as a substrate and forms coumaric acid therefrom, the ratio Km(phenylalanine)/Km(tyrosine) for said PAL is less than 1:1 and if said micro-organism...

  2. Human umbilical cord stem cell encapsulation in novel macroporous and injectable fibrin for muscle tissue engineering.

    Science.gov (United States)

    Liu, Jun; Xu, Hockin H K; Zhou, Hongzhi; Weir, Michael D; Chen, Qianming; Trotman, Carroll Ann

    2013-01-01

    There has been little research on the seeding of human umbilical cord mesenchymal stem cells (hUCMSCs) in three-dimensional scaffolds for muscle tissue engineering. The objectives of this study were: (i) to seed hUCMSCs in a fibrin hydrogel containing fast-degradable microbeads (dMBs) to create macropores to enhance cell viability; and (ii) to investigate the encapsulated cell proliferation and myogenic differentiation for muscle tissue engineering. Mass fractions of 0-80% of dMBs were tested, and 35% of dMBs in fibrin was shown to avoid fibrin shrinkage while creating macropores and promoting cell viability. This construct was referred to as "dMB35". Fibrin without dMBs was termed "dMB0". Microbead degradation created macropores in fibrin and improved cell viability. The percentage of live cells in dMB35 reached 91% at 16 days, higher than the 81% in dMB0 (pACTN3). Elongated, multinucleated cells were formed with positive staining of myogenic specific proteins including myogenin, MYH, ACTN and actin alpha 1. Moreover, a significant increase in cell fusion was detected with myogenic induction. In conclusion, hUCMSCs were encapsulated in fibrin with degradable microbeads for the first time, achieving greatly enhanced cell viability and successful myogenic differentiation with formation of multinucleated myotubes. The injectable and macroporous fibrin-dMB-hUCMSC construct may be promising for muscle tissue engineering applications. PMID:22902812

  3. Remote Control of Tissue Interactions via Engineered Photo-switchable Cell Surfaces

    Science.gov (United States)

    Luo, Wei; Pulsipher, Abigail; Dutta, Debjit; Lamb, Brian M.; Yousaf, Muhammad N.

    2014-09-01

    We report a general cell surface molecular engineering strategy via liposome fusion delivery to create a dual photo-active and bio-orthogonal cell surface for remote controlled spatial and temporal manipulation of microtissue assembly and disassembly. Cell surface tailoring of chemoselective functional groups was achieved by a liposome fusion delivery method and quantified by flow cytometry and characterized by a new cell surface lipid pull down mass spectrometry strategy. Dynamic co-culture spheroid tissue assembly in solution and co-culture tissue multilayer assembly on materials was demonstrated by an intercellular photo-oxime ligation that could be remotely cleaved and disassembled on demand. Spatial and temporal control of microtissue structures containing multiple cell types was demonstrated by the generation of patterned multilayers for controlling stem cell differentiation. Remote control of cell interactions via cell surface engineering that allows for real-time manipulation of tissue dynamics may provide tools with the scope to answer fundamental questions of cell communication and initiate new biotechnologies ranging from imaging probes to drug delivery vehicles to regenerative medicine, inexpensive bioreactor technology and tissue engineering therapies.

  4. Engineering hot-cell windows for radiation protection

    International Nuclear Information System (INIS)

    Radiation protection considerations in the design and construction of hot-cell windows are discussed. The importance of evaluating the potential gamma spectra and neutron source terms is stressed. 11 references

  5. Stem Cells & Regenerative Medicine - From molecular embryology to tissue engineering

    Directory of Open Access Journals (Sweden)

    Carlo Alberto Redi

    2011-09-01

    Full Text Available Maria J. Barrero and Juan Carlos Izpisua Belmonte sign a very interesting paper on EMBO reports (Regenerating the epigenome, EMBO reports 12:208-215, 2011 where they point out that Organisms have evolved two strategies by which to achieve this: the maintenance of adult stem cells and the induction of stemcell properties in differentiated cells. In both cases, cells must undergo extensive epigenetic reprogramming to attain the specialized functions of the new tissue. Ultimately, the regenerative capacity of a tissue might depend on the plasticity of the cellular epigenome, which determines the ability of the cell to respond to injuryrelated signals. Understanding this epigenetic plasticity will allow the development of strategies to stimulate the regeneration of damaged tissues and organs in humans...

  6. Engineered nanoparticles mimicking cell membranes for toxin neutralization.

    Science.gov (United States)

    Fang, Ronnie H; Luk, Brian T; Hu, Che-Ming J; Zhang, Liangfang

    2015-08-01

    Protein toxins secreted from pathogenic bacteria and venomous animals rely on multiple mechanisms to overcome the cell membrane barrier to inflict their virulence effect. A promising therapeutic concept toward developing a broadly applicable anti-toxin platform is to administer cell membrane mimics as decoys to sequester these virulence factors. As such, lipid membrane-based nanoparticulates are an ideal candidate given their structural similarity to cellular membranes. This article reviews the virulence mechanisms employed by toxins at the cell membrane interface and highlights the application of cell-membrane mimicking nanoparticles as toxin decoys for systemic detoxification. In addition, the implication of particle/toxin nanocomplexes in the development of toxoid vaccines is discussed. PMID:25868452

  7. Design of high temperature irradiation materials inspection cells. (Spent fuel inspection cells) in the High Temperature Engineering Test Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Ino, Hiroichi; Ueta, Shouhei; Suzuki, Hiroshi; Sawa, Kazuhiro [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment; Tobita, Tsutomu [Nuclear Engineering Company, Ltd., Tokai, Ibaraki (Japan)

    2002-01-01

    This report summarizes design requirements and design results for shields, ventilation system and fuel handling devices for the high temperature irradiation materials inspection cells (spent fuel inspection cells). These cells are small cells to carry out few post-irradiation examinations of spent fuels, specimen, etc., which are irradiated in the High Temperature Engineering Test Reactor, since the cells should be built in limited space in the HTTR reactor building, the cells are designed considering relationship between the cells and the reactor building to utilize the limited space effectively. The cells consist of three partitioned hot cells with wall for neutron and gamma-ray shields, ventilation system including filtering units and fuel handling devices. The post-irradiation examinations of the fuels and materials are planed by using the cells and the Hot Laboratory of the Japan Materials Testing Reactor to establish the technology basis on high temperature gas-cooled reactors (HTGRs). In future, irradiation tests and post-irradiation examinations will be carried out with the cells to upgrade present HTGR technologies and to make the innovative basic research on high-temperature engineering. (author)

  8. Design of high temperature irradiation materials inspection cells. (Spent fuel inspection cells) in the High Temperature Engineering Test Reactor

    International Nuclear Information System (INIS)

    This report summarizes design requirements and design results for shields, ventilation system and fuel handling devices for the high temperature irradiation materials inspection cells (spent fuel inspection cells). These cells are small cells to carry out few post-irradiation examinations of spent fuels, specimen, etc., which are irradiated in the High Temperature Engineering Test Reactor, since the cells should be built in limited space in the HTTR reactor building, the cells are designed considering relationship between the cells and the reactor building to utilize the limited space effectively. The cells consist of three partitioned hot cells with wall for neutron and gamma-ray shields, ventilation system including filtering units and fuel handling devices. The post-irradiation examinations of the fuels and materials are planed by using the cells and the Hot Laboratory of the Japan Materials Testing Reactor to establish the technology basis on high temperature gas-cooled reactors (HTGRs). In future, irradiation tests and post-irradiation examinations will be carried out with the cells to upgrade present HTGR technologies and to make the innovative basic research on high-temperature engineering. (author)

  9. Hematopoietic Stem Cell Targeting with Surface-Engineered Lentiviral Vectors

    OpenAIRE

    sprotocols

    2014-01-01

    Authors: Els Verhoeyen and Francois-Loic Cosset Adapted from [*Gene Transfer: Delivery and Expression of DNA and RNA*](http://www.cshlpress.com/link/genetrnp.htm) (eds. Friedmann and Rossi). CSHL Press, Cold Spring Harbor, NY, USA, 2007. ### INTRODUCTION In the protocol presented here, hematopoietic stem cells (HSCs) are specifically transduced with a vector displaying the HSC-activating polypeptides, stem cell factor (SCF) and thrombopoietin (TPO). Targeted HSC transduction is e...

  10. Process Engineering of Stem Cells for Clinical Application

    OpenAIRE

    Serra, Maria Margarida de Carvalho Negrão

    2011-01-01

    Over the last decade, human embryonic stem cells (hESCs) have garnered a lot of attention owing to their inherent self-renewal ability and pluripotency. These characteristics have opened opportunities for potential stem cell-based regenerative medicines, for development of drug discovery platforms and as unique in vitro models for the study of early human development.(...) Fundação para a Ciência e a Tecnologia

  11. Systems biology and metabolic engineering of Arthrospira cell factories

    OpenAIRE

    Amornpan Klanchui; Tayvich Vorapreeda; Wanwipa Vongsangnak; Chiraphan Kannapho; Supapon Cheevadhanarak; Asawin Meechai

    2012-01-01

    Arthrospira are attractive candidates to serve as cell factories for production of many valuable compounds useful for food, feed, fuel and pharmaceutical industries. In connection with the development of sustainable bioprocessing, it is a challenge to design and develop efficient Arthrospira cell factories which can certify effective conversion from the raw materials (i.e. CO2 and sun light) into desired products. With the current availability of the genome sequences and metabolic models of A...

  12. Electron Acceptor Materials Engineering in Colloidal Quantum Dot Solar Cells

    KAUST Repository

    Liu, Huan

    2011-07-15

    Lead sulfide colloidal quantum dot (CQD) solar cells with a solar power conversion efficiency of 5.6% are reported. The result is achieved through careful optimization of the titanium dioxide electrode that serves as the electron acceptor. Metal-ion-doped sol-gel-derived titanium dioxide electrodes produce a tunable-bandedge, well-passivated materials platform for CQD solar cell optimization. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Thermodynamic Analysis of a Woodchips Gasification Integrated with Solid Oxide Fuel Cell and Stirling Engine

    DEFF Research Database (Denmark)

    Rokni, Masoud

    2013-01-01

    Integrated gasification Solid Oxide Fuel Cell (SOFC) and Stirling engine for combined heat and power application is analysed. The target for electricity production is 120 kW. Woodchips are used as gasification feedstock to produce syngas which is utilized for feeding the SOFC stacks for electricity...... production. Unreacted hydrocarbons after SOFC are burned in a catalytic burner and the hot off-gases from the burner are recovered in a Stirling engine for electricity and heat production. The domestic hot water is used as heat sink for the Stirling engine. A complete balance of plant is designed...

  14. On the road to synthetic life: the minimal cell and genome-scale engineering.

    Science.gov (United States)

    Juhas, Mario

    2016-06-01

    Synthetic biology employs rational engineering principles to build biological systems from the libraries of standard, well characterized biological parts. Biological systems designed and built by synthetic biologists fulfill a plethora of useful purposes, ranging from better healthcare and energy production to biomanufacturing. Recent advancements in the synthesis, assembly and "booting-up" of synthetic genomes and in low and high-throughput genome engineering have paved the way for engineering on the genome-wide scale. One of the key goals of genome engineering is the construction of minimal genomes consisting solely of essential genes (genes indispensable for survival of living organisms). Besides serving as a toolbox to understand the universal principles of life, the cell encoded by minimal genome could be used to build a stringently controlled "cell factory" with a desired phenotype. This review provides an update on recent advances in the genome-scale engineering with particular emphasis on the engineering of minimal genomes. Furthermore, it presents an ongoing discussion to the scientific community for better suitability of minimal or robust cells for industrial applications. PMID:25578717

  15. Versatile strategy for controlling the specificity and activity of engineered T cells.

    Science.gov (United States)

    Ma, Jennifer S Y; Kim, Ji Young; Kazane, Stephanie A; Choi, Sei-Hyun; Yun, Hwa Young; Kim, Min Soo; Rodgers, David T; Pugh, Holly M; Singer, Oded; Sun, Sophie B; Fonslow, Bryan R; Kochenderfer, James N; Wright, Timothy M; Schultz, Peter G; Young, Travis S; Kim, Chan Hyuk; Cao, Yu

    2016-01-26

    The adoptive transfer of autologous T cells engineered to express a chimeric antigen receptor (CAR) has emerged as a promising cancer therapy. Despite impressive clinical efficacy, the general application of current CAR-T--cell therapy is limited by serious treatment-related toxicities. One approach to improve the safety of CAR-T cells involves making their activation and proliferation dependent upon adaptor molecules that mediate formation of the immunological synapse between the target cancer cell and T-cell. Here, we describe the design and synthesis of structurally defined semisynthetic adaptors we refer to as "switch" molecules, in which anti-CD19 and anti-CD22 antibody fragments are site-specifically modified with FITC using genetically encoded noncanonical amino acids. This approach allows the precise control over the geometry and stoichiometry of complex formation between CD19- or CD22-expressing cancer cells and a "universal" anti-FITC-directed CAR-T cell. Optimization of this CAR-switch combination results in potent, dose-dependent in vivo antitumor activity in xenograft models. The advantage of being able to titrate CAR-T-cell in vivo activity was further evidenced by reduced in vivo toxicity and the elimination of persistent B-cell aplasia in immune-competent mice. The ability to control CAR-T cell and cancer cell interactions using intermediate switch molecules may expand the scope of engineered T-cell therapy to solid tumors, as well as indications beyond cancer therapy. PMID:26759368

  16. Microfluidic Buffer Exchange for Interference-free Micro/Nanoparticle Cell Engineering.

    Science.gov (United States)

    Tay, Hui Min; Yeo, David C; Wiraja, Christian; Xu, Chenjie; Hou, Han Wei

    2016-01-01

    Engineering cells with active-ingredient-loaded micro/nanoparticles (NPs) is becoming an increasingly popular method to enhance native therapeutic properties, enable bio imaging and control cell phenotype. A critical yet inadequately addressed issue is the significant number of particles that remain unbound after cell labeling which cannot be readily removed by conventional centrifugation. This leads to an increase in bio imaging background noise and can impart transformative effects onto neighboring non-target cells. In this protocol, we present an inertial microfluidics-based buffer exchange strategy termed as Dean Flow Fractionation (DFF) to efficiently separate labeled cells from free NPs in a high throughput manner. The developed spiral microdevice facilitates continuous collection (>90% cell recovery) of purified cells (THP-1 and MSCs) suspended in new buffer solution, while achieving >95% depletion of unbound fluorescent dye or dye-loaded NPs (silica or PLGA). This single-step, size-based cell purification strategy enables high cell processing throughput (10(6) cells/min) and is highly useful for large-volume cell purification of micro/nanoparticle engineered cells to achieve interference-free clinical application. PMID:27500904

  17. Bioreactor systems for tissue engineering II. Strategies for the expansion and directed differentiation of stem cells

    Energy Technology Data Exchange (ETDEWEB)

    Kasper, Cornelia [Hannover Univ. (Germany). Inst. fuer Technische Chemie; Griensven, Martijn van [Ludwig Boltzmann Institut fuer Klinische und Experimentelle Traumatologie, Wien (Austria); Poertner, Ralf (eds.) [Technische Univ. Hamburg-Harburg (Germany). Inst. Biotechnologie und Verfahrenstechnik

    2010-07-01

    Alternative Sources of Adult Stem Cells: Human Amniotic Membrane, by S. Wolbank, M. van Griensven, R. Grillari-Voglauer, and A. Peterbauer-Scherb; - Mesenchymal Stromal Cells Derived from Human Umbilical Cord Tissues: Primitive Cells with Potential for Clinical and Tissue Engineering Applications, by P. Moretti, T. Hatlapatka, D. Marten, A. Lavrentieva, I. Majore, R. Hass and C. Kasper; - Isolation, Characterization, Differentiation, and Application of Adipose-Derived Stem Cells, by J. W. Kuhbier, B. Weyand, C. Radtke, P. M. Vogt, C. Kasper and K. Reimers; - Induced Pluripotent Stem Cells: Characteristics and Perspectives, by T. Cantz and U. Martin; - Induced Pluripotent Stem Cell Technology in Regenerative Medicine and Biology, by D. Pei, J. Xu, Q. Zhuang, H.-F. Tse and M. A. Esteban; - Production Process for Stem Cell Based Therapeutic Implants: Expansion of the Production Cell Line and Cultivation of Encapsulated Cells, by C. Weber, S. Pohl, R. Poertner, P. Pino-Grace, D. Freimark, C. Wallrapp, P. Geigle and P. Czermak; - Cartilage Engineering from Mesenchymal Stem Cells, by C. Goepfert, A. Slobodianski, A.F. Schilling, P. Adamietz and R. Poertner; - Outgrowth Endothelial Cells: Sources, Characteristics and Potential Applications in Tissue Engineering and Regenerative Medicine, by S. Fuchs, E. Dohle, M. Kolbe, C. J. Kirkpatrick; - Basic Science and Clinical Application of Stem Cells in Veterinary Medicine, by I. Ribitsch, J. Burk, U. Delling, C. Geissler, C. Gittel, H. Juelke, W. Brehm; - Bone Marrow Stem Cells in Clinical Application: Harnessing Paracrine Roles and Niche Mechanisms, by R. M. El Backly, R. Cancedda; - Clinical Application of Stem Cells in the Cardiovascular System, C. Stamm, K. Klose, Y.-H. Choi. (orig.)

  18. Cartilage tissue engineering: towards a biomaterial-assisted mesenchymal stem cell therapy

    Science.gov (United States)

    Vinatier, Claire; Bouffi, Carine; Merceron, Christophe; Gordeladze, Jan; Brondello, Jean-Marc; Jorgensen, Christian; Weiss, Pierre; Guicheux, Jérôme; Noël, Danièle

    2009-01-01

    Injuries to articular cartilage are one of the most challenging issues of musculoskeletal medicine due to the poor intrinsic ability of this tissue for repair. Despite progress in orthopaedic surgery, the lack of efficient modalities of treatment for large chondral defects has prompted research on tissue engineering combining chondrogenic cells, scaffold materials and environmental factors. The aim of this review is to focus on the recent advances made in exploiting the potentials of cell therapy for cartilage engineering. These include: 1) defining the best cell candidates between chondrocytes or multipotent progenitor cells, such as multipotent mesenchymal stromal cells (MSC), in terms of readily available sources for isolation, expansion and repair potential; 2) engineering biocompatible and biodegradable natural or artificial matrix scaffolds as cell carriers, chondrogenic factors releasing factories and supports for defect filling, 3) identifying more specific growth factors and the appropriate scheme of application that will promote both chondrogenic differentiation and then maintain the differentiated phenotype overtime and 4) evaluating the optimal combinations that will answer to the functional demand placed upon cartilage tissue replacement in animal models and in clinics. Finally, some of the major obstacles generally encountered in cartilage engineering are discussed as well as future trends to overcome these limiting issues for clinical applications. PMID:19804369

  19. Effect of Electrospun Mesh Diameter, Mesh Alignment, and Mechanical Stretch on Bone Marrow Stromal Cells for Ligament Tissue Engineering

    OpenAIRE

    Bashur, Christopher Alan

    2009-01-01

    The overall goal of this research project is to develop methods for producing a tissue engineered ligament. The envisioned tissue engineering strategy involves three steps: seeding bone marrow stromal cells (BMSCs) onto electrospun scaffolds, processing them into cords that allow cell infiltration, and conditioning them with uniaxial cyclic stretch. These steps were addressed in three complimentary studies to establish new methods to engineer a tissue with ligament-like cells depositing org...

  20. The use of hTERT-immortalized cells in tissue engineering

    DEFF Research Database (Denmark)

    Kassem, Moustapha; Abdallah, Basem; Yu, Zentao;

    2004-01-01

    The use of human telomerase reverse transcriptase (hTERT)-immortalized cells in tissue engineering protocols is a potentially important application of telomere biology. Several human cell types have been created that overexpress the hTERT gene with enhanced telomerase activity, extended life span...... and maintained or even improved functional activities. Furthermore, some studies have employed the telomerized cells in tissue engineering protocols with very good results. However, high telomerase activity allows extensive cell proliferation that may be associated with genomic instability and risk...... for cell transformation. Thus, safety issues should be studied carefully before using the telomerized tissues in the clinic. Alternatively, the development of conditional or intermittent telomerase activation protocols is needed....

  1. Environmental parameters influence non-viral transfection of human mesenchymal stem cells for tissue engineering applications.

    Science.gov (United States)

    King, William J; Kouris, Nicholas A; Choi, Siyoung; Ogle, Brenda M; Murphy, William L

    2012-03-01

    Non-viral transfection is a promising technique that could be used to increase the therapeutic potential of stem cells. The purpose of this study was to explore practical culture parameters of relevance in potential human mesenchymal stem cell (hMSC) clinical and tissue engineering applications, including type of polycationic transfection reagent, N/P ratio and dose of polycation/pDNA polyplexes, cell passage number, cell density and cell proliferation. The non-viral transfection efficiency was significantly influenced by N/P ratio, polyplex dose, cell density and cell passage number. hMSC culture conditions that inhibited cell division also decreased transfection efficiency, suggesting that strategies to promote hMSC proliferation may be useful to enhance transfection efficiency in future tissue engineering studies. Non-viral transfection treatments influenced hMSC phenotype, including the expression level of the hMSC marker CD105 and the ability of hMSCs to differentiate down the osteogenic and adipogenic lineages. The parameters found here to promote hMSC transfection efficiency, minimize toxicity and influence hMSC phenotype may be instructive in future non-viral transfection studies and tissue engineering applications. PMID:22277991

  2. Proteomics in Cell Culture: From Genomics to Combined ‘Omics for Cell Line Engineering and Bioprocess Development

    DEFF Research Database (Denmark)

    Heffner, Kelley; Kaas, Christian Schrøder; Kumar, Amit;

    2015-01-01

    in media development and cell line engineering to improve growth or productivity, delay the onset of apoptosis, or utilize nutrients efficiently. Mass-spectrometry based and other proteomics methods can provide for the detection of thousands of proteins from cell culture and bioinformatics analysis...... protein production has increased significantly because proteomics can track changes in protein levels for different cell lines over time, which can be advantageous for bioprocess development and optimization. Specifically, the identification of proteins that affect cell culture processes can aid efforts...

  3. Engineering Synthetic Gene Circuits in Living Cells with CRISPR Technology.

    Science.gov (United States)

    Jusiak, Barbara; Cleto, Sara; Perez-Piñera, Pablo; Lu, Timothy K

    2016-07-01

    One of the goals of synthetic biology is to build regulatory circuits that control cell behavior, for both basic research purposes and biomedical applications. The ability to build transcriptional regulatory devices depends on the availability of programmable, sequence-specific, and effective synthetic transcription factors (TFs). The prokaryotic clustered regularly interspaced short palindromic repeat (CRISPR) system, recently harnessed for transcriptional regulation in various heterologous host cells, offers unprecedented ease in designing synthetic TFs. We review how CRISPR can be used to build synthetic gene circuits and discuss recent advances in CRISPR-mediated gene regulation that offer the potential to build increasingly complex, programmable, and efficient gene circuits in the future. PMID:26809780

  4. A Dual Receptor and Reporter for Multi-Modal Cell Surface Engineering.

    Science.gov (United States)

    Luo, Wei; Westcott, Nathan; Dutta, Debjit; Pulsipher, Abigail; Rogozhnikov, Dmitry; Chen, Jean; Yousaf, Muhammad N

    2015-10-16

    The rapid development of new small molecule drugs, nanomaterials, and genetic tools to modulate cellular function through cell surface manipulation has revolutionized the diagnosis, study, and treatment of disorders in human health. Since the cell membrane is a selective gateway barrier that serves as the first line of defense/offense and communication to its environment, new approaches that molecularly engineer or tailor cell membrane surfaces would allow for a new era in therapeutic design, therapeutic delivery, complex coculture tissue construction, and in situ imaging probe tracking technologies. In order to develop the next generation of multimodal therapies, cell behavior studies, and biotechnologies that focus on cell membrane biology, new tools that intersect the fields of chemistry, biology, and engineering are required. Herein, we develop a liposome fusion and delivery strategy to present a novel dual receptor and reporter system at cell surfaces without the use of molecular biology or metabolic biosynthesis. The cell surface receptor is based on bio-orthogonal functional groups that can conjugate a range of ligands while simultaneously reporting the conjugation through the emission of fluorescence. We demonstrate this dual receptor and reporter system by conjugating and tracking various cell surface ligands for temporal control of cell fluorescent signaling, cell-cell interaction, and tissue assembly construction. PMID:26204094

  5. Dendritic cells engineered to express defined allo-HLA peptide complexes induce antigen-specific cytotoxic T cells efficiently killing tumour cells

    DEFF Research Database (Denmark)

    Stronen, E; Abrahamsen, I W; Gaudernack, G; Wälchli, S; Munthe, E; Buus, S; Johansen, F-E; Lund-Johansen, F; Olweus, J

    2009-01-01

    , efficiently present externally loaded peptides from the antigen, Melan-A/MART-1 to T cells from HLA-A*0201-negative donors. CD8(+) T cells binding HLA-A*0201/MART-1 pentamers were detected already after 12 days of co-culture in 11/11 donors. The majority of cells from pentamer(+) cell lines were CTL and...... efficiently killed HLA-A*0201(+) melanoma cells, whilst sparing HLA-A*0201(+) B-cells. Allo-restricted CTL specific for peptides from the leukaemia-associated antigens CD33 and CD19 were obtained with comparable efficiency. Collectively, the results show that dendritic cells engineered to express defined allo...

  6. Broadband SHF Direction-Finder

    Directory of Open Access Journals (Sweden)

    S. Radionov

    2008-06-01

    Full Text Available The original design of the compact broadband direction-finder is presented in this paper. The cylindrical monopole antenna serves as a primary source of the reflector- type antenna. "Zero-amplitude" technique is used for bearing the SHF sources. The model experiments with the proposed direction-finder prototype in the frequency band 6 GHz - 11 GHz have been carried out.

  7. Broadband Loaded Cylindrical Monopole Antenna

    OpenAIRE

    Boucher, Solene; Sharaiha, Ala; Potier, Patrick

    2013-01-01

    Ahstract-A broadband printed monopole antenna based on the variation of the conductivity along its length is proposed .. The result indicates that a non-monotonous repartition provides interesting performances in terms of impedance bandwidth but also concerning antenna gain. The achievement of the method is demonstrated through its application, using the carbon fibers to perform this conductivity variation. Monopole antenna presents a large impedance bandwidth of 123% with an interesting gain...

  8. Genetically engineered dendritic cell-based cancer vaccines

    Czech Academy of Sciences Publication Activity Database

    Bubeník, Jan

    2001-01-01

    Roč. 18, č. 3 (2001), s. 475-478. ISSN 1019-6439 R&D Projects: GA MZd NC5526 Keywords : dendritic cells * tumour vaccines Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.330, year: 2001

  9. Construction of tissue-engineered heart valves by using decellularized scaffolds and endothelial progenitor cells

    Institute of Scientific and Technical Information of China (English)

    FANG Ning-tao; XIE Shang-zhe; WANG Song-mei; GAO Hong-yang; WU Chun-gen; PAN Luan-feng

    2007-01-01

    Background Tissue-engineered heart valves have the potential to overcome the limitations of present heart valve replacements. This study was designed to develop a tissue engineering heart valve by using human umbilical cord blood-derived endothelial progenitor cells (EPCs) and decellularized valve scaffolds.Methods Decellularized valve scaffolds were prepared from fresh porcine heart valves. EPCs were isolated from fresh human umbilical cord blood by density gradient centrifugation, cultured for 3 weeks in EGM-2-MV medium, by which time the resultant cell population became endothelial in nature, as assessed by immunofluorescent staining. EPC-derived endothelial cells were seeded onto the decellularized scaffold at 3 × 106 cells/cm2 and cultured under static conditions for 7 days. Proliferation of the seeded cells on the scaffolds was detected using the MTT assay. Tissue-engineered heart valves were analyzed by HE staining, immunofluorescent staining and scanning electron microscopy. The anti-thrombogenic function of the endothelium on the engineered heart valves was evaluated by platelet adhesion experiments and reverse transcription-polymerase chain reaction (RT-PCR) analysis for the expression of endothelial nitric oxide synthase (eNOS) and tissue-type plasminogen activator (t-PA).Results EPC-derived endothelial cells showed a histolytic cobblestone morphology, expressed specific markers of the endothelial cell lineage including von Willebrand factor (vWF) and CD31, bound a human endothelial cell-specific lectin,Ulex Europaeus agglutinin-1 (UEA-1), and took up Dil-labeled low density lipoprotein (Dil-Ac-LDL). After seeding on the decellularized scaffold, the cells showed excellent metabolic activity and proliferation. The cells formed confluent endothelial monolayers atop the decellularized matrix, as assessed by HE staining and immunostaining for vWF and CD31. Scanning electron microscopy demonstrated the occurrence of tight junctions between cells forming the

  10. Artificial membrane-binding proteins stimulate oxygenation of stem cells during engineering of large cartilage tissue

    Science.gov (United States)

    Armstrong, James P. K.; Shakur, Rameen; Horne, Joseph P.; Dickinson, Sally C.; Armstrong, Craig T.; Lau, Katherine; Kadiwala, Juned; Lowe, Robert; Seddon, Annela; Mann, Stephen; Anderson, J. L. Ross; Perriman, Adam W.; Hollander, Anthony P.

    2015-06-01

    Restricted oxygen diffusion can result in central cell necrosis in engineered tissue, a problem that is exacerbated when engineering large tissue constructs for clinical application. Here we show that pre-treating human mesenchymal stem cells (hMSCs) with synthetic membrane-active myoglobin-polymer-surfactant complexes can provide a reservoir of oxygen capable of alleviating necrosis at the centre of hyaline cartilage. This is achieved through the development of a new cell functionalization methodology based on polymer-surfactant conjugation, which allows the delivery of functional proteins to the hMSC membrane. This new approach circumvents the need for cell surface engineering using protein chimerization or genetic transfection, and we demonstrate that the surface-modified hMSCs retain their ability to proliferate and to undergo multilineage differentiation. The functionalization technology is facile, versatile and non-disruptive, and in addition to tissue oxygenation, it should have far-reaching application in a host of tissue engineering and cell-based therapies.

  11. Recent Progress on Systems and Synthetic Biology Approaches to Engineer Fungi As Microbial Cell Factories.

    Science.gov (United States)

    Amores, Gerardo Ruiz; Guazzaroni, María-Eugenia; Arruda, Letícia Magalhães; Silva-Rocha, Rafael

    2016-04-01

    Filamentous fungi are remarkable organisms naturally specialized in deconstructing plant biomass and this feature has a tremendous potential for biofuel production from renewable sources. The past decades have been marked by a remarkable progress in the genetic engineering of fungi to generate industry-compatible strains needed for some biotech applications. In this sense, progress in this field has been marked by the utilization of high-throughput techniques to gain deep understanding of the molecular machinery controlling the physiology of these organisms, starting thus the Systems Biology era of fungi. Additionally, genetic engineering has been extensively applied to modify wellcharacterized promoters in order to construct new expression systems with enhanced performance under the conditions of interest. In this review, we discuss some aspects related to significant progress in the understating and engineering of fungi for biotechnological applications, with special focus on the construction of synthetic promoters and circuits in organisms relevant for industry. Different engineering approaches are shown, and their potential and limitations for the construction of complex synthetic circuits in these organisms are examined. Finally, we discuss the impact of engineered promoter architecture in the single-cell behavior of the system, an often-neglected relationship with a tremendous impact in the final performance of the process of interest. We expect to provide here some new directions to drive future research directed to the construction of high-performance, engineered fungal strains working as microbial cell factories. PMID:27226765

  12. Interface engineering for efficient fullerene-free organic solar cells

    International Nuclear Information System (INIS)

    We demonstrate the role of zinc oxide (ZnO) morphology and addition of an acceptor interlayer to achieve high efficiency fullerene-free bulk heterojunction inverted organic solar cells. Nanopatterning of the ZnO buffer layer enhances the effective light absorption in the active layer, and the insertion of a twisted perylene acceptor layer planarizes and decreases the electron extraction barrier. Along with an increase in current homogeneity, the reduced work function difference and selective transport of electrons prevent the accumulation of charges and decrease the electron-hole recombination at the interface. These factors enable an overall increase of efficiency to 4.6%, which is significant for a fullerene-free solution-processed organic solar cell

  13. Interface engineering for efficient fullerene-free organic solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Shivanna, Ravichandran; Narayan, K. S., E-mail: rajaram@jncasr.ac.in, E-mail: narayan@jncasr.ac.in [Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064 (India); Rajaram, Sridhar, E-mail: rajaram@jncasr.ac.in, E-mail: narayan@jncasr.ac.in [International Centre for Materials Science, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064 (India)

    2015-03-23

    We demonstrate the role of zinc oxide (ZnO) morphology and addition of an acceptor interlayer to achieve high efficiency fullerene-free bulk heterojunction inverted organic solar cells. Nanopatterning of the ZnO buffer layer enhances the effective light absorption in the active layer, and the insertion of a twisted perylene acceptor layer planarizes and decreases the electron extraction barrier. Along with an increase in current homogeneity, the reduced work function difference and selective transport of electrons prevent the accumulation of charges and decrease the electron-hole recombination at the interface. These factors enable an overall increase of efficiency to 4.6%, which is significant for a fullerene-free solution-processed organic solar cell.

  14. Can Engineered “Designer” T Cells Outsmart Chronic Hepatitis B?

    Science.gov (United States)

    Protzer, U.; Abken, H.

    2010-01-01

    More than 350 million people worldwide are persistently infected with human heptatitis B virus (HBV) and at risk to develop liver cirrhosis and hepatocellular carcinoma making long-term treatment necessary. While a vaccine is available and new antiviral drugs are being developed, elimination of persistently infected cells is still a major issue. Recent efforts in adoptive cell therapy are experimentally exploring immunotherapeutic elimination of HBV-infected cells by means of a biological attack with genetically engineered “designer” T cells. PMID:21188203

  15. Can Engineered “Designer” T Cells Outsmart Chronic Hepatitis B?

    Directory of Open Access Journals (Sweden)

    U. Protzer

    2010-01-01

    Full Text Available More than 350 million people worldwide are persistently infected with human heptatitis B virus (HBV and at risk to develop liver cirrhosis and hepatocellular carcinoma making long-term treatment necessary. While a vaccine is available and new antiviral drugs are being developed, elimination of persistently infected cells is still a major issue. Recent efforts in adoptive cell therapy are experimentally exploring immunotherapeutic elimination of HBV-infected cells by means of a biological attack with genetically engineered “designer” T cells.

  16. Construction of tissue-engineered cartilage using human placenta-derived stem cells

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Human placenta-derived stem cells (hPDSCs) were isolated by trypsinization and further induced into cartilage cells in vitro.The engineered cartilage was constructed by combining hPDSCs with collagen sponge and the cartilage formation was observed by implantation into nude mice.Results showed that hPDSCs featured mesenchymal stem cells and maintained proliferation in vitro for over 30 passages while remaining undifferentiated.All results indicated that hPDSCs have the potential to differentiate into functional cartilage cells in vitro when combined with collagen sponge,which provided experimental evidence for prospective clinical application.

  17. Broadband solar absorption enhancement via periodic nanostructuring of electrodes.

    KAUST Repository

    Adachi, Michael M

    2013-10-14

    Solution processed colloidal quantum dot (CQD) solar cells have great potential for large area low-cost photovoltaics. However, light utilization remains low mainly due to the tradeoff between small carrier transport lengths and longer infrared photon absorption lengths. Here, we demonstrate a bottom-illuminated periodic nanostructured CQD solar cell that enhances broadband absorption without compromising charge extraction efficiency of the device. We use finite difference time domain (FDTD) simulations to study the nanostructure for implementation in a realistic device and then build proof-of-concept nanostructured solar cells, which exhibit a broadband absorption enhancement over the wavelength range of λ = 600 to 1,100 nm, leading to a 31% improvement in overall short-circuit current density compared to a planar device containing an approximately equal volume of active material. Remarkably, the improved current density is achieved using a light-absorber volume less than half that typically used in the best planar devices.

  18. Broadband Dielectric Spectroscopy on Human Blood

    CERN Document Server

    Wolf, M; Lunkenheimer, P; Loidl, A

    2011-01-01

    Dielectric spectra of human blood reveal a rich variety of dynamic processes. Achieving a better characterization and understanding of these processes not only is of academic interest but also of high relevance for medical applications as, e.g., the determination of absorption rates of electromagnetic radiation by the human body. The dielectric properties of human blood are studied using broadband dielectric spectroscopy, systematically investigating the dependence on temperature and hematocrit value. By covering a frequency range from 1 Hz to 40 GHz, information on all the typical dispersion regions of biological matter is obtained. We find no evidence for a low-frequency relaxation (alpha-relaxation) caused, e.g., by counterion diffusion effects as reported for some types of biological matter. The analysis of a strong Maxwell-Wagner relaxation arising from the polarization of the cell membranes in the 1-100 MHz region (beta-relaxation) allows for the test of model predictions and the determination of variou...

  19. Tissue engineering, stem cells, cloning, and parthenogenesis: new paradigms for therapy

    OpenAIRE

    Hipp, Jason; Atala, Anthony

    2004-01-01

    Patients suffering from diseased and injured organs may be treated with transplanted organs. However, there is a severe shortage of donor organs which is worsening yearly due to the aging population. Scientists in the field of tissue engineering apply the principles of cell transplantation, materials science, and bioengineering to construct biological substitutes that will restore and maintain normal function in diseased and injured tissues. Both therapeutic cloning (nucleus from a donor cell...

  20. Engineering tubular bone using mesenchymal stem cell sheets and coral particles

    Energy Technology Data Exchange (ETDEWEB)

    Geng, Wenxin [Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, College of Life Science, Northwest University, No.229 North Taibai Road, Xi’an 710069 (China); Ma, Dongyang [Department of Oral and Maxillofacial Surgery, Lanzhou General Hospital, Lanzhou Command of PLA, BinHe 333 South Road, Lanzhou 730052 (China); Yan, Xingrong; Liu, Liangqi; Cui, Jihong; Xie, Xin; Li, Hongmin [Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, College of Life Science, Northwest University, No.229 North Taibai Road, Xi’an 710069 (China); Chen, Fulin, E-mail: chenfl@nwu.edu.cn [Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, College of Life Science, Northwest University, No.229 North Taibai Road, Xi’an 710069 (China)

    2013-04-19

    Highlights: • We developed a novel engineering strategy to solve the limitations of bone grafts. • We fabricated tubular constructs using cell sheets and coral particles. • The composite constructs showed high radiological density and compressive strength. • These characteristics were similar to those of native bone. -- Abstract: The development of bone tissue engineering has provided new solutions for bone defects. However, the cell-scaffold-based approaches currently in use have several limitations, including low cell seeding rates and poor bone formation capacity. In the present study, we developed a novel strategy to engineer bone grafts using mesenchymal stem cell sheets and coral particles. Rabbit bone marrow mesenchymal stem cells were continuously cultured to form a cell sheet with osteogenic potential and coral particles were integrated into the sheet. The composite sheet was then wrapped around a cylindrical mandrel to fabricate a tubular construct. The resultant tubular construct was cultured in a spinner-flask bioreactor and subsequently implanted into a subcutaneous pocket in a nude mouse for assessment of its histological characteristics, radiological density and mechanical property. A similar construct assembled from a cell sheet alone acted as a control. In vitro observations demonstrated that the composite construct maintained its tubular shape, and exhibited higher radiological density, compressive strength and greater extracellular matrix deposition than did the control construct. In vivo experiments further revealed that new bone formed ectopically on the composite constructs, so that the 8-week explants of the composite sheets displayed radiological density similar to that of native bone. These results indicate that the strategy of using a combination of a cell sheet and coral particles has great potential for bone tissue engineering and repairing bone defects.

  1. Cardiovascular tissue engineering and regeneration based on adipose tissue-derived stem/stromal cells

    OpenAIRE

    Parvizi, Mojtaba

    2016-01-01

    Currently, the pre-clinical field is rapidly progressing in search of new therapeutic modalities that replace or complement current medication to treat cardiovascular disease. Among these are the single or combined use of stem cells, biomaterials and instructive factors, which together form the triad of tissue engineering and regenerative medicine. Stem cell therapy is a promising approach for repair, remodeling and even regenerate tissue of otherwise irreparable damage, such as after myocard...

  2. Biosynthesis and characterization of a novel genetically engineered polymer for targeted gene transfer to cancer cells

    OpenAIRE

    Canine, Brenda F.; Wang, Yuhua; Hatefi, Arash

    2009-01-01

    A novel multi-domain biopolymer was designed and genetically engineered with the purpose to target and transfect cancer cells. The biopolymer contains at precise locations: 1) repeating units of arginine and histidine to condense pDNA and lyse endosome membranes, 2) a HER2 targeting affibody to target cancer cells, 3) a pH responsive fusogenic peptide to destabilize endosome membranes and enhance endosomolytic activity of histidine residues, and 4) a nuclear localization signal to enhance tra...

  3. Engineering tubular bone using mesenchymal stem cell sheets and coral particles

    International Nuclear Information System (INIS)

    Highlights: • We developed a novel engineering strategy to solve the limitations of bone grafts. • We fabricated tubular constructs using cell sheets and coral particles. • The composite constructs showed high radiological density and compressive strength. • These characteristics were similar to those of native bone. -- Abstract: The development of bone tissue engineering has provided new solutions for bone defects. However, the cell-scaffold-based approaches currently in use have several limitations, including low cell seeding rates and poor bone formation capacity. In the present study, we developed a novel strategy to engineer bone grafts using mesenchymal stem cell sheets and coral particles. Rabbit bone marrow mesenchymal stem cells were continuously cultured to form a cell sheet with osteogenic potential and coral particles were integrated into the sheet. The composite sheet was then wrapped around a cylindrical mandrel to fabricate a tubular construct. The resultant tubular construct was cultured in a spinner-flask bioreactor and subsequently implanted into a subcutaneous pocket in a nude mouse for assessment of its histological characteristics, radiological density and mechanical property. A similar construct assembled from a cell sheet alone acted as a control. In vitro observations demonstrated that the composite construct maintained its tubular shape, and exhibited higher radiological density, compressive strength and greater extracellular matrix deposition than did the control construct. In vivo experiments further revealed that new bone formed ectopically on the composite constructs, so that the 8-week explants of the composite sheets displayed radiological density similar to that of native bone. These results indicate that the strategy of using a combination of a cell sheet and coral particles has great potential for bone tissue engineering and repairing bone defects

  4. Stem Cell Hydrogel, Jump-Starting Zika Drug Discovery, and Engineering RNA Recognition.

    Science.gov (United States)

    Kostic, Milka

    2016-08-18

    Every month the editors of Cell Chemical Biology bring you highlights of the most recent chemical biology literature that impressed them with creativity and potential for follow up work. Our August 2016 selection includes a description of hydrogels with self-tunable stiffness that are used to profile lipid metabolites during stems cell differentiation, a look at whether we can find a drug repurposing solution to Zika virus infection, and an engineered RNA recognition motif (RRM). PMID:27541191

  5. Scaffold- and Cell System-Based Bone Grafts in Tissue Engineering (Review)

    OpenAIRE

    Kuznetsova D.S.; Timashev P.S.; Bagratashvili V.N.; Zagaynova Е.V.

    2014-01-01

    The review considers the current trends in tissue engineering including maxillofacial surgery based on the use of scaffolds, autologous stem cells and bioactive substances. The authors have shown the advantages and disadvantages of basic materials used for scaffold synthesis — three-dimensional porous or fiber matrices serving as a mechanical frame for cells; among such materials there are natural polymers (collagen, cellulose, fibronectin, chitosan, alginate and agarose, fibroin), synthetic ...

  6. Chimeric Antigen Receptor-Engineered T Cells for Immunotherapy of Cancer

    Directory of Open Access Journals (Sweden)

    Marc Cartellieri

    2010-01-01

    Full Text Available CD4+ and CD8+ T lymphocytes are powerful components of adaptive immunity, which essentially contribute to the elimination of tumors. Due to their cytotoxic capacity, T cells emerged as attractive candidates for specific immunotherapy of cancer. A promising approach is the genetic modification of T cells with chimeric antigen receptors (CARs. First generation CARs consist of a binding moiety specifically recognizing a tumor cell surface antigen and a lymphocyte activating signaling chain. The CAR-mediated recognition induces cytokine production and tumor-directed cytotoxicity of T cells. Second and third generation CARs include signal sequences from various costimulatory molecules resulting in enhanced T-cell persistence and sustained antitumor reaction. Clinical trials revealed that the adoptive transfer of T cells engineered with first generation CARs represents a feasible concept for the induction of clinical responses in some tumor patients. However, further improvement is required, which may be achieved by second or third generation CAR-engrafted T cells.

  7. Pluripotency of Stem Cells from Human Exfoliated Deciduous Teeth for Tissue Engineering.

    Science.gov (United States)

    Rosa, Vinicius; Dubey, Nileshkumar; Islam, Intekhab; Min, Kyung-San; Nör, Jacques E

    2016-01-01

    Stem cells from human exfoliated deciduous teeth (SHED) are highly proliferative pluripotent cells that can be retrieved from primary teeth. Although SHED are isolated from the dental pulp, their differentiation potential is not limited to odontoblasts only. In fact, SHED can differentiate into several cell types including neurons, osteoblasts, adipocytes, and endothelial cells. The high plasticity makes SHED an interesting stem cell model for research in several biomedical areas. This review will discuss key findings about the characterization and differentiation of SHED into odontoblasts, neurons, and hormone secreting cells (e.g., hepatocytes and islet-like cell aggregates). The outcomes of the studies presented here support the multipotency of SHED and their potential to be used for tissue engineering-based therapies. PMID:27313627

  8. Pluripotency of Stem Cells from Human Exfoliated Deciduous Teeth for Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Vinicius Rosa

    2016-01-01

    Full Text Available Stem cells from human exfoliated deciduous teeth (SHED are highly proliferative pluripotent cells that can be retrieved from primary teeth. Although SHED are isolated from the dental pulp, their differentiation potential is not limited to odontoblasts only. In fact, SHED can differentiate into several cell types including neurons, osteoblasts, adipocytes, and endothelial cells. The high plasticity makes SHED an interesting stem cell model for research in several biomedical areas. This review will discuss key findings about the characterization and differentiation of SHED into odontoblasts, neurons, and hormone secreting cells (e.g., hepatocytes and islet-like cell aggregates. The outcomes of the studies presented here support the multipotency of SHED and their potential to be used for tissue engineering-based therapies.

  9. Bioethanol Production from Uncooked Raw Starch by Immobilized Surface-engineered Yeast Cells

    Science.gov (United States)

    Chen, Jyh-Ping; Wu, Kuo-Wei; Fukuda, Hideki

    Surface-engineered yeast Saccharomyces cerevisiae codisplaying Rhizopus oryzae glucoamylase and Streptococcus bovis α-amylase on the cell surface was used for direct production of ethanol from uncooked raw starch. By using 50 g/L cells during batch fermentation, ethanol concentration could reach 53 g/L in 7 days. During repeated batch fermentation, the production of ethanol could be maintained for seven consecutive cycles. For cells immobilized in loofa sponge, the concentration of ethanol could reach 42 g/L in 3 days in a circulating packed-bed bioreactor. However, the production of ethanol stopped thereafter because of limited contact between cells and starch. The bioreactor could be operated for repeated batch production of ethanol, but ethanol concentration dropped to 55% of its initial value after five cycles because of a decrease in cell mass and cell viability in the bioreactor. Adding cells to the bioreactor could partially restore ethanol production to 75% of its initial value.

  10. Pluripotency of Stem Cells from Human Exfoliated Deciduous Teeth for Tissue Engineering

    Science.gov (United States)

    Rosa, Vinicius; Dubey, Nileshkumar; Islam, Intekhab; Min, Kyung-San; Nör, Jacques E.

    2016-01-01

    Stem cells from human exfoliated deciduous teeth (SHED) are highly proliferative pluripotent cells that can be retrieved from primary teeth. Although SHED are isolated from the dental pulp, their differentiation potential is not limited to odontoblasts only. In fact, SHED can differentiate into several cell types including neurons, osteoblasts, adipocytes, and endothelial cells. The high plasticity makes SHED an interesting stem cell model for research in several biomedical areas. This review will discuss key findings about the characterization and differentiation of SHED into odontoblasts, neurons, and hormone secreting cells (e.g., hepatocytes and islet-like cell aggregates). The outcomes of the studies presented here support the multipotency of SHED and their potential to be used for tissue engineering-based therapies. PMID:27313627

  11. 3D-Printing Crystallographic Unit Cells for Learning Materials Science and Engineering

    Science.gov (United States)

    Rodenbough, Philip P.; Vanti, William B.; Chan, Siu-Wai

    2015-01-01

    Introductory materials science and engineering courses universally include the study of crystal structure and unit cells, which are by their nature highly visual 3D concepts. Traditionally, such topics are explored with 2D drawings or perhaps a limited set of difficult-to-construct 3D models. The rise of 3D printing, coupled with the wealth of…

  12. The cultivation of human multipotent mesenchymal stromal cells in clinical grade medium for bone tissue engineering

    Czech Academy of Sciences Publication Activity Database

    Pytlík, R.; Stehlík, D.; Soukup, T.; Kalbáčová, M.; Rypáček, František; Trč, T.; Mulinková, Katarína; Michnová, P.; Kideryová, L.; Živný, J.; Klener, P.Jr.; Veselá, R.; Trněný, M.; Klener, P.

    2009-01-01

    Roč. 30, č. 20 (2009), s. 3415-3427. ISSN 0142-9612 R&D Projects: GA MZd ND7448 Institutional research plan: CEZ:AV0Z40500505 Keywords : tissue engineering * multipotent mesenchymal stromal cells * human serum Subject RIV: FD - Oncology ; Hematology Impact factor: 7.365, year: 2009

  13. Analysis of the Proposed Ghana Broadband Strategy

    DEFF Research Database (Denmark)

    Williams, Idongesit; Botwe, Yvonne

    This project studied the Ghana Broadband Strategy with the aim of evaluating the recommendations in the strategy side by side the broadband development in Ghana. The researchers conducted interviews both officially and unofficially with ICT stakeholders, made observations, studied Government...... intervention policies recommended in the Ghana broadband policy is used to evaluate the broadband market to find out whether the strategy consolidates with the Strengths and opportunities of the market and whether it corrects the anomalies that necessitate the weaknesses and threats to the market....... The strategy did address some threats and weaknesses of the broadband market. It also consolidated on some strengths and opportunities of the broadband market. The researchers also discovered that a market can actually grow without a policy. But a market will grow faster if a well implemented policy is guiding...

  14. Measuring Broadband IR Irradiance in the Direct Solar Beam (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Reda, I.

    2015-03-01

    Solar and atmospheric science radiometers, e.g. pyranometers, pyrheliometers, and photovoltaic cells are calibrated with traceability to a consensus reference, which is maintained by Absolute Cavity Radiometers (ACRs). The ACR is an open cavity with no window, developed to measure extended broadband direct solar irradiance beyond the ultraviolet and infrared bands below and above 0.2 um and 50 um, respectively. On the other hand, pyranometers and pyrheliometers are developed to measure broadband shortwave irradiance from approximately 0.3 um to 3 um, while the present photovoltaic cells are limited to approximately 0.3 um to 1 um. The broadband mismatch of ACR versus such radiometers causes discrepancy in radiometers' calibration methods that has not been discussed or addressed in the solar and atmospheric science literature. Pyrgeometers are also used for solar and atmospheric science applications and are calibrated with traceability to consensus reference, yet are calibrated during nighttime only, because no consensus reference has yet been established for the daytime longwave irradiance. This poster shows a method to measure the broadband IR irradiance in the direct solar beam from 3 um to 50 um, as a first step that might be used to help develop calibration methods to address the mismatch between broadband ACR and shortwave radiometers, and the lack of a daytime reference for pyrgeometers. The irradiance was measured from sunrise to sunset for 5 days when the sun disk was cloudless; the irradiance varied from approximately 1 Wm-2 to 16 Wm-2 for solar zenith angle from 80 degrees to 16 degrees respectively; estimated uncertainty is 1.5 Wm-2.

  15. Measuring Broadband IR Irradiance in the Direct Solar Beam (Poster)

    Energy Technology Data Exchange (ETDEWEB)

    Reda, I.; Konings, J.; Xie, Y.; Dooraghi, M.; Sengupta, M.

    2015-03-01

    Solar and atmospheric science radiometers, e.g. pyranometers, pyrheliometers, and photovoltaic cells are calibrated with traceability to a consensus reference, which is maintained by Absolute Cavity Radiometers (ACRs). The ACR is an open cavity with no window, developed to measure extended broadband direct solar irradiance beyond the ultraviolet and infrared bands below and above 0.2 micrometers and 50 micrometers, respectively. On the other hand, pyranometers and pyrheliometers are developed to measure broadband shortwave irradiance from approximately 0.3 micrometers to 3 micrcometers, while the present photovoltaic cells are limited to approximately 0.3 micrometers to 1 micrometers. The broadband mismatch of ACR versus such radiometers causes discrepancy in radiometers' calibration methods that has not been discussed or addressed in the solar and atmospheric science literature. Pyrgeometers are also used for solar and atmospheric science applications and calibrated with traceability to consensus reference, yet calibrated during nighttime only, because no consensus reference has yet been established for the daytime longwave irradiance. This poster shows a method to measure the broadband IR irradiance in the direct solar beam from 3 micrometers to 50 micrometers, as first step that might be used to help develop calibration methods to address the mismatch between broadband ACR and shortwave radiometers, and the lack of a daytime reference for pyrgeometers. The irradiance was measured from sunrise to sunset for 5 days when the sun disk was cloudless; the irradiance varied from approximately 1 Wm-2 to 16 Wm-2 for solar zenith angle from 80 degres to 16 degrees respectively; estimated uncertainty is 1.5 Wm-2.

  16. A broadband-sensitive upconverter La(Ga{sub 0.5}Sc{sub 0.5})O{sub 3}:Er,Ni,Nb for crystalline silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, Yasuhiko, E-mail: takeda@mosk.tytlabs.co.jp; Mizuno, Shintaro; Luitel, Hom Nath; Tani, Toshihiko [Toyota Central Research and Development Laboratories, Inc., 41-1 Yokomichi, Nagakute, Aichi 480-1192 (Japan)

    2016-01-25

    We have developed an upconverter that significantly broadens the sensitive range, to overcome the shortcoming that conventional Er{sup 3+}-doped upconverters used for crystalline silicon solar cells can utilize only a small portion of the solar spectrum at around 1.55 μm. We have designed the combination of the sensitizers and host material to utilize photons not absorbed by silicon or Er{sup 3+} ions. Ni{sup 2+} ions have been selected as the sensitizers that absorb photons in the wavelength range between the silicon absorption edge (1.1 μm) and the Er{sup 3+} absorption band and transfer the energies to the Er{sup 3+} emitters, with La(Ga,Sc)O{sub 3} as the host material. The Ga to Sc ratio has been optimized to tune the location of the Ni{sup 2+} absorption band for sufficient energy transfer. Co-doping with Nb{sup 5+} ions is needed for charge balance to introduce divalent Ni{sup 2+} ions into the trivalent Ga{sup 3+} and Sc{sup 3+} sites. In addition to 1.45–1.58 μm photons directly absorbed by the Er{sup 3+} ions, we have demonstrated upconversion of 1.1–1.35 μm photons in the Ni{sup 2+} absorption band to 0.98 μm photons, using 10% Er, 0.5% Ni, and 0.5% Nb-doped La(Ga{sub 0.5}Sc{sub 0.5})O{sub 3}. The broadband-sensitive upconverter developed here can improve conversion efficiency of crystalline silicon solar cells more notably than conventional ones.

  17. Principles of broadband switching and networking

    CERN Document Server

    Liew, Soung C

    2010-01-01

    An authoritative introduction to the roles of switching and transmission in broadband integrated services networks Principles of Broadband Switching and Networking explains the design and analysis of switch architectures suitable for broadband integrated services networks, emphasizing packet-switched interconnection networks with distributed routing algorithms. The text examines the mathematical properties of these networks, rather than specific implementation technologies. Although the pedagogical explanations in this book are in the context of switches, many of the fundamenta

  18. Surface-engineered substrates for improved human pluripotent stem cell culture under fully defined conditions.

    Science.gov (United States)

    Saha, Krishanu; Mei, Ying; Reisterer, Colin M; Pyzocha, Neena Kenton; Yang, Jing; Muffat, Julien; Davies, Martyn C; Alexander, Morgan R; Langer, Robert; Anderson, Daniel G; Jaenisch, Rudolf

    2011-11-15

    The current gold standard for the culture of human pluripotent stem cells requires the use of a feeder layer of cells. Here, we develop a spatially defined culture system based on UV/ozone radiation modification of typical cell culture plastics to define a favorable surface environment for human pluripotent stem cell culture. Chemical and geometrical optimization of the surfaces enables control of early cell aggregation from fully dissociated cells, as predicted from a numerical model of cell migration, and results in significant increases in cell growth of undifferentiated cells. These chemically defined xeno-free substrates generate more than three times the number of cells than feeder-containing substrates per surface area. Further, reprogramming and typical gene-targeting protocols can be readily performed on these engineered surfaces. These substrates provide an attractive cell culture platform for the production of clinically relevant factor-free reprogrammed cells from patient tissue samples and facilitate the definition of standardized scale-up friendly methods for disease modeling and cell therapeutic applications. PMID:22065768

  19. The Response of Human Mesenchymal Stem Cells to Osteogenic Signals and its Impact on Bone Tissue Engineering

    NARCIS (Netherlands)

    Siddappa, Ramakrishnaiah; Fernandes, Hugo; Liu, Jun; Blitterswijk, van Clemens; Boer, de Jan

    2007-01-01

    Bone tissue engineering using human mesenchymal stem cells (hMSCs) is a multidisciplinary field that aims to treat patients with trauma, spinal fusion and large bone defects. Cell-based bone tissue engineering encompasses the isolation of multipotent hMSCs from the bone marrow of the patient, in vit

  20. Graded index and randomly oriented core-shell silicon nanowires for broadband and wide angle antireflection

    Directory of Open Access Journals (Sweden)

    P. Pignalosa

    2011-09-01

    Full Text Available Antireflection with broadband and wide angle properties is important for a wide range of applications on photovoltaic cells and display. The SiOx shell layer provides a natural antireflection from air to the Si core absorption layer. In this work, we have demonstrated the random core-shell silicon nanowires with both broadband (from 400nm to 900nm and wide angle (from normal incidence to 60º antireflection characteristics within AM1.5 solar spectrum. The graded index structure from the randomly oriented core-shell (Air/SiOx/Si nanowires may provide a potential avenue to realize a broadband and wide angle antireflection layer.

  1. Visible broadband magnetic response from Ag chiral Z-shaped nanohole array

    CERN Document Server

    Han, Chunrui

    2015-01-01

    We show that broadband magnetic response in visible range can be achieved through an Ag chiral Z-shaped nanohole array. The broadband effect is realized by incorporating multi-scaled inverted SRRs and metal/dielectric nanostrip antenna in one unit cell of only 260 nm square lattice, resulting in multiple excitations of magnetic resonances at different wavelengths. The collective modes show structure dependence and respond separately to LCP and RCP incident light. The Ag Z- and reverse-Z-shaped nanohole arrays have been experimentally realized by shadowing vapor deposition method which exhibit broadband transmission difference, in good agreement with numerical simulations.

  2. The economic impact of broadband deployment in Kentucky

    OpenAIRE

    David Shideler; Narine Badasyan; Laura Taylor

    2007-01-01

    Significant resources are being invested by government and the private sector in broadband infrastructure to increase broadband deployment and use. With a unique dataset of broadband availability (sorted by county), the authors assess whether broadband infrastructure has affected the industrial competitiveness of Kentucky counties. Their results suggest that broadband availability increases employment growth in some industries but not others.

  3. Stromal Cells in Dense Collagen Promote Cardiomyocyte and Microvascular Patterning in Engineered Human Heart Tissue.

    Science.gov (United States)

    Roberts, Meredith A; Tran, Dominic; Coulombe, Kareen L K; Razumova, Maria; Regnier, Michael; Murry, Charles E; Zheng, Ying

    2016-04-01

    Cardiac tissue engineering is a strategy to replace damaged contractile tissue and model cardiac diseases to discover therapies. Current cardiac and vascular engineering approaches independently create aligned contractile tissue or perfusable vasculature, but a combined vascularized cardiac tissue remains to be achieved. Here, we sought to incorporate a patterned microvasculature into engineered heart tissue, which balances the competing demands from cardiomyocytes to contract the matrix versus the vascular lumens that need structural support. Low-density collagen hydrogels (1.25 mg/mL) permit human embryonic stem cell-derived cardiomyocytes (hESC-CMs) to form a dense contractile tissue but cannot support a patterned microvasculature. Conversely, high collagen concentrations (density ≥6 mg/mL) support a patterned microvasculature, but the hESC-CMs lack cell-cell contact, limiting their electrical communication, structural maturation, and tissue-level contractile function. When cocultured with matrix remodeling stromal cells, however, hESC-CMs structurally mature and form anisotropic constructs in high-density collagen. Remodeling requires the stromal cells to be in proximity with hESC-CMs. In addition, cocultured cardiac constructs in dense collagen generate measurable active contractions (on the order of 0.1 mN/mm(2)) and can be paced up to 2 Hz. Patterned microvascular networks in these high-density cocultured cardiac constructs remain patent through 2 weeks of culture, and hESC-CMs show electrical synchronization. The ability to maintain microstructural control within engineered heart tissue enables generation of more complex features, such as cellular alignment and a vasculature. Successful incorporation of these features paves the way for the use of large scale engineered tissues for myocardial regeneration and cardiac disease modeling. PMID:26955856

  4. Application of Induced Pluripotent Stem Cells in Generation of a Tissue-Engineered Tooth-Like Structure

    OpenAIRE

    Wen, Yong; Wang, Fang; Zhang, Wencheng; Li, Yanhua; Yu, Meijiao; Nan, Xue; Chen, Lin; Yue, Wen; Xu, Xin; Pei, Xuetao

    2012-01-01

    Stem cells, such as adult stem cells or embryonic stem cells, are the most important seed cells employed in tooth tissue engineering. Even though dental-derived stem cells are a good source of seed cells for such procedures, they are not often used in clinical applications because of the limited supply. Induced pluripotent stem (iPS) cells, with their high proliferation and differentiation ability, are now considered a promising alternative. The objectives of this study were to assess the rol...

  5. Determining the fate of fluorescent quantum dots on surface of engineered budding S. cerevisiae cell molecular landscape

    OpenAIRE

    Chouhan, Raghuraj Singh; Qureshi, Anjum; Kolkar Mohammed, Javed Hussain Niazi

    2015-01-01

    In this study, we surface engineered living S. cerevisiae cells by decorating quantum dots (QDs) and traced the fate of QDs on molecular landscape of single mother cell through several generation times (progeny cells). The fate of QDs on cell-surface was tracked through the cellular division events using confocal microscopy and fluorescence emission profiles. The extent of cell-surface QDs distribution among the offspring was determined as the mother cell divides into daughter cells. Fluoresc...

  6. Engineered metal nanoparticles in the sub-nanomolar levels kill cancer cells

    Science.gov (United States)

    Vodyanoy, Vitaly; Daniels, Yasmine; Pustovyy, Oleg; MacCrehan, William A; Muramoto, Shin; Stan, Gheorghe

    2016-01-01

    Background Small metal nanoparticles obtained from animal blood were observed to be toxic to cultured cancer cells, whereas noncancerous cells were much less affected. In this work, engineered zinc and copper metal nanoparticles were produced from bulk metal rods by an underwater high-voltage discharge method. The metal nanoparticles were characterized by atomic force microscopy and X-ray photoelectron spectroscopy. The metal nanoparticles, with estimated diameters of 1 nm–2 nm, were determined to be more than 85% nonoxidized. A cell viability assay and high-resolution light microscopy showed that exposure of RG2, cultured rat brain glioma cancer cells, to the zinc and copper nanoparticles resulted in cell morphological changes, including decreased cell adherence, shrinking/rounding, nuclear condensation, and budding from cell bodies. The metal-induced cell injuries were similar to the effects of staurosporine, an active apoptotic reagent. The viability experiments conducted for zinc and copper yielded values of dissociation constants of 0.22±0.08 nmol/L (standard error [SE]) and 0.12±0.02 nmol/L (SE), respectively. The noncancerous astrocytes were not affected at the same conditions. Because metal nanoparticles were lethal to the cancer cells at sub-nanomolar concentrations, they are potentially important as nanomedicine. Purpose Lethal concentrations of synthetic metal nanoparticles reported in the literature are a few orders of magnitude higher than the natural, blood-isolated metal nanoparticles; therefore, in this work, engineered metal nanoparticles were examined to mimic the properties of endogenous metal nanoparticles. Materials and methods RG2, rat brain glioma cells CTX TNA2 brain rat astrocytes, obtained from the American Type Culture Collection, high-voltage discharge, atomic force microscope, X-ray photoelectron spectroscopy, high-resolution light microscopy, zeta potential measurements, and 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium

  7. Genetically engineered K cells provide sufficient insulin to correct hyperglycemia in a nude murine model

    Institute of Scientific and Technical Information of China (English)

    Yiqun Zhang; Liqing Yao; Kuntang Shen; Meidong Xu; Pinghong Zhou; Weige Yang; Xinyuan Liu; Xinyu Qin

    2008-01-01

    A gene therapy-based treatment of type 1 diabetes mellitus requires the development of a surrogate β cell that can synthesize and secrete functionally active insulin in response to physiologically relevant changes in ambient glucose levels. In this study, the murine enteroendocrine cell line STC-1 was genetically modified by stable transfection. Two clone cells were selected (STC-1-2 and STC-1-14) that secreted the highest levels of insulin among the 22 clones expressing insulin from 0 to 157.2 μIU/ml/106 cells/d. After glucose concentration in the culture medium was increased from 1 mM to 10 mM, secreted insulin rose from 40.3±0.8 to 56.3±3.2 μIU/ml (STC-1-2), and from 10.8±0.8 to 23.6±2.3 μIU/ml (STC-1-14). After STC-1-14 cells were implanted into diabetic nude mice, their blood glucose levels were reduced to normal. Body weight loss was also ameliorated. Our data suggested that genetically engineered K cells secrete active insulin in a glucose-regulated manner, and in vivo study showed that hyperglycemia could be reversed by implantation of the cells, suggesting that the use of genetically engineered K cells to express human insulin might provide a glucose-regulated approach to treat diabetic hyperglycemia.

  8. Label free cell tracking in 3D tissue engineering constructs with high resolution imaging

    Science.gov (United States)

    Smith, W. A.; Lam, K.-P.; Dempsey, K. P.; Mazzocchi-Jones, D.; Richardson, J. B.; Yang, Y.

    2014-02-01

    Within the field of tissue engineering there is an emphasis on studying 3-D live tissue structures. Consequently, to investigate and identify cellular activities and phenotypes in a 3-D environment for all in vitro experiments, including shape, migration/proliferation and axon projection, it is necessary to adopt an optical imaging system that enables monitoring 3-D cellular activities and morphology through the thickness of the construct for an extended culture period without cell labeling. This paper describes a new 3-D tracking algorithm developed for Cell-IQ®, an automated cell imaging platform, which has been equipped with an environmental chamber optimized to enable capturing time-lapse sequences of live cell images over a long-term period without cell labeling. As an integral part of the algorithm, a novel auto-focusing procedure was developed for phase contrast microscopy equipped with 20x and 40x objectives, to provide a more accurate estimation of cell growth/trajectories by allowing 3-D voxels to be computed at high spatiotemporal resolution and cell density. A pilot study was carried out in a phantom system consisting of horizontally aligned nanofiber layers (with precise spacing between them), to mimic features well exemplified in cellular activities of neuronal growth in a 3-D environment. This was followed by detailed investigations concerning axonal projections and dendritic circuitry formation in a 3-D tissue engineering construct. Preliminary work on primary animal neuronal cells in response to chemoattractant and topographic cue within the scaffolds has produced encouraging results.

  9. The experimental study of genetic engineering human neural stem cells mediated by lentivirus to express multigene

    Institute of Scientific and Technical Information of China (English)

    CAI Pei-qiang; TANG Xun; LIN Yue-qiu; Oudega Martin; SUN Guang-yun; XU Lin; YANG Yun-kang; ZHOU Tian-hua

    2006-01-01

    Objective:To explore the feasibility to construct genetic engineering human neural stem cells (hNSCs)mediated by lentivirus to express multigene in order to provide a graft source for further studies of spinal cord injury (SCI).Methods: Human neural stem cells from the brain cortex of human abortus were isolated and cultured, then gene was modified by lentivirus to express both green fluorescence protein (GFP) and rat neurotrophin-3(NT-3); the transgenic expression was detected by the methods of fluorescence microscope, dorsal root ganglion of fetal rats and slot blot.Results: Genetic engineering hNSCs were successfully constructed. All of the genetic engineering hNSCs which expressed bright green fluorescence were observed under the fluorescence microscope. The conditioned medium of transgenic hNSCs could induce neurite flourishing outgrowth from dorsal root ganglion (DRG). The genetic engineering hNSCs expressed high level NT-3 which could be detected by using slot blot.Conclusions: Genetic engineering hNSCs mediated by lentivirus can be constructed to express multigene successfully.

  10. Broadband b: scaling law of P-wave broadband radiated energy

    OpenAIRE

    Wu, Zhongliang; Kim, So G.; Gao, Yuan

    1995-01-01

    We analyzed the NEIC broadband radiated energy catalogue and found that the scaling law of earthquake energy deduced from Gutenegberg-Richter’s law is not valid in a quantitative sense. The analysis of broadband radiated energy, however, also shows a scaling law, which may be represented by a broadband b value.

  11. Cell Surface and Membrane Engineering: Emerging Technologies and Applications

    Directory of Open Access Journals (Sweden)

    Christopher T. Saeui

    2015-06-01

    Full Text Available Membranes constitute the interface between the basic unit of life—a single cell—and the outside environment and thus in many ways comprise the ultimate “functional biomaterial”. To perform the many and often conflicting functions required in this role, for example to partition intracellular contents from the outside environment while maintaining rapid intake of nutrients and efflux of waste products, biological membranes have evolved tremendous complexity and versatility. This article describes how membranes, mainly in the context of living cells, are increasingly being manipulated for practical purposes with drug discovery, biofuels, and biosensors providing specific, illustrative examples. Attention is also given to biology-inspired, but completely synthetic, membrane-based technologies that are being enabled by emerging methods such as bio-3D printers. The diverse set of applications covered in this article are intended to illustrate how these versatile technologies—as they rapidly mature—hold tremendous promise to benefit human health in numerous ways ranging from the development of new medicines to sensitive and cost-effective environmental monitoring for pathogens and pollutants to replacing hydrocarbon-based fossil fuels.

  12. Preparation and properties of microencapsulated genetically engineered bacteria cells for oral therapy of uremia

    Institute of Scientific and Technical Information of China (English)

    GAO Hong; YU Yaoting; CAI Baoli; WANG Manyan

    2004-01-01

    Microencapsulated genetically engineered bacteria cells are a novel approach of oral therapy for uremia.Klebsiella aerogenes urease genes (UreaDABCEFG) are transformed into E. coli DH5α cells through plasmid pKAU17. The transformant can use urea or ammonia as its sole nitrogen source through strain training. The urease genetically engineered bacteria cells are entrapped in polyvinyl alcohol (PVA) microcapsules, which can be used to remove urea from uremia patients. The mechanical strength of PVA microcapsules is significantly higher than that of APA microcapsules. This suggests that the problem of friability of APA can be solved in this way. The optimal conditions for the preparation of PVA microencapsulated genetically engineered bacterial cells are: polyvinyl alcohol (PVA, 2450±50)used as the carrier at a concentration 6%, the pH value of boric acid as crosslinking reagent 6.5, crosslinking time 24 h,entrapment ratio of bacteria 8%, air flow rate of the encapsulate device 3 L/min and liquid flow rate at 1 mL/10 min.The average diameter of microcapsules prepared under these optimal conditions is 20-40 mesh. Experiments in vitro showed that one hundred milligrams of wet bacterial cells in PVA microcapsules could remove 18.4 mg of urea in 4 h.

  13. Broadband tuning of optomechanical cavities

    Science.gov (United States)

    Wiederhecker, Gustavo S.; Manipatruni, Sasikanth; Lee, Sunwoo; Lipson, Michal

    2011-01-01

    We demonstrate broadband tuning of an optomechanical microcavity optical resonance by exploring the large optomechanical coupling of a double-wheel microcavity and its uniquely low mechanical stiffness. Using a pump laser with only 13 mW at telecom wavelengths we show tuning of the silicon nitride microcavity resonances over 32 nm. This corresponds to a tuning power efficiency of only 400 $\\mu$W/nm. By choosing a relatively low optical Q resonance ($\\approx$18,000) we prevent the cavity from reaching the regime of regenerative optomechanical oscillations. The static mechanical displacement induced by optical gradient forces is estimated to be as large as 60 nm.

  14. Broadband Tuning of Optomechanical Cavities

    OpenAIRE

    Wiederhecker, Gustavo S.; Manipatruni, Sasikanth; Lee, Sunwoo; Lipson, Michal

    2010-01-01

    We demonstrate broadband tuning of an optomechanical microcavity optical resonance by exploring the large optomechanical coupling of a double-wheel microcavity and its uniquely low mechanical stiffness. Using a pump laser with only 13 mW at telecom wavelengths we show tuning of the silicon nitride microcavity resonances over 32 nm. This corresponds to a tuning power efficiency of only 400 $\\mu$W/nm. By choosing a relatively low optical Q resonance ($\\approx$18,000) we prevent the cavity from ...

  15. Broadband Tuning of Optomechanical Cavities

    CERN Document Server

    Wiederhecker, Gustavo S; Lee, Sunwoo; Lipson, Michal

    2010-01-01

    We demonstrate broadband tuning of an optomechanical microcavity optical resonance by exploring the large optomechanical coupling of a double-wheel microcavity and its uniquely low mechanical stiffness. Using a pump laser with only 13 mW at telecom wavelengths we show tuning of the silicon nitride microcavity resonances over 32 nm. This corresponds to a tuning power efficiency of only 400 $\\mu$W/nm. By choosing a relatively low optical Q resonance ($\\approx$18,000) we prevent the cavity from reaching the regime of regenerative optomechanical oscillations. The static mechanical displacement induced by optical gradient forces is estimated to be as large as 60 nm.

  16. Achieving Universal Access to Broadband

    Directory of Open Access Journals (Sweden)

    Morten FALCH

    2009-01-01

    Full Text Available The paper discusses appropriate policy measures for achieving universal access to broadband services in Europe. Access can be delivered by means of many different technology solutions described in the paper. This means a greater degree of competition and affects the kind of policy measures to be applied. The paper concludes that other policy measure than the classical universal service obligation are in play, and discusses various policy measures taking the Lisbon process as a point of departure. Available policy measures listed in the paper include, universal service obligation, harmonization, demand stimulation, public support for extending the infrastructure, public private partnerships (PPP, and others.

  17. N-Glycosylation optimization of recombinant antibodies in CHO cell through process and metabolic engineering

    DEFF Research Database (Denmark)

    Fan, Yuzhou

    cell culture technology, upstream process engineering, metabolic engineering, and glycobiology into a systematic framework allow us to improve the production of recombinant therapeutic protein towards an optimal balance between quantity and quality. In the presented work, recent know-how on impact......Thanks to the recent advances in Chinese hamster ovary (CHO) “omic” revolution, the development of recombinant therapeutic protein bioprocessing using CHO cell factory started to merge with the new biological mindset called systems biology. In order to produce a CHO-derived recombinant therapeutic......, analysis, control and optimization of N-glycosylation were thoroughly reviewed. In particular, how to control and optimize N-glycosylation in CHO cells was exclusively studied. The main focus of this PhD project is to find effective approaches of modulating N-glycosylation of CHO-derived recombinant...

  18. T cell engineering as therapy for cancer and HIV: our synthetic future.

    Science.gov (United States)

    June, Carl H; Levine, Bruce L

    2015-10-19

    It is now well established that the immune system can control and eliminate cancer cells. Adoptive T cell transfer has the potential to overcome the significant limitations associated with vaccine-based strategies in patients who are often immune compromised. Application of the emerging discipline of synthetic biology to cancer, which combines elements of genetic engineering and molecular biology to create new biological structures with enhanced functionalities, is the subject of this overview. Various chimeric antigen receptor designs, manufacturing processes and study populations, among other variables, have been tested and reported in recent clinical trials. Many questions remain in the field of engineered T cells, but the encouraging response rates pave a wide road for future investigation into fields as diverse as cancer and chronic infections. PMID:26416683

  19. Making structured metals transparency for broadband and wide-incidence-angle electromagnetic waves

    Science.gov (United States)

    Fan, Renhao; Peng, Ruwen; Huang, Xianrong; Wang, Mu

    2014-03-01

    Very recently, we have demonstrated that one-dimensional metallic gratings can become transparent and completely antireflective for extremely broadband electromagnetic (EM) waves under oblique incidence. However, the oblique-incidence geometry, is inconvenient for the technological applications. To overcome this drawback, here we instead use oblique metal gratings with optimal tilt angles to achieve normal-incidence broadband transparence for EM waves. Further we use two-dimensional periodic metallic cuboids to achieve broadband and broad-angle high transmission and antireflection. By introducing such metallic cuboids arrays into silicon solar cells, we find that high performance of light trapping in the cells can be obtained with a significant enhancement of the ultimate quantum efficiency. The structured metals, which achieve broadband and broad-angle high transmission for EM waves, may have many other potential applications, such as transparent conducting panels, white-beam polarizers, and stealth objects.

  20. Broadband antireflection sub-wavelength structure of InGaP/InGaAs/Ge triple junction solar cell with composition-graded SiNx

    Science.gov (United States)

    Chung, Chen-Chen; Lo, Hsiao-Chieh; Lin, Yen-Ku; Yu, Hung-Wei; Tinh Tran, Binh; Lin, Kung-Liang; Chen, Yung Chang; Quan, Nguyen-Hong; Chang, Edward Yi; Tseng, Yuan-Chieh

    2015-05-01

    This work reports a fabrication strategy to improve the antireflective ability of a InGaP/GaAs/Ge triple-junction solar cell, by combining a nano-templating technique and a chemical-synthesis approach. SiH4 and N2 were used as ammonia-free reaction gases in a plasma-enhanced chemical vapor deposition (PECVD) to prepare Si3N4 as an original antireflective coating (ARC) layer with better chemical stability. Composition-graded SiNx was successfully integrated with sub-wavelength structure by modulating SiH4/N2 ratio during PECVD deposition, and followed by a controllable gold-nanoparticle masking technique on top of the solar cell. Finite-difference time-domain solution was employed to simulate and optimize the aspect-ratio of the ARC, under the condition of variable refractive index over a broad wavelength window, and followed by the masking technique to obtain the desired ARC dimension. This enabled a low light reflectance (advantages of structural optimization, better chemical stability and graded refractive index of the ARC. The solar cell’s performance was tested and showed great competitiveness to those of forefront studies, suggesting the feasibility of the proposed technology.

  1. Municipal Solid Waste Gasification with Solid Oxide Fuel Cells and Stirling Engine

    DEFF Research Database (Denmark)

    Rokni, Masoud

    2014-01-01

    Fuel Cell (SOFC). In the present study, a MSW gasification plant int egrated with SOFC is combined with a Stirling engine to recover the energy of the off - gases from the topping SOFC cycle. Detailed plant design is proposed and thermodynamic analysis is performed. Relevant parameters have been...... studied to optimize the plant efficiency in terms of operating conditions. Compared with modern waste incinerators with heat recovery, the gasification process integrated with SOFC and Stirling engine permits an increase in electricity output up of 50%, which means that the solid waste gasification...

  2. A review of decellularized stem cell matrix: a novel cell expansion system for cartilage tissue engineering

    OpenAIRE

    M Pei; Li JT; Shoukry, M; Y Zhang

    2011-01-01

    Cell-based therapy is a promising biological approach for the treatment of cartilage defects. Due to the small size of autologous cartilage samples available for cell transplantation in patients, cells need to be expanded to yield a sufficient cell number for cartilage repair. However, chondrocytes and adult stem cells tend to become replicatively senescent once they are expanded on conventional plastic flasks. Many studies demonstrate that the loss of cell properties is concomitant with the ...

  3. Metabolic engineering of Salmonella vaccine bacteria to boost human Vγ2Vδ2 T cell immunity.

    Science.gov (United States)

    Workalemahu, Grefachew; Wang, Hong; Puan, Kia-Joo; Nada, Mohanad H; Kuzuyama, Tomohisa; Jones, Bradley D; Jin, Chenggang; Morita, Craig T

    2014-07-15

    Human Vγ2Vδ2 T cells monitor isoprenoid metabolism by recognizing foreign (E)-4-hydroxy-3-methyl-but-2-enyl pyrophosphate (HMBPP), a metabolite in the 2-C-methyl-D-erythritol-4-phosphate pathway used by most eubacteria and apicomplexan parasites, and self isopentenyl pyrophosphate, a metabolite in the mevalonate pathway used by humans. Whereas microbial infections elicit prolonged expansion of memory Vγ2Vδ2 T cells, immunization with prenyl pyrophosphates or aminobisphosphonates elicit short-term Vγ2Vδ2 expansion with rapid anergy and deletion upon subsequent immunizations. We hypothesized that a live, attenuated bacterial vaccine that overproduces HMBPP would elicit long-lasting Vγ2Vδ2 T cell immunity by mimicking a natural infection. Therefore, we metabolically engineered the avirulent aroA(-) Salmonella enterica serovar Typhimurium SL7207 strain by deleting the gene for LytB (the downstream enzyme from HMBPP) and functionally complementing for this loss with genes encoding mevalonate pathway enzymes. LytB(-) Salmonella SL7207 had high HMBPP levels, infected human cells as efficiently as did the wild-type bacteria, and stimulated large ex vivo expansions of Vγ2Vδ2 T cells from human donors. Importantly, vaccination of a rhesus monkey with live lytB(-) Salmonella SL7207 stimulated a prolonged expansion of Vγ2Vδ2 T cells without significant side effects or anergy induction. These studies provide proof-of-principle that metabolic engineering can be used to derive live bacterial vaccines that boost Vγ2Vδ2 T cell immunity. Similar engineering of metabolic pathways to produce lipid Ags or B vitamin metabolite Ags could be used to derive live bacterial vaccine for other unconventional T cells that recognize nonpeptide Ags. PMID:24943221

  4. In-depth analysis of switchable glycerol based polymeric coatings for cell sheet engineering.

    Science.gov (United States)

    Becherer, Tobias; Heinen, Silke; Wei, Qiang; Haag, Rainer; Weinhart, Marie

    2015-10-01

    Scaffold-free cell sheet engineering using thermoresponsive substrates provides a promising alternative to conventional tissue engineering which in general employs biodegradable scaffold materials. We have previously developed a thermoresponsive coating with glycerol based linear copolymers that enables gentle harvesting of entire cell sheets. In this article we present an in-depth analysis of these thermoresponsive linear polyglycidyl ethers and their performance as coating for substrates in cell culture in comparison with commercially available poly(N-isopropylacrylamide) (PNIPAM) coated culture dishes. A series of copolymers of glycidyl methyl ether (GME) and glycidyl ethyl ether (EGE) was prepared in order to study their thermoresponsive properties in solution and on the surface with respect to the comonomer ratio. In both cases, when grafted to planar surfaces or spherical nanoparticles, the applied thermoresponsive polyglycerol coatings render the respective surfaces switchable. Protein adsorption experiments on copolymer coated planar surfaces with surface plasmon resonance (SPR) spectroscopy reveal the ability of the tested thermoresponsive coatings to be switched between highly protein resistant and adsorptive states. Cell culture experiments demonstrate that these thermoresponsive coatings allow for adhesion and proliferation of NIH 3T3 fibroblasts comparable to TCPS and faster than on PNIPAM substrates. Temperature triggered detachment of complete cell sheets from copolymer coated substrates was accomplished within minutes while maintaining high viability of the harvested cells. Thus such glycerol based copolymers present a promising alternative to PNIPAM as a thermoresponsive coating of cell culture substrates. PMID:26143602

  5. Broadband Wireline Provider Service Summary; BBRI_wirelineSum12

    Data.gov (United States)

    University of Rhode Island Geospatial Extension Program — This dataset represents the availability of broadband Internet access in Rhode Island via all wireline technologies assessed by Broadband Rhode Island. Broadband...

  6. NASA Glenn's Engine Components Research Lab, Cell 2B, Reactivated to Support the U.S. Army Research Laboratory T700 Engine Test

    Science.gov (United States)

    Beltran, Luis R.; Griffin, Thomas A.

    2004-01-01

    The U.S. Army Vehicle Technology Directorate at the NASA Glenn Research Center has been directed by their parent command, the U.S. Army Research Laboratory (ARL), to demonstrate active stall technology in a turboshaft engine as the next step in transitioning this technology to the Army and aerospace industry. Therefore, the Vehicle Technology Directorate requested the reactivation of Glenn's Engine Components Research Lab, Cell 2B, (ECRL 2B). They wanted to test a T700 engine that had been used previously for turboshaft engine research as a partnership between the Army and NASA on small turbine engine research. ECRL 2B had been placed in standby mode in 1997. Glenn's Testing Division initiated reactivation in May 2002 to support the new research effort, and they completed reactivation and improvements in September 2003.

  7. Time-lapse Imaging of Primary Preneoplastic Mammary Epithelial Cells Derived from Genetically Engineered Mouse Models of Breast Cancer

    OpenAIRE

    Nakles, Rebecca E.; Millman, Sarah L.; Cabrera, M. Carla; Johnson, Peter; Mueller, Susette; Hoppe, Philipp S.; Schroeder, Timm; Furth, Priscilla A.

    2013-01-01

    Time-lapse imaging can be used to compare behavior of cultured primary preneoplastic mammary epithelial cells derived from different genetically engineered mouse models of breast cancer. For example, time between cell divisions (cell lifetimes), apoptotic cell numbers, evolution of morphological changes, and mechanism of colony formation can be quantified and compared in cells carrying specific genetic lesions. Primary mammary epithelial cell cultures are generated from mammary glands without...

  8. Broadband Acoustic Cloak for Ultrasound Waves

    CERN Document Server

    Zhang, Shu; Fang, Nicholas

    2010-01-01

    Invisibility devices based on coordinate transformation have opened up a new field of considerable interest. Such a device is proposed to render the hidden object undetectable under the flow of light or sound, by guiding and controlling the wave path through an engineered space surrounding the object. We present here the first practical realization of a low-loss and broadband acoustic cloak for underwater ultrasound. This metamaterial cloak is constructed with a network of acoustic circuit elements, namely serial inductors and shunt capacitors. Our experiment clearly shows that the acoustic cloak can effectively bend the ultrasound waves around the hidden object, with reduced scattering and shadow. Due to the non-resonant nature of the building elements, this low loss (~6dB/m) cylindrical cloak exhibits excellent invisibility over a broad frequency range from 52 to 64 kHz in the measurements. The low visibility of the cloaked object for underwater ultrasound shed a light on the fundamental understanding of ma...

  9. 78 FR 32165 - Broadband Over Power Lines

    Science.gov (United States)

    2013-05-29

    ... has potential applications for broadband and Smart Grid uses--while protecting incumbent radio... providing for Access BPL technology--which has potential applications for broadband and Smart Grid uses... study on In-House BPL in our consideration of Access BPL interference potential. However, that...

  10. 76 FR 71892 - Broadband Over Power Lines

    Science.gov (United States)

    2011-11-21

    ... BPL technology that has potential applications for broadband and Smart Grid while protecting incumbent... providing for Access BPL technology that has potential applications for broadband and Smart Grid while... used by manufacturers of HomePlug In-House BPL equipment, it is more stringent than is necessary...

  11. Broadband antenna arrays using planar horns

    OpenAIRE

    Braude, V. B.; Sukhovetskaya, S. B.

    1997-01-01

    Broadband antennas are vitally important for various applications ranging from TV broadcasting to carrier-free ground-probing radars. We propose a microwave broadband antenna array (BAA), which may be realised using microstrip planar horns — flared end-fire radiating slot lines, known as Vivaldi-type antennas.

  12. An Assessment of Cell Culture Plate Surface Chemistry for in Vitro Studies of Tissue Engineering Scaffolds

    Directory of Open Access Journals (Sweden)

    Alexander Röder

    2015-11-01

    Full Text Available The use of biopolymers as a three dimensional (3D support structure for cell growth is a leading tissue engineering approach in regenerative medicine. Achieving consistent cell seeding and uniform cell distribution throughout 3D scaffold culture in vitro is an ongoing challenge. Traditionally, 3D scaffolds are cultured within tissue culture plates to enable reproducible cell seeding and ease of culture media change. In this study, we compared two different well-plates with different surface properties to assess whether seeding efficiencies and cell growth on 3D scaffolds were affected. Cell attachment and growth of murine calvarial osteoblast (MC3T3-E1 cells within a melt-electrospun poly-ε-caprolactone scaffold were assessed when cultured in either “low-adhesive” non-treated or corona discharged-treated well-plates. Increased cell adhesion was observed on the scaffold placed in the surface treated culture plates compared to the scaffold in the non-treated plates 24 h after seeding, although it was not significant. However, higher cell metabolic activity was observed on the bases of all well-plates than on the scaffold, except for day 21, well metabolic activity was higher in the scaffold contained in non-treated plate than the base. These results indicate that there is no advantage in using non-treated plates to improve initial cell seeding in 3D polymeric tissue engineering scaffolds, however non-treated plates may provide an improved metabolic environment for long-term studies.

  13. Customer Churn Prediction for Broadband Internet Services

    Science.gov (United States)

    Huang, B. Q.; Kechadi, M.-T.; Buckley, B.

    Although churn prediction has been an area of research in the voice branch of telecommunications services, more focused studies on the huge growth area of Broadband Internet services are limited. Therefore, this paper presents a new set of features for broadband Internet customer churn prediction, based on Henley segments, the broadband usage, dial types, the spend of dial-up, line-information, bill and payment information, account information. Then the four prediction techniques (Logistic Regressions, Decision Trees, Multilayer Perceptron Neural Networks and Support Vector Machines) are applied in customer churn, based on the new features. Finally, the evaluation of new features and a comparative analysis of the predictors are made for broadband customer churn prediction. The experimental results show that the new features with these four modelling techniques are efficient for customer churn prediction in the broadband service field.

  14. In vitro evaluation of cytotoxicity of engineered carbon nanotubes in selected human cell lines

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Xiaoke; Cook, Sean; Wang, Peng [Department of Biology, Jackson State University, P.O. Box 18540, Jackson, MS 39217 (United States); Hwang, Huey-min, E-mail: huey-min.hwang@jsums.edu [Department of Biology, Jackson State University, P.O. Box 18540, Jackson, MS 39217 (United States); Liu, Xi; Williams, Quinton L. [Department of Physics, Atmospheric Sciences and Geoscience, Jackson State University, P.O. Box 17660, Jackson, MS 39217 (United States)

    2010-03-15

    In this study, we used a systematic approach to study and compare the in vitro cytotoxicity of selected engineered carbon nanotubes (CNTs) to test cell lines including human skin keratinocytes, lung cells and lymphocytes. Results of fluorescein diacetate (FDA) uptake in T4 lymphocyte A3 cells indicated cytotoxicity caused by single-walled carbon nanotubes (SWCNTs) at concentrations of 2, 5 and 10 ppm. At 2 ppm, the SWCNT treatment group retained 71.3% viability compared to the PBS control group. At 10 ppm, cellular viability further decreased to 56.5% of the PBS control group. In the skin keratinocyte HaCaT cells and lung MSTO-211H cells, the SWCNT did not demonstrate any cytotoxicity at concentrations of 2 and 5 ppm but slightly inhibited HaCaT cells and caused significant toxicity to MSTO-211H cells at 10 ppm. Multi-walled carbon nanotube (MWCNT) testing showed significant cytotoxicity to A3 cells in a dose-dependent manner. At 10 ppm the viability of the cells decreased to 89.1% compared to the PBS control. In MSTO-211H cells, MWCNT caused significant toxicity at concentrations of 2 ppm and higher. By comparison, HaCaT cells were inhibited significantly only at 10 ppm. Overall, the test CNTs inhibited cellular viabilities in a concentration, cell type, and CNT type-dependent pattern. The viabilities of the MWCNT-impacted cells are higher than the corresponding SWCNT groups. We speculate that on a per volume basis, the greater availability of defects and contaminants for cellular interaction may contribute to the higher cytotoxicity of SWCNT in this study. The interaction between the SWCNTs and A3 lymphocytes was also observed by scanning electron microscopy. The mechanism for causing cell death in this study was attributed to apoptosis and necrosis after physical penetration by CNTs and oxidative stress via formation of reactive oxygen species.

  15. In vitro evaluation of cytotoxicity of engineered carbon nanotubes in selected human cell lines

    International Nuclear Information System (INIS)

    In this study, we used a systematic approach to study and compare the in vitro cytotoxicity of selected engineered carbon nanotubes (CNTs) to test cell lines including human skin keratinocytes, lung cells and lymphocytes. Results of fluorescein diacetate (FDA) uptake in T4 lymphocyte A3 cells indicated cytotoxicity caused by single-walled carbon nanotubes (SWCNTs) at concentrations of 2, 5 and 10 ppm. At 2 ppm, the SWCNT treatment group retained 71.3% viability compared to the PBS control group. At 10 ppm, cellular viability further decreased to 56.5% of the PBS control group. In the skin keratinocyte HaCaT cells and lung MSTO-211H cells, the SWCNT did not demonstrate any cytotoxicity at concentrations of 2 and 5 ppm but slightly inhibited HaCaT cells and caused significant toxicity to MSTO-211H cells at 10 ppm. Multi-walled carbon nanotube (MWCNT) testing showed significant cytotoxicity to A3 cells in a dose-dependent manner. At 10 ppm the viability of the cells decreased to 89.1% compared to the PBS control. In MSTO-211H cells, MWCNT caused significant toxicity at concentrations of 2 ppm and higher. By comparison, HaCaT cells were inhibited significantly only at 10 ppm. Overall, the test CNTs inhibited cellular viabilities in a concentration, cell type, and CNT type-dependent pattern. The viabilities of the MWCNT-impacted cells are higher than the corresponding SWCNT groups. We speculate that on a per volume basis, the greater availability of defects and contaminants for cellular interaction may contribute to the higher cytotoxicity of SWCNT in this study. The interaction between the SWCNTs and A3 lymphocytes was also observed by scanning electron microscopy. The mechanism for causing cell death in this study was attributed to apoptosis and necrosis after physical penetration by CNTs and oxidative stress via formation of reactive oxygen species.

  16. Wireless Broadband Communications Systems in Rural Wisconsin. Rural Research Report. Volume 19, Issue 1, Spring 2008

    Science.gov (United States)

    Schlager, Kenneth J.

    2008-01-01

    This report describes a communications system engineering planning process that demonstrates an ability to design and deploy cost-effective broadband networks in low density rural areas. The emphasis in on innovative solutions and systems optimization because of the marginal nature of rural telecommunications infrastructure investments. Otherwise,…

  17. Tissue engineering approaches for studying the effect of biochemical and physiological stimuli on cell behavior

    Science.gov (United States)

    Jimenez Vergara, Andrea Carolina

    Tissue engineering (TE) approaches have emerged as an alternative to traditional tissue and organ replacements. The aim of this work was to contribute to the understanding of the effects of cell-material and endothelial cell (EC) paracrine signaling on cell responses using poly(ethylene glycol) diacrylate (PEGDA) hydrogels as a material platform. Three TE applications were explored. First, the effect of glycosaminoglycan (GAG) identity was evaluated for vocal fold restoration. Second, the influence of GAG identity was explored and a novel approach for stable endothelialization was developed for vascular graft applications. Finally, EC paracrine signaling in the presence of cyclic stretch, and hydrophobicity and inorganic content were studied for osteogenic applications. In terms of vocal fold restoration, it was found that vocal fold fibroblast (VFF) phenotype and extracellular matrix (ECM) production were impacted by GAG identity. VFF phenotype was preserved in long-term cultured hydrogels containing high molecular weight hyaluronan (HAHMW). Furthermore, collagen I deposition, fibronectin production and smooth muscle α-actin (SM-α-actin) expression in PEG-HA, PEG-chondroitin sulfate C and PEG-heparan sulfate (HS) gels suggest that CSC and HS may be undesirable for vocal fold implants. Regarding vascular graft applications, the impact of GAG identity on smooth muscle cell (SMC) foam cell formation was explored. Results support the increasing body of literature that suggests a critical role for dermatan sulfate (DS)-bearing proteoglycans in early atherosclerosis. In addition, an approach for fabricating bi-layered tissue engineering vascular grafts (TEVGs) with stable endothelialization was validated using PEGDA as an intercellular “cementing” agent between adjacent endothelial cells (ECs). Finally, mesenchymal stem cell (MSC) differentiation toward osteogenic like cells was evaluated. ECM and cell phenotypic data showed that elevated scaffold inorganic

  18. Immunotoxicological impact of engineered nanomaterial exposure: mechanisms of immune cell modulation

    OpenAIRE

    WANG, XIAOJIA; Reece, Shaun P.; Brown, Jared M.

    2013-01-01

    Engineered nanomaterials (ENM) are increasingly being utilized in many consumer products and various medical applications thereby leading to the potentiality of increased human exposures. Assessment of the adverse effects on the immune system is an important component for evaluating the overall health and safety of ENM. Tasked with eliminating pathogens and removing cancerous cells, the immune system is constantly functioning to maintain homeostasis. Small modifications to the immune system w...

  19. Solving cell infiltration limitations of electrospun nanofiber meshes for tissue engineering applications

    OpenAIRE

    Guimarães, Ana; Martins, Albino; Pinho, Elisabete D.; Faria, Susana; Reis, R. L.; Neves, N. M.

    2010-01-01

    AIM: Utilize the dual composition strategy to increase the pore size and solve the low cell infiltration capacity on random nanofiber meshes, an intrinsic limitation of electrospun scaffolds for tissue engineering applications. MATERIALS & METHODS: Polycaprolactone and poly(ethylene oxide) solutions were electrospun simultaneously to obtain a dual composition nanofiber mesh. Selective dissolution of the poly(ethylene oxide) nanofiber fraction was performed. The biologic performance of these e...

  20. Epidermal stem cells and skin tissue engineering in hair follicle regeneration

    OpenAIRE

    Balañá, María Eugenia; Charreau, Hernán Eduardo; Leirós, Gustavo José

    2015-01-01

    The reconstitution of a fully organized and functional hair follicle from dissociated cells propagated under defined tissue culture conditions is a challenge still pending in tissue engineering. The loss of hair follicles caused by injuries or pathologies such as alopecia not only affects the patients’ psychological well-being, but also endangers certain inherent functions of the skin. It is then of great interest to find different strategies aiming to regenerate or neogenerate the hair folli...

  1. Hepatic tissue engineering: from transplantation to customized cell-based liver directed therapies from the laboratory

    OpenAIRE

    Fiegel, Henning C; Kaufmann, Peter M; Bruns, Helge; Kluth, Dietrich; Horch, Raymund E.; Vacanti, Joseph P.; Kneser, Ulrich

    2008-01-01

    Abstract Today, liver transplantation is still the only curative treatment for liver failure due to end-stage liver diseases. Donor organ shortage, high cost and the need of immunosuppressive medications are still the major limitations in the field of liver transplantation. Thus, alternative innovative cell-based liver directed therapies, for example, liver tissue engineering, are under investigation with the aim that in future an artificial liver tissue could be created and be used for the r...

  2. Characterization of Bone Marrow Mononuclear Cells on Biomaterials for Bone Tissue Engineering In Vitro

    OpenAIRE

    Dirk Henrich; René Verboket; Alexander Schaible; Kerstin Kontradowitz; Elsie Oppermann; Brune, Jan C; Christoph Nau; Simon Meier; Halvard Bonig; Ingo Marzi; Caroline Seebach

    2015-01-01

    Bone marrow mononuclear cells (BMCs) are suitable for bone tissue engineering. Comparative data regarding the needs of BMC for the adhesion on biomaterials and biocompatibility to various biomaterials are lacking to a large extent. Therefore, we evaluated whether a surface coating would enhance BMC adhesion and analyze the biocompatibility of three different kinds of biomaterials. BMCs were purified from human bone marrow aspirate samples. Beta tricalcium phosphate (β-TCP, without coating or ...

  3. Cell interaction with cellulose-based scaffolds for tissue engineering: a review

    Czech Academy of Sciences Publication Activity Database

    Bačáková, Lucie; Novotná, Katarína; Sopuch, T.; Havelka, P.

    New York: Nova Science Publishers, 2015 - (Mondal, M.), s. 341-375 ISBN 978-1-63483-553-4 R&D Projects: GA ČR(CZ) GAP108/12/1168; GA ČR(CZ) GAP108/11/1857; GA MZd(CZ) NT13297; GA TA ČR(CZ) TA04010065 Institutional support: RVO:67985823 Keywords : polysaccharides * cellulose * biomaterial * tissue engineering * regenerative medicine * cell therapy Subject RIV: EI - Biotechnology ; Bionics

  4. Preface to Special Topic: Microfluidics in cell biology and tissue engineering

    OpenAIRE

    Dokmeci, Mehmet R.; Khademhosseini, Ali

    2011-01-01

    In this special issue of Biomicrofluidics, a wide variety of applications of microfluidics to tissue engineering and cell biology are presented. The articles illustrate the benefits of using microfluidics for controlling the cellular environment in a precise yet high rate manner using minimum reagents. The topic is very timely and takes a stab at portraying a glimpse of what is to come in this exciting and emerging field of research.

  5. Design, Engineering, and Construction of Photosynthetic Microbial Cell Factories for Renewable Solar Fuel Production

    Energy Technology Data Exchange (ETDEWEB)

    Lindblad, Peter; Lindberg, Pia; Stensjoe, Karin (Photochemistry and Molecular Science, Dept. of Chemistry-Aangstroem Laboratory, Uppsala Univ., Uppsala (Sweden)), E-mail: Peter.Lindblad@kemi.uu.se; Oliveira, Paulo (Instituto de Biologia Molecular e Celular, Porto (Portugal)); Heidorn, Thorsten (Bioforsk-Norwegian Inst. for Agricultural and Environmental Research, Aas Oslo, (Norway))

    2012-03-15

    There is an urgent need to develop sustainable solutions to convert solar energy into energy carriers used in the society. In addition to solar cells generating electricity, there are several options to generate solar fuels. This paper outlines and discusses the design and engineering of photosynthetic microbial systems for the generation of renewable solar fuels, with a focus on cyanobacteria. Cyanobacteria are prokaryotic microorganisms with the same type of photosynthesis as higher plants. Native and engineered cyanobacteria have been used by us and others as model systems to examine, demonstrate, and develop photobiological H{sub 2} production. More recently, the production of carbon-containing solar fuels like ethanol, butanol, and isoprene have been demonstrated. We are using a synthetic biology approach to develop efficient photosynthetic microbial cell factories for direct generation of biofuels from solar energy. Present progress and advances in the design, engineering, and construction of such cyanobacterial cells for the generation of a portfolio of solar fuels, e.g., hydrogen, alcohols, and isoprene, are presented and discussed. Possibilities and challenges when introducing and using synthetic biology are highlighted

  6. Interface Engineering of High Efficiency Organic-Silicon Heterojunction Solar Cells.

    Science.gov (United States)

    Yang, Lixia; Liu, Yaoping; Chen, Wei; Wang, Yan; Liang, Huili; Mei, Zengxia; Kuznetsov, Andrej; Du, Xiaolong

    2016-01-13

    Insufficient interface conformity is a challenge faced in hybrid organic-silicon heterojunction solar cells because of using conventional pyramid antireflection texturing provoking the porosity of interface. In this study, we tested alternative textures, in particular rounded pyramids and inverted pyramids to compare the performance. It was remarkably improved delivering 7.61%, 8.91% and 10.04% efficiency employing conventional, rounded, and inverted pyramids, respectively. The result was interpreted in terms of gradually improving conformity of the Ag/organic/silicon interface, together with the gradually decreasing serial resistance. Altogether, the present data may guide further efforts arising the interface engineering for mastering high efficient heterojunction solar cells. PMID:26701061

  7. Broadband cloaking for flexural waves

    CERN Document Server

    Zareei, Ahmad

    2016-01-01

    The governing equation for elastic waves in flexural plates is not form invariant, and hence designing a cloak for such waves faces a major challenge. Here, we present the design of a perfect broadband cloak for flexural waves through the use of a nonlinear transformation, and by matching term-by-term the original and transformed equations. For a readily achievable flexural cloak in a physical setting, we further present an approximate adoption of our perfect cloak under more restrictive physical constraints. Through direct simulation of the governing equations, we show that this cloak, as well, maintains a consistently high cloaking efficiency over a broad range of frequencies. The methodology developed here may be used for steering waves and designing cloaks in other physical systems with non form-invariant governing equations.

  8. Interpreting Flux from Broadband Photometry

    CERN Document Server

    Brown, Peter J; Roming, Peter W A; Siegel, Michael

    2016-01-01

    We discuss the transformation of observed photometry into flux for the creation of spectral energy distributions and the computation of bolometric luminosities. We do this in the context of supernova studies, particularly as observed with the Swift spacecraft, but the concepts and techniques should be applicable to many other types of sources and wavelength regimes. Traditional methods of converting observed magnitudes to flux densities are not very accurate when applied to UV photometry. Common methods for extinction and the integration of pseudo-bolometric fluxes can also lead to inaccurate results. The sources of inaccuracy, though, also apply to other wavelengths. Because of the complicated nature of translating broad-band photometry into monochromatic flux densities, comparison between observed photometry and a spectroscopic model is best done by comparing in the natural units of the observations. We recommend that integrated flux measurements be made using a spectrum or spectral energy distribution whic...

  9. Systemic treatment with CAR-engineered T cells against PSCA delays subcutaneous tumor growth and prolongs survival of mice

    International Nuclear Information System (INIS)

    Adoptive transfer of T cells genetically engineered with a chimeric antigen receptor (CAR) has successfully been used to treat both chronic and acute lymphocytic leukemia as well as other hematological cancers. Experimental therapy with CAR-engineered T cells has also shown promising results on solid tumors. The prostate stem cell antigen (PSCA) is a protein expressed on the surface of prostate epithelial cells as well as in primary and metastatic prostate cancer cells and therefore a promising target for immunotherapy of prostate cancer. We developed a third-generation CAR against PSCA including the CD28, OX-40 and CD3 ζ signaling domains. T cells were transduced with a lentivirus encoding the PSCA-CAR and evaluated for cytokine production (paired Student’s t-test), proliferation (paired Student’s t-test), CD107a expression (paired Student’s t-test) and target cell killing in vitro and tumor growth and survival in vivo (Log-rank test comparing Kaplan-Meier survival curves). PSCA-CAR T cells exhibit specific interferon (IFN)-γ and interleukin (IL)-2 secretion and specific proliferation in response to PSCA-expressing target cells. Furthermore, the PSCA-CAR-engineered T cells efficiently kill PSCA-expressing tumor cells in vitro and systemic treatment with PSCA-CAR-engineered T cells significantly delays subcutaneous tumor growth and prolongs survival of mice. Our data confirms that PSCA-CAR T cells may be developed for treatment of prostate cancer

  10. Fuel cells science and engineering. Materials, processes, systems and technology. Vol. 2

    Energy Technology Data Exchange (ETDEWEB)

    Stolten, Detlef; Emonts, Bernd (eds.) [Forschungszentrum Juelich GmbH (DE). Inst. fuer Energieforschung (IEF), Brennstoffzellen (IEF-3)

    2012-07-01

    The second volume is divided in four parts and 19 chapters. It is structured as follows: PART V: Modeling and Simulation. Chapter 23: Messages from Analytical Modeling of Fuel Cells (Andrei Kulikovsky); 24: Stochastic Modeling of Fuel-Cell Components (Ralf Thiedmann, Gerd Gaiselmann, Werner Lehnert and Volker Schmidt); 25: Computational Fluid Dynamic Simulation Using Supercomputer Calculation Capacity (Ralf Peters and Florian Scharf); 26 Modeling Solid Oxide Fuel Cells from the Macroscale to the Nanoscale (Emily M. Ryan and Mohammad A. Khaleel); 27: Numerical Modeling of the Thermomechanically Induced Stress in Solid Oxide Fuel Cells (Murat Peksen); 28: Modeling of Molten Carbonate Fuel Cells (Peter Heidebrecht, Silvia Piewek and Kai Sundmacher); Chapter 29: High-Temperature Polymer Electrolyte Fuel-Cell Modeling (Uwe Reimer); Chapter 30: Modeling of Polymer Electrolyte Membrane Fuel-Cell Components (Yun Wang and Ken S. Chen); 31: Modeling of Polymer Electrolyte Membrane Fuel Cells and Stacks (Yun Wang and Ken S. Chen). PART VI: Balance of Plant Design and Components. Chapter 32: Principles of Systems Engineering (Ludger Blum, Ralf Peters and Remzi Can Samsun); 33: System Technology for Solid Oxide Fuel Cells (Nguyen Q. Minh); 34: Desulfurization for Fuel-Cell Systems (Joachim Pasel and Ralf Peters); 35: Design Criteria and Components for Fuel Cell Powertrains (Lutz Eckstein and Bruno Gnoerich); 36: Hybridization for Fuel Cells (Joerg Wilhelm). PART VII: Systems Verification and Market Introduction. Chapter 37: Off-Grid Power Supply and Premium Power Generation (Kerry-Ann Adamson); 38: Demonstration Projects and Market Introduction (Kristin Deason). PART VIII: Knowledge Distribution and Public Awareness. Chapter 39: A Sustainable Framework for International Collaboration: the IEA HIA and Its Strategic Plan for 2009-2015 (Mary-Rose de Valladares); 40: Overview of Fuel Cell and Hydrogen Organizations and Initiatives Worldwide (Bernd Emonts) 41: Contributions for

  11. Comparative study on seeding methods of human bone marrow stromal cells in bone tissue engineering

    Institute of Scientific and Technical Information of China (English)

    齐欣; 刘建国; 常颖; 徐莘香

    2004-01-01

    Background In general the traditional static seeding method has its limitation while the dynamic seeding method reveals its advantages over traditional static method. We compared static and dynamic seeding method for human bone marrow stromal cells (hBMSCs) in bone tissue engineering.Methods DNA assay was used for detecting the maximal initial seeding concentration for static seeding. Dynamic and static seeding methods were compared, when scaffolds were loaded with hBMSCs at this maximal initial cell seeding concentration. Histology and scanning electron microscope (SEM) were examined to evaluate the distribution of cells inside the constructs. Markers encoding osteogenic genes were measured by fluorescent RT-PCR. The protocol for dynamic seeding of hBMSCs was also investigated.Results DNA assay showed that the static maximal initial seeding concentration was lower than that in dynamic seeding. Histology and SEM showed even distribution and spread of cells in the dynamically seeded constructs, while their statically seeded counterparts showed cell aggregation.Fluorescent RT-PCR again showed stronger osteogenic potential of dynamically seeded constructs.Conclusion dynamic seeding of hBMSCs is a promising technique in bone tissue engineering.

  12. Tissue engineering by self-assembly and bio-printing of living cells

    Energy Technology Data Exchange (ETDEWEB)

    Jakab, Karoly; Marga, Francoise; Forgacs, Gabor [Department of Physics and Astronomy, University of Missouri, Columbia, MO 65211 (United States); Norotte, Cyrille [Department of Biology, University of Missouri, Columbia, MO 65211 (United States); Murphy, Keith [Organovo, Inc., 5871 Oberlin Drive, San Diego, CA 92121 (United States); Vunjak-Novakovic, Gordana, E-mail: forgacsg@missouri.ed [Department of Biomedical Engineering, Columbia University, New York, NY 10032 (United States)

    2010-06-15

    Biofabrication of living structures with desired topology and functionality requires the interdisciplinary effort of practitioners of the physical, life and engineering sciences. Such efforts are being undertaken in many laboratories around the world. Numerous approaches are pursued, such as those based on the use of natural or artificial scaffolds, decellularized cadaveric extracellular matrices and, most lately, bioprinting. To be successful in this endeavor, it is crucial to provide in vitro micro-environmental clues for the cells resembling those in the organism. Therefore, scaffolds, populated with differentiated cells or stem cells, of increasing complexity and sophistication are being fabricated. However, no matter how sophisticated scaffolds are, they can cause problems stemming from their degradation, eliciting immunogenic reactions and other a priori unforeseen complications. It is also being realized that ultimately the best approach might be to rely on the self-assembly and self-organizing properties of cells and tissues and the innate regenerative capability of the organism itself, not just simply prepare tissue and organ structures in vitro followed by their implantation. Here we briefly review the different strategies for the fabrication of three-dimensional biological structures, in particular bioprinting. We detail a fully biological, scaffoldless, print-based engineering approach that uses self-assembling multicellular units as bio-ink particles and employs early developmental morphogenetic principles, such as cell sorting and tissue fusion. (topical review)

  13. Tissue engineering by self-assembly and bio-printing of living cells

    International Nuclear Information System (INIS)

    Biofabrication of living structures with desired topology and functionality requires the interdisciplinary effort of practitioners of the physical, life and engineering sciences. Such efforts are being undertaken in many laboratories around the world. Numerous approaches are pursued, such as those based on the use of natural or artificial scaffolds, decellularized cadaveric extracellular matrices and, most lately, bioprinting. To be successful in this endeavor, it is crucial to provide in vitro micro-environmental clues for the cells resembling those in the organism. Therefore, scaffolds, populated with differentiated cells or stem cells, of increasing complexity and sophistication are being fabricated. However, no matter how sophisticated scaffolds are, they can cause problems stemming from their degradation, eliciting immunogenic reactions and other a priori unforeseen complications. It is also being realized that ultimately the best approach might be to rely on the self-assembly and self-organizing properties of cells and tissues and the innate regenerative capability of the organism itself, not just simply prepare tissue and organ structures in vitro followed by their implantation. Here we briefly review the different strategies for the fabrication of three-dimensional biological structures, in particular bioprinting. We detail a fully biological, scaffoldless, print-based engineering approach that uses self-assembling multicellular units as bio-ink particles and employs early developmental morphogenetic principles, such as cell sorting and tissue fusion. (topical review)

  14. Omnidirectional and broadband absorption enhancement from trapezoidal Mie resonators in semiconductor metasurfaces

    CERN Document Server

    Pala, Ragip A; Aydin, Koray; Atwater, Harry A

    2015-01-01

    Light trapping in planar ultrathin-film solar cells is limited due to a small number of optical modes available in the thin-film slab. A nanostructured thin-film design could surpass this limit by providing broadband increase in the local density of states in a subwavelength volume and maintaining efficient coupling of light. Here we report a broadband metasurface design, enabling efficient and broadband absorption enhancement by direct coupling of incoming light to resonant modes of subwavelength-scale Mie nanoresonators defined in the thin-film active layer. Absorption was investigated both theoretically and experimentally in prototypes consisting of lithographically patterned, two-dimensional periodic arrays of silicon nanoresonators on silica substrates. A crossed trapezoid resonator shape of rectangular cross section is used to excite broadband Mie resonances across the visible and near-IR spectra. Our numerical simulations, optical absorption measurements and photocurrent spectral response measurements ...

  15. Characteristics of a Broadband Dye Laser Using Pyrromethene and Rhodamine Dyes

    Science.gov (United States)

    Tedder, Sarah A.; Danehy, Paul M.; Wheeler, Jeffrey L.

    2011-01-01

    A broadband dye laser pumped by a frequency-doubled Nd:YAG laser with a full-width half-maximum (FWHM) from 592 to 610 nm was created for the use in a dual-pump broadband CARS system called WIDECARS. The desired broadband dye laser was generated with a mixture of Pyrromethene dyes as an oscillator gain medium and a spectral selective optic in the oscillator cavity. A mixture of Rhodamine dyes were used in the amplifier dye cell. To create this laser a study was performed to characterize the spectral behavior of broadband dye lasers created with Rhodamine dyes 590, 610, and 640, Pyrromethene dyes 597 and 650 as well as mixture of these dyes.

  16. Evolution of oxygen utilization in multicellular organisms and implications for cell signalling in tissue engineering

    Directory of Open Access Journals (Sweden)

    Katerina Stamati

    2011-11-01

    Full Text Available Oxygen is one of the critically defining elements resulting in the existence of eukaryotic life on this planet. The rise and fall of this element can be tracked through time and corresponds with the evolution of diverse life forms, development of efficient energy production (oxidative phosphorylation in single cell organisms, the evolution of multicellular organisms and the regulation of complex cell phenotypes. By understanding these events, we can plot the effect of oxygen on evolution and its direct influence on different forms of life today, from the whole organism to specific cells within multicellular organisms. In the emerging field of tissue engineering, understanding the role of different levels of oxygen for normal cell function as well as control of complex signalling cascades is paramount to effectively build 3D tissues in vitro and their subsequent survival when implanted.

  17. AIRTV: Broadband Direct to Aircraft

    Science.gov (United States)

    Sorbello, R.; Stone, R.; Bennett, S. B.; Bertenyi, E.

    2002-01-01

    Airlines have been continuously upgrading their wide-body, long-haul aircraft with IFE (in-flight entertainment) systems that can support from 12 to 24 channels of video entertainment as well as provide the infrastructure to enable in-seat delivery of email and internet services. This is a direct consequence of increased passenger demands for improved in-flight services along with the expectations that broadband delivery systems capable of providing live entertainment (news, sports, financial information, etc.) and high speed data delivery will soon be available. The recent events of Sept. 11 have slowed the airline's upgrade of their IFE systems, but have also highlighted the compelling need for broadband aeronautical delivery systems to include operational and safety information. Despite the impact of these events, it is estimated that by 2005 more than 3000 long haul aircraft (servicing approximately 1 billion passengers annually) will be fully equipped with modern IFE systems. Current aircraft data delivery systems, which use either Inmarsat or NATS, are lacking in bandwidth and consequently are unsuitable to satisfy passenger demands for broadband email/internet services or the airlines' burgeoning data requirements. Present live video delivery services are limited to regional coverage and are not readily expandable to global or multiregional service. Faced with a compelling market demand for high data transport to aircraft, AirTV has been developing a broadband delivery system that will meet both passengers' and airlines' needs. AirTV is a global content delivery system designed to provide a range of video programming and data services to commercial airlines. When AirTV is operational in 2004, it will provide a broadband connection directly to the aircraft, delivering live video entertainment, internet/email service and essential operational and safety data. The system has been designed to provide seamless global service to all airline routes except for those

  18. AIRTV: Broadband Direct to Aircraft

    Science.gov (United States)

    Sorbello, R.; Stone, R.; Bennett, S. B.; Bertenyi, E.

    2002-01-01

    Airlines have been continuously upgrading their wide-body, long-haul aircraft with IFE (in-flight entertainment) systems that can support from 12 to 24 channels of video entertainment as well as provide the infrastructure to enable in-seat delivery of email and internet services. This is a direct consequence of increased passenger demands for improved in-flight services along with the expectations that broadband delivery systems capable of providing live entertainment (news, sports, financial information, etc.) and high speed data delivery will soon be available. The recent events of Sept. 11 have slowed the airline's upgrade of their IFE systems, but have also highlighted the compelling need for broadband aeronautical delivery systems to include operational and safety information. Despite the impact of these events, it is estimated that by 2005 more than 3000 long haul aircraft (servicing approximately 1 billion passengers annually) will be fully equipped with modern IFE systems. Current aircraft data delivery systems, which use either Inmarsat or NATS, are lacking in bandwidth and consequently are unsuitable to satisfy passenger demands for broadband email/internet services or the airlines' burgeoning data requirements. Present live video delivery services are limited to regional coverage and are not readily expandable to global or multiregional service. Faced with a compelling market demand for high data transport to aircraft, AirTV has been developing a broadband delivery system that will meet both passengers' and airlines' needs. AirTV is a global content delivery system designed to provide a range of video programming and data services to commercial airlines. When AirTV is operational in 2004, it will provide a broadband connection directly to the aircraft, delivering live video entertainment, internet/email service and essential operational and safety data. The system has been designed to provide seamless global service to all airline routes except for those

  19. Fibronectin-Alginate microcapsules improve cell viability and protein secretion of encapsulated Factor IX-engineered human mesenchymal stromal cells.

    Science.gov (United States)

    Sayyar, Bahareh; Dodd, Megan; Marquez-Curtis, Leah; Janowska-Wieczorek, Anna; Hortelano, Gonzalo

    2015-01-01

    Continuous delivery of proteins by engineered cells encapsu-lated in biocompatible polymeric microcapsules is of considerable therapeutic potential. However, this technology has not lived up to expectations due to inadequate cell--matrix interactions and subsequent cell death. In this study we hypoth-esize that the presence of fibronectin in an alginate matrix may enhance the viability and functionality of encapsulated human cord blood-derived mesenchymal stromal cells (MSCs) expressing the human Factor IX (FIX) gene. MSCs were encapsulated in alginate-PLL microcapsules containing 10, 100, or 500 μg/ml fibronectin to ameliorate cell survival. MSCs in microcapsules with 100 and 500 μg/ml fibronectin demonstrated improved cell viability and proliferation and higher FIX secretion compared to MSCs in non-supplemented microcapsules. In contrast, 10 μg/ml fibronectin did not significantly affect the viability and protein secretion from the encapsulated cells. Differentiation studies demonstrated osteogenic (but not chondrogenic or adipogenic) differentiation capability and efficient FIX secretion of the enclosed MSCs in the fibronectin-alginate suspension culture. Thus, the use of recombinant MSCs encapsulated in fibronectin-alginate microcapsules in basal or osteogenic cultures may be of practical use in the treatment of hemophilia B. PMID:24564349

  20. Fuel cells science and engineering. Materials, processes, systems and technology. Vol. 1

    Energy Technology Data Exchange (ETDEWEB)

    Stolten, Detlef; Emonts, Bernd (eds.) [Forschungszentrum Juelich GmbH (DE). Inst. fuer Energieforschung (IEF), Brennstoffzellen (IEF-3)

    2012-07-01

    -Temperature Fuel Cells (Juergen Wackerl); 20: Degradation Caused by Dynamic Operation and Starvation Conditions (Jan Hendrik Ohs, Ulrich S. Sauter and Sebastian Maass). PART IV: Quality Assurance. Chapter 21: Quality Assurance for Characterizing Low-Temperature Fuel Cells (Viktor Hacker, Eva Wallnoefer-Ogris, Georgios Tsotridis and Thomas Malkow); 22: Methodologies for Fuel Cell Process Engineering (Remzi Can Samsun and Ralf Peters).

  1. High-throughput transfection and engineering of primary cells and cultured cell lines - an invaluable tool for research as well as drug development.

    Science.gov (United States)

    Müller-Hartmann, Herbert; Faust, Nicole; Kazinski, Michael; Kretzschmar, Titus

    2007-11-01

    The manipulation of eukaryotic cells by introducing nucleic acids and other substrates using chemical, physical or viral methods is one of the ground-breaking tools in the life sciences. Changes in the molecular equipment of a cell induced by introducing different molecules not only enable the dissection of signal transduction and metabolic pathways, but also allow the exploitation of engineered cells as bio-factories for the production of proteins in the processes of target research and drug development. In addition to the application of engineered cells for modern cell-based assays, medically relevant engineered cells can be used in clinical settings for adoptive immunotherapy or gene therapy. With the advent of methods exploiting RNA interference (RNAi), gene identification and functional validation in eukaryotic cells have clearly become one of the most exciting methods in life sciences during the past few years. To accelerate research and development in these areas, high-quality, high-throughput approaches (i.e., using sample formats of at least 96 wells) for cell engineering are needed with increasing demand. Recent developments, especially in the field of electroporation, now allow the efficient, high-throughput engineering of virtually any cell type, including primary cells, many of which were previously considered difficult or even impossible to transfect. Primary cells freshly isolated from native tissues are gaining more and more interest, as data obtained with these cells are considered to be of higher physiological relevance than data obtained with immortalized cell lines that have been cultured for extensive periods. In this review, the various methods for cell engineering (with focus on higher eukaryotic cells) are summarized and their impact for high-throughput applications in research and drug development is discussed. PMID:23484597

  2. A Porous Tissue Engineering Scaffold Selectively Degraded by Cell-Generated Reactive Oxygen Species

    Science.gov (United States)

    Martin, John R.; Gupta, Mukesh K.; Page, Jonathan M.; Yu, Fang; Davidson, Jeffrey M.; Guelcher, Scott A.

    2014-01-01

    Biodegradable tissue engineering scaffolds are commonly fabricated from poly(lactide-co-glycolide) (PLGA) or similar polyesters that degrade by hydrolysis. PLGA hydrolysis generates acidic breakdown products that trigger an accelerated, autocatalytic degradation mechanism that can create mismatched rates of biomaterial breakdown and tissue formation. Reactive oxygen species (ROS) are key mediators of cell function in both health and disease, especially at sites of inflammation and tissue healing, and induction of inflammation and ROS are natural components of the in vivo response to biomaterial implantation. Thus, polymeric biomaterials that are selectively degraded by cell-generated ROS may have potential for creating tissue engineering scaffolds with better matched rates of tissue in-growth and cell-mediated scaffold biodegradation. To explore this approach, a series of poly(thioketal) (PTK) urethane (PTK-UR) biomaterial scaffolds were synthesized that degrade specifically by an ROS-dependent mechanism. PTK-UR scaffolds had significantly higher compressive moduli than analogous poly(ester urethane) (PEUR) scaffolds formed from hydrolytically-degradable ester-based diols (p < 0.05). Unlike PEUR scaffolds, the PTK-UR scaffolds were stable under aqueous conditions out to 25 weeks but were selectively degraded by ROS, indicating that their biodegradation would be exclusively cell-mediated. The in vitro oxidative degradation rates of the PTK-URs followed first-order degradation kinetics, were significantly dependent on PTK composition (p < 0.05), and correlated to ROS concentration. In subcutaneous rat wounds, PTK-UR scaffolds supported cellular infiltration and granulation tissue formation, followed first-order degradation kinetics over 7 weeks, and produced significantly greater stenting of subcutaneous wounds compared to PEUR scaffolds. These combined results indicate that ROS-degradable PTK-UR tissue engineering scaffolds have significant advantages over analogous

  3. Recent Advances in Interface Engineering for Planar Heterojunction Perovskite Solar Cells

    Directory of Open Access Journals (Sweden)

    Wei Yin

    2016-06-01

    Full Text Available Organic-inorganic hybrid perovskite solar cells are considered as one of the most promising next-generation solar cells due to their advantages of low-cost precursors, high power conversion efficiency (PCE and easy of processing. In the past few years, the PCEs have climbed from a few to over 20% for perovskite solar cells. Recent developments demonstrate that perovskite exhibits ambipolar semiconducting characteristics, which allows for the construction of planar heterojunction (PHJ perovskite solar cells. PHJ perovskite solar cells can avoid the use of high-temperature sintered mesoporous metal oxides, enabling simple processing and the fabrication of flexible and tandem perovskite solar cells. In planar heterojunction materials, hole/electron transport layers are introduced between a perovskite film and the anode/cathode. The hole and electron transporting layers are expected to enhance exciton separation, charge transportation and collection. Further, the supporting layer for the perovskite film not only plays an important role in energy-level alignment, but also affects perovskite film morphology, which have a great effect on device performance. In addition, interfacial layers also affect device stability. In this review, recent progress in interfacial engineering for PHJ perovskite solar cells will be reviewed, especially with the molecular interfacial materials. The supporting interfacial layers for the optimization of perovskite films will be systematically reviewed. Finally, the challenges remaining in perovskite solar cells research will be discussed.

  4. Recent Advances in Interface Engineering for Planar Heterojunction Perovskite Solar Cells.

    Science.gov (United States)

    Yin, Wei; Pan, Lijia; Yang, Tingbin; Liang, Yongye

    2016-01-01

    Organic-inorganic hybrid perovskite solar cells are considered as one of the most promising next-generation solar cells due to their advantages of low-cost precursors, high power conversion efficiency (PCE) and easy of processing. In the past few years, the PCEs have climbed from a few to over 20% for perovskite solar cells. Recent developments demonstrate that perovskite exhibits ambipolar semiconducting characteristics, which allows for the construction of planar heterojunction (PHJ) perovskite solar cells. PHJ perovskite solar cells can avoid the use of high-temperature sintered mesoporous metal oxides, enabling simple processing and the fabrication of flexible and tandem perovskite solar cells. In planar heterojunction materials, hole/electron transport layers are introduced between a perovskite film and the anode/cathode. The hole and electron transporting layers are expected to enhance exciton separation, charge transportation and collection. Further, the supporting layer for the perovskite film not only plays an important role in energy-level alignment, but also affects perovskite film morphology, which have a great effect on device performance. In addition, interfacial layers also affect device stability. In this review, recent progress in interfacial engineering for PHJ perovskite solar cells will be reviewed, especially with the molecular interfacial materials. The supporting interfacial layers for the optimization of perovskite films will be systematically reviewed. Finally, the challenges remaining in perovskite solar cells research will be discussed. PMID:27347923

  5. Engineered Microenvironments for the Maturation and Observation of Human Embryonic Stem Cell Derived Cardiomyocytes

    Science.gov (United States)

    Salick, Max R.

    The human heart is a dynamic system that undergoes substantial changes as it develops and adapts to the body's growing needs. To better understand the physiology of the heart, researchers have begun to produce immature heart muscle cells, or cardiomyocytes, from pluripotent stem cell sources with remarkable efficiency. These stem cell-derived cardiomyocytes hold great potential in the understanding and treatment of heart disease; however, even after prolonged culture, these cells continue to exhibit an immature phenotype, as indicated by poor sarcomere organization and calcium handling, among other features. The lack of maturation that is observed in these cardiomyocytes greatly limits their applicability towards drug screening, disease modeling, and cell therapy applications. The mechanical environment surrounding a cell has been repeatedly shown to have a large impact on that cell's behavior. For this reason, we have implemented micropatterning methods to mimic the level of alignment that occurs in the heart in vivo in order to study how this alignment may help the cells to produce a more mature sarcomere phenotype. It was discovered that the level of sarcomere organization of a cardiomyocyte can be strongly influenced by the micropattern lane geometry on which it adheres. Steps were taken to optimize this micropattern platform, and studies of protein organization, gene expression, and myofibrillogenesis were conducted. Additionally, a set of programs was developed to provide quantitative analysis of the level of sarcomere organization, as well as to assist with several other tissue engineering applications.

  6. Advantages of Sheep Infrapatellar Fat Pad Adipose Tissue Derived Stem Cells in Tissue Engineering

    Science.gov (United States)

    Vahedi, Parviz; Soleimanirad, Jafar; Roshangar, Leila; Shafaei, Hajar; Jarolmasjed, Seyedhosein; Nozad Charoudeh, Hojjatollah

    2016-01-01

    Purpose: The goal of this study has been to evaluate adipose tissue derived stem cells (ADSCs) from infrapatellar fat pad and characterize their cell surface markers using anti-human antibodies, as adipose tissue derived stem cells (ADSCs) have great potential for cellular therapies to restore injured tissues. Methods: Adipose tissue was obtained from infrapatellar fat pad of sheep. Surface markers evaluated by flow cytometry. In order to evaluate cell adhesion, the Polycaprolactone (PCL) was sterilized under Ultraviolet (UV) light and about 1×105 cells were seeded on PCL. Then, ASCs- PCL construct were evaluated by Scanning Electron Microscopy (Mira3 Te Scan, Czech Republic). Results: We showed that adipose tissue derived stem cells (ADSCs) maintain their fibroblastic-like morphology during different subcultures and cell adhesion. They were positive for CD44 and CD90 markers and negative for CD31 and Cd45 markers by human antibodies. Conclusion: Our results suggest that ASCs surface markers can be characterized by anti-human antibodies in sheep. As stem cells, they can be used in tissue engineering. PMID:27123425

  7. Human amniotic fluid derived cells can competently substitute dermal fibroblasts in a tissue-engineered dermo-epidermal skin analog

    NARCIS (Netherlands)

    Hartmann-Fritsch, Fabienne; Hosper, Nynke; Luginbuehl, Joachim; Biedermann, Thomas; Reichmann, Ernst; Meuli, Martin

    2013-01-01

    Human amniotic fluid comprises cells with high differentiation capacity, thus representing a potential cell source for skin tissue engineering. In this experimental study, we investigated the ability of human amniotic fluid derived cells to substitute dermal fibroblasts and support epidermis formati

  8. A special issue on reviews in biomedical applications of nanomaterials, tissue engineering, stem cells, bioimaging, and toxicity.

    Science.gov (United States)

    Nalwa, Hari Singh

    2014-10-01

    This second special issue of the Journal of Biomedical Nanotechnology in a series contains another 30 state-of-the-art reviews focused on the biomedical applications of nanomaterials, biosensors, bone tissue engineering, MRI and bioimaging, single-cell detection, stem cells, endothelial progenitor cells, toxicity and biosafety of nanodrugs, nanoparticle-based new therapeutic approaches for cancer, hepatic and cardiovascular disease. PMID:25992404

  9. High-resolution Precipitation and Lightning Monitoring by the Ku-band Broadband Radar and the VHF Broadband Digital Interferometer

    Science.gov (United States)

    Nakamura, Yoshitaka; Yoshikawa, Eiichi; Akita, Manabu; Morimoto, Takeshi; Ushio, Tomoo; Kawasaki, Zen-Ichiro; Saito, Toshiya; Nishida, Takashi; Sakazume, Norio

    We propose a high-resolution precipitation and lightning monitoring for meteorological application. This monitoring is mainly utilized the Ku-band broadband radar (BBR) and the VHF broadband digital interferometer (DITF). The BBR can accurately measure the radar reflectivity factor and the mean Doppler velocity with 5 m resolution over a range from 40 m to several kilometers for 10 W power using a pulse compression technique. The two or more DITFs make us visualize lightning channel propagations in three dimensions. Moreover, we add new functions that integrate these observation data and disclose integration analyses results with the quasi real-time information disclosure system. Initial observations for severe storms with lightning during summer and winter thunderstorm season by these monitoring instruments indicate that we obtain detailed precipitation distribution and detect active convective cells with lightning discharges.

  10. A validated system for ligation-free USER™ -based assembly of expression vectors for mammalian cell engineering

    DEFF Research Database (Denmark)

    Lund, Anne Mathilde; Kildegaard, Helene Faustrup; Hansen, Bjarne Gram; Holm, Dorte Koefoed; Andersen, Mikael Rørdam; Mortensen, Uffe Hasbro

    The development in the field of mammalian cell factories require fast and high-throughput methods, this means a high need for simpler and more efficient cloning techniques. For optimization of protein expression by genetic engineering and for allowing metabolic engineering in mammalian cells, a n...... versatile expression vector system was developed. This vector system applies the ligation-free uracilexcision cloning technique to construct mammalian expression vectors of multiple parts and with maximum flexibility.......The development in the field of mammalian cell factories require fast and high-throughput methods, this means a high need for simpler and more efficient cloning techniques. For optimization of protein expression by genetic engineering and for allowing metabolic engineering in mammalian cells, a new...

  11. Biocompatible Azide-Alkyne "Click" Reactions for Surface Decoration of Glyco-Engineered Cells.

    Science.gov (United States)

    Gutmann, Marcus; Memmel, Elisabeth; Braun, Alexandra C; Seibel, Jürgen; Meinel, Lorenz; Lühmann, Tessa

    2016-05-01

    Bio-orthogonal copper (I)-catalyzed azide-alkyne cycloaddition (CuAAC) has been widely used to modify azide- or alkyne-bearing monosaccharides on metabolic glyco-engineered mammalian cells. Here, we present a systematic study to elucidate the design space for the cytotoxic effects of the copper catalyst on NIH 3T3 fibroblasts and on HEK 293-F cells. Monitoring membrane integrity by flow cytometry and RT-PCR analysis with apoptotic and anti-apoptotic markers elucidated the general feasibility of CuAAC, with exposure time of the CuAAC reaction mixture having the major influence on biocompatibility. A high labeling efficiency of HEK 293-F cells with a fluorescent alkyne dye was rapidly achieved by CuAAC in comparison to copper free strain-promoted azide-alkyne cycloaddition (SPAAC). The study details effective and biocompatible conditions for CuAAC-based modification of glyco-engineered cells in comparison to its copper free alternative. PMID:26818821

  12. Spatial Engineering of Osteochondral Tissue Constructs Through Microfluidically Directed Differentiation of Mesenchymal Stem Cells

    Science.gov (United States)

    Goldman, Stephen M.; Barabino, Gilda A.

    2016-01-01

    Abstract The development of tissue engineered osteochondral units has been slowed by a number of technical hurdles associated with recapitulating their heterogeneous nature ex vivo. Subsequently, numerous approaches with respect to cell sourcing, scaffolding composition, and culture media formulation have been pursued, which have led to high variability in outcomes and ultimately the lack of a consensus bioprocessing strategy. As such, the objective of this study was to standardize the design process by focusing on differentially supporting formation of cartilaginous and bony matrix by a single cell source in a spatially controlled manner within a single material system. A cell-polymer solution of bovine mesenchymal stem cells and agarose was cast against micromolds of a serpentine network and stacked to produce tissue constructs containing two independent microfluidic networks. Constructs were fluidically connected to two controlled flow loops and supplied with independently tuned differentiation parameters for chondrogenic and osteogenic induction, respectively. Constructs receiving inductive media showed differential gene expression of both chondrogenic and osteogenic markers in opposite directions along the thickness of the construct that was recapitulated at the protein level with respect to collagens I, II, and X. A control group receiving noninductive media showed homogeneous expression of these biomarkers measured in lower concentrations at both the mRNA and protein level. This work represents an important step in the rational design of engineered osteochondral units through establishment of an enabling technology for further optimization of scaffolding formulations and bioprocessing conditions toward the production of commercially viable osteochondral tissue products.

  13. Suicide Gene-Engineered Stromal Cells Reveal a Dynamic Regulation of Cancer Metastasis

    Science.gov (United States)

    Shen, Keyue; Luk, Samantha; Elman, Jessica; Murray, Ryan; Mukundan, Shilpaa; Parekkadan, Biju

    2016-02-01

    Cancer-associated fibroblasts (CAFs) are a major cancer-promoting component in the tumor microenvironment (TME). The dynamic role of human CAFs in cancer progression has been ill-defined because human CAFs lack a unique marker needed for a cell-specific, promoter-driven knockout model. Here, we developed an engineered human CAF cell line with an inducible suicide gene to enable selective in vivo elimination of human CAFs at different stages of xenograft tumor development, effectively circumventing the challenge of targeting a cell-specific marker. Suicide-engineered CAFs were highly sensitive to apoptosis induction in vitro and in vivo by the addition of a simple small molecule inducer. Selection of timepoints for targeted CAF apoptosis in vivo during the progression of a human breast cancer xenograft model was guided by a bi-phasic host cytokine response that peaked at early timepoints after tumor implantation. Remarkably, we observed that the selective apoptosis of CAFs at these early timepoints did not affect primary tumor growth, but instead increased the presence of tumor-associated macrophages and the metastatic spread of breast cancer cells to the lung and bone. The study revealed a dynamic relationship between CAFs and cancer metastasis that has counter-intuitive ramifications for CAF-targeted therapy.

  14. Spatial Engineering of Osteochondral Tissue Constructs Through Microfluidically Directed Differentiation of Mesenchymal Stem Cells.

    Science.gov (United States)

    Goldman, Stephen M; Barabino, Gilda A

    2016-01-01

    The development of tissue engineered osteochondral units has been slowed by a number of technical hurdles associated with recapitulating their heterogeneous nature ex vivo. Subsequently, numerous approaches with respect to cell sourcing, scaffolding composition, and culture media formulation have been pursued, which have led to high variability in outcomes and ultimately the lack of a consensus bioprocessing strategy. As such, the objective of this study was to standardize the design process by focusing on differentially supporting formation of cartilaginous and bony matrix by a single cell source in a spatially controlled manner within a single material system. A cell-polymer solution of bovine mesenchymal stem cells and agarose was cast against micromolds of a serpentine network and stacked to produce tissue constructs containing two independent microfluidic networks. Constructs were fluidically connected to two controlled flow loops and supplied with independently tuned differentiation parameters for chondrogenic and osteogenic induction, respectively. Constructs receiving inductive media showed differential gene expression of both chondrogenic and osteogenic markers in opposite directions along the thickness of the construct that was recapitulated at the protein level with respect to collagens I, II, and X. A control group receiving noninductive media showed homogeneous expression of these biomarkers measured in lower concentrations at both the mRNA and protein level. This work represents an important step in the rational design of engineered osteochondral units through establishment of an enabling technology for further optimization of scaffolding formulations and bioprocessing conditions toward the production of commercially viable osteochondral tissue products. PMID:27190700

  15. Development of large engineered cartilage constructs from a small population of cells.

    Science.gov (United States)

    Brenner, Jillian M; Kunz, Manuela; Tse, Man Yat; Winterborn, Andrew; Bardana, Davide D; Pang, Stephen C; Waldman, Stephen D

    2013-01-01

    Confronted with articular cartilage's limited capacity for self-repair, joint resurfacing techniques offer an attractive treatment for damaged or diseased tissue. Although tissue engineered cartilage constructs can be created, a substantial number of cells are required to generate sufficient quantities of tissue for the repair of large defects. As routine cell expansion methods tend to elicit negative effects on chondrocyte function, we have developed an approach to generate phenotypically stable, large-sized engineered constructs (≥3 cm(2) ) directly from a small amount of donor tissue or cells (as little as 20,000 cells to generate a 3 cm(2) tissue construct). Using rabbit donor tissue, the bioreactor-cultivated constructs were hyaline-like in appearance and possessed a biochemical composition similar to native articular cartilage. Longer bioreactor cultivation times resulted in increased matrix deposition and improved mechanical properties determined over a 4 week period. Additionally, as the anatomy of the joint will need to be taken in account to effectively resurface large affected areas, we have also explored the possibility of generating constructs matched to the shape and surface geometry of a defect site through the use of rapid-prototyped defect tissue culture molds. Similar hyaline-like tissue constructs were developed that also possessed a high degree of shape correlation to the original defect mold. Future studies will be aimed at determining the effectiveness of this approach to the repair of cartilage defects in an animal model and the creation of large-sized osteochondral constructs. PMID:23197468

  16. Stem cell-derived vasculature: A potent and multidimensional technology for basic research, disease modeling, and tissue engineering.

    Science.gov (United States)

    Lowenthal, Justin; Gerecht, Sharon

    2016-05-01

    Proper blood vessel networks are necessary for constructing and re-constructing tissues, promoting wound healing, and delivering metabolic necessities throughout the body. Conversely, an understanding of vascular dysfunction has provided insight into the pathogenesis and progression of diseases both common and rare. Recent advances in stem cell-based regenerative medicine - including advances in stem cell technologies and related progress in bioscaffold design and complex tissue engineering - have allowed rapid advances in the field of vascular biology, leading in turn to more advanced modeling of vascular pathophysiology and improved engineering of vascularized tissue constructs. In this review we examine recent advances in the field of stem cell-derived vasculature, providing an overview of stem cell technologies as a source for vascular cell types and then focusing on their use in three primary areas: studies of vascular development and angiogenesis, improved disease modeling, and the engineering of vascularized constructs for tissue-level modeling and cell-based therapies. PMID:26427871

  17. Engineering Cartilage

    Science.gov (United States)

    ... Research Matters NIH Research Matters March 3, 2014 Engineering Cartilage Artistic rendering of human stem cells on ... situations has been a major goal in tissue engineering. Cartilage contains water, collagen, proteoglycans, and chondrocytes. Collagens ...

  18. Cell painting with an engineered EPCR to augment the protein C system.

    Science.gov (United States)

    Bouwens, Eveline A M; Stavenuiter, Fabian; Mosnier, Laurent O

    2015-11-25

    The protein C (PC) system conveys beneficial anticoagulant and cytoprotective effects in numerous in vivo disease models. The endothelial protein C receptor (EPCR) plays a central role in these pathways as cofactor for PC activation and by enhancing activated protein C (APC)-mediated protease-activated receptor (PAR) activation. During inflammatory disease, expression of EPCR on cell membranes is often diminished thereby limiting PC activation and APC's effects on cells. Here a caveolae-targeting glycosylphosphatidylinositol (GPI)-anchored EPCR (EPCR-GPI) was engineered to restore EPCR's bioavailability via "cell painting." The painting efficiency of EPCR-GPI on EPCR-depleted endothelial cells was time- and dose-dependent. The EPCR-GPI bioavailability after painting was long lasting since EPCR surface levels reached 400 % of wild-type cells after 2 hours and remained > 200 % for 24 hours. EPCR-GPI painting conveyed APC binding to EPCR-depleted endothelial cells where EPCR was lost due to shedding or shRNA. EPCR painting normalised PC activation on EPCR-depleted cells indicating that EPCR-GPI is functional active on painted cells. Caveolin-1 lipid rafts were enriched in EPCR after painting due to the GPI-anchor targeting caveolae. Accordingly, EPCR painting supported PAR1 and PAR3 cleavage by APC and augmented PAR1-dependent Akt phosphorylation by APC. Thus, EPCR-GPI painting achieved physiological relevant surface levels on endothelial cells, restored APC binding to EPCR-depleted cells, supported PC activation, and enhanced APC-mediated PAR cleavage and cytoprotective signalling. Therefore, EPCR-GPI provides a novel tool to restore the bioavailability and functionality of EPCR on EPCR- depleted and -deficient cells. PMID:26272345

  19. Continuous release of interleukin 12 from microencapsulated engineered cells for colon cancer therapy

    Institute of Scientific and Technical Information of China (English)

    Shu Zheng; Zuo-Xiang Xiao; Yue-Long Pan; Ming-Yong Han; Qi Dong

    2003-01-01

    AIM: To explore the anti-tumor immunity against CT26 colon tumor of the microencapsulated cells modified with murine interleukine-12 (mIL-12) gene.METHODS: Mouse fibroblasts (NIH3T3) were stably transfected to express mIL-12 using expression plasmids carrying mIL-12 gene (p35 and p40), and NIH3T3-mIL-12cells were encapsulated in alginate microcapsules for longterm delivery of mIL-12. mIL-12 released from the microencapsulated NIH3T3-mIL-12 cells was confirmed using ELISA assay. Transplantation of the microencapsulated NIH3T3-mIL-12 cells was performed in the tumor-bearing mice with CT26 cells. The anti-tumor responses and the anti-tumor activities of the microencapsulated NIH3T3-mIL12 cells were evaluated.RESULTS: Microencapsulated NIH3T3-mIL-12 cells could release mIL-12 continuously and stably for a long time. After the microencapsulated NIH3T3-mIL-12 cells were transplanted subcutaneously into the tumor-bearing mice for 21 d, the serum concentrations of mIL-12, mIL-2 and mIFN-γ the cytotoxicity of the CTL from the splenocytes and the NK activity in the treatment group were significantly higher than those in the controls. Moreover, mIL-12 released from the microencapsulated NIH3T3-mIL-12 cells resulted in a significant inhibition of tumor proliferation and a prolonged survival of tumor-bearing mice.CONCLUSION: The microencapsulated NIH3T3-mIL-12cells have a significant therapeutic effect on the experimental colon tumor by activating anti-tumor immune responses in vivo. Microencapsulated and genetically engineered cells may be an extremely versatile tool for tumor gene therapy.

  20. Development of Multifunctional Magnetic Nanoparticles for Genetic Engineering and Tracking of Neural Stem Cells.

    Science.gov (United States)

    Adams, Christopher; Israel, Liron Limor; Ostrovsky, Stella; Taylor, Arthur; Poptani, Harish; Lellouche, Jean-Paul; Chari, Divya

    2016-04-01

    Genetic modification of cell transplant populations and cell tracking ability are key underpinnings for effective cell therapies. Current strategies to achieve these goals utilize methods which are unsuitable for clinical translation because of related safety issues, and multiple protocol steps adding to cost and complexity. Multifunctional magnetic nanoparticles (MNPs) offering dual mode gene delivery and imaging contrast capacity offer a valuable tool in this context. Despite their key benefits, there is a critical lack of neurocompatible and multifunctional particles described for use with transplant populations for neurological applications. Here, a systematic screen of MNPs (using a core shown to cause contrast in magnetic resonance imaging (MRI)) bearing various surface chemistries (polyethylenimine (PEI) and oxidized PEI and hybrids of oxidized PEI/alginic acid, PEI/chitosan and PEI/polyamidoamine) is performed to test their ability to genetically engineer neural stem cells (NSCs; a cell population of high clinical relevance for central nervous system disorders). It is demonstrated that gene delivery to NSCs can be safely achieved using two of the developed formulations (PEI and oxPEI/alginic acid) when used in conjunction with oscillating magnetofection technology. After transfection, intracellular particles can be detected by histological procedures with labeled cells displaying contrast in MRI (for real time cell tracking). PMID:26867130

  1. Temperature-responsive intelligent interfaces for biomolecular separation and cell sheet engineering.

    Science.gov (United States)

    Nagase, Kenichi; Kobayashi, Jun; Okano, Teruo

    2009-06-01

    Temperature-responsive intelligent surfaces, prepared by the modification of an interface with poly(N-isopropylacrylamide) and its derivatives, have been used for biomedical applications. Such surfaces exhibit temperature-responsive hydrophilic/hydrophobic alterations with external temperature changes, which, in turn, result in thermally modulated interactions with biomolecules and cells. In this review, we focus on the application of these intelligent surfaces to chromatographic separation and cell cultures. Chromatographic separations using several types of intelligent surfaces are mentioned briefly, and various effects related to the separation of bioactive compounds are discussed, including wettability, copolymer composition and graft polymer architecture. Similarly, we also summarize temperature-responsive cell culture substrates that allow the recovery of confluent cell monolayers as contiguous living cell sheets for tissue-engineering applications. The key factors in temperature-dependent cell adhesion/detachment control are discussed from the viewpoint of grafting temperature-responsive polymers, and new methodologies for effective cell sheet culturing and the construction of thick tissues are summarized. PMID:19324682

  2. A validated system for ligation-free USER™ -based assembly of expression vectors for mammalian cell engineering

    OpenAIRE

    Lund, Anne Mathilde; Kildegaard, Helene Faustrup; Hansen, Bjarne Gram; Holm, Dorte Koefoed; Andersen, Mikael Rørdam; Mortensen, Uffe Hasbro

    2013-01-01

    The development in the field of mammalian cell factories require fast and high-throughput methods, this means a high need for simpler and more efficient cloning techniques. For optimization of protein expression by genetic engineering and for allowing metabolic engineering in mammalian cells, a new versatile expression vector system was developed. This vector system applies the ligation-free uracilexcision cloning technique to construct mammalian expression vectors of multiple parts and with ...

  3. Functional stability of endothelial cells on a novel hybrid scaffold for vascular tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Pankajakshan, Divya; Krishnan, Lissy K [Thrombosis Research Unit, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Poojapura, Trivandrum 695 012 (India); Krishnan V, Kalliyana, E-mail: lissykk@sctimst.ac.i [Division of Polymer Technology, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Poojapura, Trivandrum 695 012 (India)

    2010-12-15

    Porous and pliable conduits made of biodegradable polymeric scaffolds offer great potential for the development of blood vessel substitutes but they generally lack signals for cell proliferation, survival and maintenance of a normal phenotype. In this study we have prepared and evaluated porous poly({epsilon}-caprolactone) (PCL) integrated with fibrin composite (FC) to get a biomimetic hybrid scaffold (FC PCL) with the biological properties of fibrin, fibronectin (FN), gelatin, growth factors and glycosaminoglycans. Reduced platelet adhesion on a human umbilical vein endothelial cell-seeded hybrid scaffold as compared to bare PCL or FC PCL was observed, which suggests the non-thrombogenic nature of the tissue-engineered scaffold. Analysis of real-time polymerase chain reaction (RT-PCR) after 5 days of endothelial cell (EC) culture on a hybrid scaffold indicated that the prothrombotic von Willebrand factor and plasminogen activator inhibitor (PAI) were quiescent and stable. Meanwhile, dynamic expressions of tissue plasminogen activator (tPA) and endothelial nitric oxide synthase indicated the desired cell phenotype on the scaffold. On the hybrid scaffold, shear stress could induce enhanced nitric oxide release, which implicates vaso-responsiveness of EC grown on the tissue-engineered construct. Significant upregulation of mRNA for extracellular matrix (ECM) proteins, collagen IV and elastin, in EC was detected by RT-PCR after growing them on the hybrid scaffold and FC-coated tissue culture polystyrene (FC TCPS) but not on FN-coated TCPS. The results indicate that the FC PCL hybrid scaffold can accomplish a remodeled ECM and non-thrombogenic EC phenotype, and can be further investigated as a scaffold for cardiovascular tissue engineering. (communication)

  4. Functional stability of endothelial cells on a novel hybrid scaffold for vascular tissue engineering

    International Nuclear Information System (INIS)

    Porous and pliable conduits made of biodegradable polymeric scaffolds offer great potential for the development of blood vessel substitutes but they generally lack signals for cell proliferation, survival and maintenance of a normal phenotype. In this study we have prepared and evaluated porous poly(ε-caprolactone) (PCL) integrated with fibrin composite (FC) to get a biomimetic hybrid scaffold (FC PCL) with the biological properties of fibrin, fibronectin (FN), gelatin, growth factors and glycosaminoglycans. Reduced platelet adhesion on a human umbilical vein endothelial cell-seeded hybrid scaffold as compared to bare PCL or FC PCL was observed, which suggests the non-thrombogenic nature of the tissue-engineered scaffold. Analysis of real-time polymerase chain reaction (RT-PCR) after 5 days of endothelial cell (EC) culture on a hybrid scaffold indicated that the prothrombotic von Willebrand factor and plasminogen activator inhibitor (PAI) were quiescent and stable. Meanwhile, dynamic expressions of tissue plasminogen activator (tPA) and endothelial nitric oxide synthase indicated the desired cell phenotype on the scaffold. On the hybrid scaffold, shear stress could induce enhanced nitric oxide release, which implicates vaso-responsiveness of EC grown on the tissue-engineered construct. Significant upregulation of mRNA for extracellular matrix (ECM) proteins, collagen IV and elastin, in EC was detected by RT-PCR after growing them on the hybrid scaffold and FC-coated tissue culture polystyrene (FC TCPS) but not on FN-coated TCPS. The results indicate that the FC PCL hybrid scaffold can accomplish a remodeled ECM and non-thrombogenic EC phenotype, and can be further investigated as a scaffold for cardiovascular tissue engineering. (communication)

  5. Muscle Tissue Engineering Using Gingival Mesenchymal Stem Cells Encapsulated in Alginate Hydrogels Containing Multiple Growth Factors.

    Science.gov (United States)

    Ansari, Sahar; Chen, Chider; Xu, Xingtian; Annabi, Nasim; Zadeh, Homayoun H; Wu, Benjamin M; Khademhosseini, Ali; Shi, Songtao; Moshaverinia, Alireza

    2016-06-01

    Repair and regeneration of muscle tissue following traumatic injuries or muscle diseases often presents a challenging clinical situation. If a significant amount of tissue is lost the native regenerative potential of skeletal muscle will not be able to grow to fill the defect site completely. Dental-derived mesenchymal stem cells (MSCs) in combination with appropriate scaffold material, present an advantageous alternative therapeutic option for muscle tissue engineering in comparison to current treatment modalities available. To date, there has been no report on application of gingival mesenchymal stem cells (GMSCs) in three-dimensional scaffolds for muscle tissue engineering. The objectives of the current study were to develop an injectable 3D RGD-coupled alginate scaffold with multiple growth factor delivery capacity for encapsulating GMSCs, and to evaluate the capacity of encapsulated GMSCs to differentiate into myogenic tissue in vitro and in vivo where encapsulated GMSCs were transplanted subcutaneously into immunocompromised mice. The results demonstrate that after 4 weeks of differentiation in vitro, GMSCs as well as the positive control human bone marrow mesenchymal stem cells (hBMMSCs) exhibited muscle cell-like morphology with high levels of mRNA expression for gene markers related to muscle regeneration (MyoD, Myf5, and MyoG) via qPCR measurement. Our quantitative PCR analyzes revealed that the stiffness of the RGD-coupled alginate regulates the myogenic differentiation of encapsulated GMSCs. Histological and immunohistochemical/fluorescence staining for protein markers specific for myogenic tissue confirmed muscle regeneration in subcutaneous transplantation in our in vivo animal model. GMSCs showed significantly greater capacity for myogenic regeneration in comparison to hBMMSCs (p < 0.05). Altogether, our findings confirmed that GMSCs encapsulated in RGD-modified alginate hydrogel with multiple growth factor delivery capacity is a promising

  6. The impact of broadband in schools: Summary report

    OpenAIRE

    Underwood, Jean; Ault, Alison; Banyard, Phil; Bird, Karen; Dillon, Gayle; Hayes, Mary; Selwood, Ian; Somekh, Bridget; Twining, Peter

    2005-01-01

    Summary of the report, which reviews evidence for the impact of broadband in English schools, exploring; variations in provision in level of broadband connectivity. Links between the level of broadband activity and nationally accessible performance data; aspects of broadband connectivity and the school environment that contribute to better outcomes for pupils and teachers; academic and motivational benefits associated with educational uses of this technology.

  7. 47 CFR 27.1305 - Shared wireless broadband network.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Shared wireless broadband network. 27.1305... broadband network. The Shared Wireless Broadband Network developed by the 700 MHz Public/Private Partnership must be designed to meet requirements associated with a nationwide, public safety broadband network....

  8. 47 CFR 90.1405 - Shared wireless broadband network.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Shared wireless broadband network. 90.1405... broadband network. The Shared Wireless Broadband Network developed by the 700 MHz Public/Private Partnership must be designed to meet requirements associated with a nationwide, public safety broadband network....

  9. Differentiation of mesenchymal stem cells into neuronal cells on fetal bovine acellular dermal matrix as a tissue engineered nerve scaffold

    Institute of Scientific and Technical Information of China (English)

    Yuping Feng; Jiao Wang; Shixin Ling; Zhuo Li; Mingsheng Li; Qiongyi Li; Zongren Ma; Sijiu Yu

    2014-01-01

    The purpose of this study was to assess fetal bovine acellular dermal matrix as a scaffold for supporting the differentiation of bone marrow mesenchymal stem cells into neural cells fol-lowing induction with neural differentiation medium. We performed long-term, continuous observation of cell morphology, growth, differentiation, and neuronal development using several microscopy techniques in conjunction with immunohistochemistry. We examined speciifc neu-ronal proteins and Nissl bodies involved in the differentiation process in order to determine the neuronal differentiation of bone marrow mesenchymal stem cells. The results show that bone marrow mesenchymal stem cells that differentiate on fetal bovine acellular dermal matrix display neuronal morphology with unipolar and bi/multipolar neurite elongations that express neuro-nal-speciifc proteins, includingβIII tubulin. The bone marrow mesenchymal stem cells grown on fetal bovine acellular dermal matrix and induced for long periods of time with neural differen-tiation medium differentiated into a multilayered neural network-like structure with long nerve ifbers that was composed of several parallel microifbers and neuronal cells, forming a complete neural circuit with dendrite-dendrite to axon-dendrite to dendrite-axon synapses. In addition, growth cones with filopodia were observed using scanning electron microscopy. Paraffin sec-tioning showed differentiated bone marrow mesenchymal stem cells with the typical features of neuronal phenotype, such as a large, round nucleus and a cytoplasm full of Nissl bodies. The data suggest that the biological scaffold fetal bovine acellular dermal matrix is capable of supporting human bone marrow mesenchymal stem cell differentiation into functional neurons and the subsequent formation of tissue engineered nerve.

  10. Towards Engineered Processes for Sequencing-Based Analysis of Single Circulating Tumor Cells.

    Science.gov (United States)

    Adalsteinsson, Viktor A; Love, J Christopher

    2014-05-01

    Sequencing-based analysis of single circulating tumor cells (CTCs) has the potential to revolutionize our understanding of metastatic cancer and improve clinical care. Technologies exist to enrich, identify, recover, and sequence single cells, but to enable systematic routine analysis of single CTCs from a range of cancer patients, there is a need to establish processes that efficiently integrate these specific operations. Such engineered processes should address challenges associated with the yield and viability of enriched CTCs, the robust identification of candidate single CTCs with minimal degradation of DNA, the bias in whole-genome amplification, and the efficient handling of candidate single CTCs or their amplified DNA products. Advances in methods for single-cell analysis and nanoscale technologies suggest opportunities to overcome these challenges, and could create integrated platforms that perform several of the unit operations together. Ultimately, technologies should be selected or adapted for optimal performance and compatibility in an integrated process. PMID:24839591

  11. Physiological, pathological, and engineered cell identity reprogramming in the central nervous system.

    Science.gov (United States)

    Smith, Derek K; Wang, Lei-Lei; Zhang, Chun-Li

    2016-07-01

    Multipotent neural stem cells persist in restricted regions of the adult mammalian central nervous system. These proliferative cells differentiate into diverse neuron subtypes to maintain neural homeostasis. This endogenous process can be reprogrammed as a compensatory response to physiological cues, traumatic injury, and neurodegeneration. In addition to innate neurogenesis, recent research has demonstrated that new neurons can be engineered via cell identity reprogramming in non-neurogenic regions of the adult central nervous system. A comprehensive understanding of these reprogramming mechanisms will be essential to the development of therapeutic neural regeneration strategies that aim to improve functional recovery after injury and neurodegeneration. WIREs Dev Biol 2016, 5:499-517. doi: 10.1002/wdev.234 For further resources related to this article, please visit the WIREs website. PMID:27258392

  12. Investigation the Porous Collagen-Chitosan /Glycosaminoglycans for Corneal Cell Culture as Tissue Engineering Scaffold

    Institute of Scientific and Technical Information of China (English)

    LI Qin-Hua; CHEN Jian-Su

    2005-01-01

    The objective of this study was to produce the porous collagen-chitosan/Glycosanminglycans (GAG) for corneal ceil-seed implant as a three-dimensional tissue engineering scaffold to improve the regeneration corneas. The effect of various content of glycerol as form porous agent to collagen-chitosan/GAG preserved a porous dimensional structure was investigated. The heat-drying was used to prepare porous collagen-chitosan /GAG scaffold. The pore morphology of collagenchitosan/GAG was controlled by changing the concentration of glycerol solution and drying methods. The porous structure morphology was observed by SEM. The diameter of the pores form 10 to 50 μm. The highly porous scaffold had interconnecting pores. The corneal cell morphology was observed under the light microscope. These results suggest that collagen-chitosan/GAG showed that corneal cell have formed confluent layers and resemble the surface of normal corneal cell surface.

  13. Three-dimensional broadband omnidirectional acoustic ground cloak.

    Science.gov (United States)

    Zigoneanu, Lucian; Popa, Bogdan-Ioan; Cummer, Steven A

    2014-04-01

    The control of sound propagation and reflection has always been the goal of engineers involved in the design of acoustic systems. A recent design approach based on coordinate transformations, which is applicable to many physical systems, together with the development of a new class of engineered materials called metamaterials, has opened the road to the unconstrained control of sound. However, the ideal material parameters prescribed by this methodology are complex and challenging to obtain experimentally, even using metamaterial design approaches. Not surprisingly, experimental demonstration of devices obtained using transformation acoustics is difficult, and has been implemented only in two-dimensional configurations. Here, we demonstrate the design and experimental characterization of an almost perfect three-dimensional, broadband, and, most importantly, omnidirectional acoustic device that renders a region of space three wavelengths in diameter invisible to sound. PMID:24608143

  14. Integrated cell and process engineering for improved transient production of a "difficult-to-express" fusion protein by CHO cells.

    Science.gov (United States)

    Johari, Yusuf B; Estes, Scott D; Alves, Christina S; Sinacore, Marty S; James, David C

    2015-12-01

    Based on an optimized electroporation protocol, we designed a rapid, milliliter-scale diagnostic transient production assay to identify limitations in the ability of Chinese hamster ovary (CHO) cells to produce a model "difficult-to-express" homodimeric Fc-fusion protein, Sp35Fc, that exhibited very low volumetric titer and intracellular formation of disulfide-bonded oligomeric aggregates post-transfection. As expression of Sp35Fc induced an unfolded protein response in transfected host cells, we utilized the transient assay to compare, in parallel, multiple functionally diverse strategies to engineer intracellular processing of Sp35Fc in order to increase production and reduce aggregation as two discrete design objectives. Specifically, we compared the effect of (i) co-expression of ER-resident molecular chaperones (BiP, PDI, CypB) or active forms of UPR transactivators (ATF6c, XBP1s) at varying recombinant gene load, (ii) addition of small molecules known to act as chemical chaperones (PBA, DMSO, glycerol, betaine, TMAO) or modulate UPR signaling (PERK inhibitor GSK2606414) at varying concentration, (iii) a reduction in culture temperature to 32°C. Using this information, we designed a biphasic, Sp35Fc-specific transient manufacturing process mediated by lipofection that utilized CypB co-expression at an optimal Sp35Fc:CypB gene ratio of 5:1 to initially maximize transfected cell proliferation, followed by addition of a combination of PBA (0.5 mM) and glycerol (1% v/v) at the onset of stationary phase to maximize cell specific production and eliminate Sp35Fc aggregation. Using this optimal, engineered process transient Sp35Fc production was significantly increased sixfold over a 12 day production process with no evidence of disulfide-bonded aggregates. Finally, transient production in clonally derived sub-populations (derived from parental CHO host) screened for a heritably improved capability to produce Sp35Fc was also significantly improved by the optimized

  15. A Cell Lysis and Protein Purification - Single Molecule Assay Devices for Evaluation of Genetically Engineered Proteins

    Science.gov (United States)

    Nakyama, Tetsuya; Tabata, Kazuhito; Noji, Hiroyuki; Yokokawa, Ryuji

    We have developed two devices applicable to evaluate genetically engineered proteins in single molecule assay: on-chip cell lysis device, and protein purification - assay device. A motor protein, F1-ATPase expressed in E.coli, was focused in this report as a target protein. Cell lysis was simply performed by applying pulse voltage between Au electrodes patterned by photolithography, and its efficiency was determined by absorptiometry. The subsequent processes, purification and assay of extracted proteins, were demonstrated in order to detect F1-ATPase and to evaluate its activity. The specific bonding between his-tag in F1-ATPase and Ni-NTA coated on a glass surface was utilized for the purification process. After immobilization of F1-ATPase, avidin-coated microspheres and adenosine tri-phosphate (ATP) solution were infused sequentially to assay the protein. Microsphere rotation was realized by activity of F1-ATPase corresponding to ATP hydrolysis. Results show that the cell lysis device, at the optimum condition, extracts enough amount of protein for single molecule assay. Once cell lysate was injected to the purification - assay device, proteins were diffused in the lateral direction in a Y-shape microchannel. The gradient of protein concentratioin provides an optimal concentration for the assay i.e. the highest density of rotating beads. Density of rotating beads is also affected by the initial concentration of protein injected to the device. The optimum concentration was achieved by our cell lysis device not by the conventional method by ultrasonic wave. Rotation speed was analyzed for several microspheres assayed in the purification - assay device, and the results were compatible to that of conventional assay in which F1-ATPase was purified in bulk scale. In conclusion, we have demonstrated on-chip cell lysis and assay appropriate for the sequential analysis without any pretreatment. On-chip devices replacing conventional bioanalytical methods will be

  16. Broadband Adoption And Use In America

    Data.gov (United States)

    Federal Communications Commission — On February 23, 2010, the FCC published the results of its first Broadband Consumer Survey. This national survey of 5,005 adult Americans focused on non-adopters...

  17. 75 FR 6627 - Broadband Technology Opportunities Program

    Science.gov (United States)

    2010-02-10

    ..., Washington, DC 20230; Help Desk e-mail: BroadbandUSA@usda.gov , Help Desk telephone: 1-877-508- 8364.../ . SUPPLEMENTARY INFORMATION: On January 22, 2010, NTIA published a Notice of Funds Availability (NOFA) (75 FR...

  18. Broadband V-band angular transition

    OpenAIRE

    Shcherbyna, Olga A.; Yashchyshyn, Yevhen

    2016-01-01

    A model of broadband V-band transition from a rectangular air-filled waveguide to substrate integrated waveguide has been proposed. Theoretical principles used for constructing the model of transition are also presented.

  19. Nanophotonic Design for Broadband Light Management

    Energy Technology Data Exchange (ETDEWEB)

    Kosten, Emily; Callahan, Dennis; Horowitz, Kelsey; Pala, Ragip; Atwater, Harry

    2014-10-13

    We describe nanophotonic design approaches for broadband light management including i) crossed-trapezoidal Si structures ii) Si photonic crystal superlattices, and iii) tapered and inhomogeneous diameter III-V/Si nanowire arrays.

  20. Wireless Broadband Access and Accounting Schemes

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    In this paper, we propose two wireless broadband access and accounting schemes. In both schemes, the accounting system adopts RADIUS protocol, but the access system adopts SSH and SSL protocols respectively.

  1. Decolorization of industrial synthetic dyes using engineered Pseudomonas putida cells with surface-immobilized bacterial laccase

    Directory of Open Access Journals (Sweden)

    Wang Wei

    2012-06-01

    Full Text Available Abstract Background Microbial laccases are highly useful in textile effluent dye biodegradation. However, the bioavailability of cellularly expressed or purified laccases in continuous operations is usually limited by mass transfer impediment or enzyme regeneration difficulty. Therefore, this study develops a regenerable bacterial surface-displaying system for industrial synthetic dye decolorization, and evaluates its effects on independent and continuous operations. Results A bacterial laccase (WlacD was engineered onto the cell surface of the solvent-tolerant bacterium Pseudomonas putida to construct a whole-cell biocatalyst. Ice nucleation protein (InaQ anchor was employed, and the ability of 1 to 3 tandemly aligned N-terminal repeats to direct WlacD display were compared. Immobilized WlacD was determined to be surface-displayed in functional form using Western blot analysis, immunofluorescence microscopy, flow cytometry, and whole-cell enzymatic activity assay. Engineered P. putida cells were then applied to decolorize the anthraquinone dye Acid Green (AG 25 and diazo-dye Acid Red (AR 18. The results showed that decolorization of both dyes is Cu2+- and mediator-independent, with an optimum temperature of 35°C and pH of 3.0, and can be stably performed across a temperature range of 15°C to 45°C. A high activity toward AG25 (1 g/l with relative decolorization values of 91.2% (3 h and 97.1% (18 h, as well as high activity to AR18 (1 g/l by 80.5% (3 h and 89.0% (18 h, was recorded. The engineered system exhibited a comparably high activity compared with those of separate dyes in a continuous three-round shake-flask decolorization of AG25/AR18 mixed dye (each 1 g/l. No significant decline in decolorization efficacy was noted during first two-rounds but reaction equilibriums were elongated, and the residual laccase activity eventually decreased to low levels. However, the decolorizing capacity of the system was easily retrieved

  2. Hollow plasmonic antennas for broadband SERS spectroscopy

    Directory of Open Access Journals (Sweden)

    Gabriele C. Messina

    2015-02-01

    Full Text Available The chemical environment of cells is an extremely complex and multifaceted system that includes many types of proteins, lipids, nucleic acids and various other components. With the final aim of studying these components in detail, we have developed multiband plasmonic antennas, which are suitable for highly sensitive surface enhanced Raman spectroscopy (SERS and are activated by a wide range of excitation wavelengths. The three-dimensional hollow nanoantennas were produced on an optical resist by a secondary electron lithography approach, generated by fast ion-beam milling on the polymer and then covered with silver in order to obtain plasmonic functionalities. The optical properties of these structures have been studied through finite element analysis simulations that demonstrated the presence of broadband absorption and multiband enhancement due to the unusual geometry of the antennas. The enhancement was confirmed by SERS measurements, which showed a large enhancement of the vibrational features both in the case of resonant excitation and out-of-resonance excitation. Such characteristics indicate that these structures are potential candidates for plasmonic enhancers in multifunctional opto-electronic biosensors.

  3. Biomass gasification integrated with a solid oxide fuel cell and Stirling engine

    International Nuclear Information System (INIS)

    An integrated gasification solid oxide fuel cell (SOFC) and Stirling engine for combined heat and power application is analyzed. The target for electricity production is 120 kW. Woodchips are used as gasification feedstock to produce syngas, which is then used to feed the SOFC stacks for electricity production. Unreacted hydrocarbons remaining after the SOFC are burned in a catalytic burner, and the hot off-gases from the burner are recovered in a Stirling engine for electricity and heat production. Domestic hot water is used as a heat sink for the Stirling engine. A complete balance-of-plant is designed and suggested. Thermodynamic analysis shows that a thermal efficiency of 42.4% based on the lower heating value (LHV) can be achieved if all input parameters are selected conservatively. Different parameter studies are performed to analyze the system behavior under different conditions. The analysis shows that the decreasing number of stacks from a design viewpoint, indicating that plant efficiency decreases but power production remains nearly unchanged. Furthermore, the analysis shows that there is an optimum value for the utilization factor of the SOFC for the suggested plant design with the suggested input parameters. This optimum value is approximately 65%, which is a rather modest value for SOFC. In addition, introducing a methanator increases plant efficiency slightly. If SOFC operating temperature decreases due to new technology then plant efficiency will slightly be increased. Decreasing gasifier temperature, which cannot be controlled, causes the plant efficiency to increase also. - Highlights: • Design of integrated gasification with solid oxide fuel and Stirling engine. • Important plant parameters study. • Plant running on biomass with and without methanator. • Thermodynamics of integrated gasification SOFC-Stirling engine plants

  4. Development of 3D in vitro platform technology to engineer mesenchymal stem cells

    Directory of Open Access Journals (Sweden)

    Hosseinkhani H

    2012-06-01

    Full Text Available Hossein Hosseinkhani,1 Po-Da Hong,1 Dah-Shyong Yu,2 Yi-Ru Chen,3 Diana Ickowicz,4 Ira-Yudovin Farber,4 Abraham J Domb41Graduate Institute of Biomedical Engineering, National Taiwan University of Science and Technology (TAIWANTECH, 2Nanomedicine Research Center, National Defense Medical Center, Taipei, Taiwan, 3Department of Biomedical Engineering, National Yang-Ming University, Taipei, Taiwan, 4Institute of Drug Research, The Center for Nanoscience and Nanotechnology, School of Pharmacy-Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, IsraelAbstract: This study aims to develop a three-dimensional in vitro culture system to genetically engineer mesenchymal stem cells (MSC to express bone morphogenic protein-2. We employed nanofabrication technologies borrowed from the spinning industry, such as electrospinning, to mass-produce identical building blocks in a variety of shapes and sizes to fabricate electrospun nanofiber sheets comprised of composites of poly (glycolic acid and collagen. Homogenous nanoparticles of cationic biodegradable natural polymer were formed by simple mixing of an aqueous solution of plasmid DNA encoded bone morphogenic protein-2 with the same volume of cationic polysaccharide, dextran-spermine. Rat bone marrow MSC were cultured on electrospun nanofiber sheets comprised of composites of poly (glycolic acid and collagen prior to the incorporation of the nanoparticles into the nanofiber sheets. Bone morphogenic protein-2 was significantly detected in MSC cultured on nanofiber sheets incorporated with nanoparticles after 2 days compared with MSC cultured on nanofiber sheets incorporated with naked plasmid DNA. We conclude that the incorporation of nanoparticles into nanofiber sheets is a very promising strategy to genetically engineer MSC and can be used for further applications in regenerative medicine therapy.Keywords: 3D culture, nanoparticles, nanofibers, polycations, tissue engineering

  5. Brain microvascular endothelial cell association and distribution of a 5 nm ceria engineered nanomaterial

    Directory of Open Access Journals (Sweden)

    Dan M

    2012-07-01

    Full Text Available Mo Dan,1,2 Michael T Tseng,3 Peng Wu,4 Jason M Unrine,5 Eric A Grulke,4 Robert A Yokel1,21Department of Pharmaceutical Sciences, College of Pharmacy, 2Graduate Center for Toxicology, University of Kentucky, Lexington, KY, USA; 3Departments of Anatomical Sciences and Neurobiology, University of Louisville, Louisville, KY, USA; 4Chemical and Materials Engineering Department, 5Department of Plant and Soil Science, University of Kentucky, Lexington, KY, USAPurpose: Ceria engineered nanomaterials (ENMs have current commercial applications and both neuroprotective and toxic effects. Our hypothesis is that ceria ENMs can associate with brain capillary cells and/or cross the blood–brain barrier.Methods: An aqueous dispersion of ~5 nm ceria ENM was synthesized and characterized in house. Its uptake space in the Sprague Dawley rat brain was determined using the in situ brain perfusion technique at 15 and 20 mL/minute flow rates; 30, 100, and 500 µg/mL ceria perfused for 120 seconds at 20 mL/minute; and 30 µg/mL perfused for 20, 60, and 120 seconds at 20 mL/minute. The capillary depletion method and light and electron microscopy were used to determine its capillary cell and brain parenchymal association and localization.Results: The vascular space was not significantly affected by brain perfusion flow rate or ENM, demonstrating that this ceria ENM did not influence blood–brain barrier integrity. Cerium concentrations, determined by inductively coupled plasma mass spectrometry, were significantly higher in the choroid plexus than in eight brain regions in the 100 and 500 µg/mL ceria perfusion groups. Ceria uptake into the eight brain regions was similar after 120-second perfusion of 30, 100, and 500 µg ceria/mL. Ceria uptake space significantly increased in the eight brain regions and choroid plexus after 60 versus 20 seconds, and it was similar after 60 and 120 seconds. The capillary depletion method showed 99.4% ± 1.1% of the ceria ENM associated

  6. Household Demand for Broadband Internet Service

    OpenAIRE

    Gregory Rosston; Scott Savage; Donald Waldman

    2010-01-01

    As part of the Federal Communications Commission (“FCC”) National Broadband Report to Congress, we have been asked to conduct a survey to help determine consumer valuations of different aspects of broadband Internet service. Our empirical results show that reliability and speed are important characteristics of Internet service. The representative household is willing to pay about $20 per month for more reliable service and $45-48 for an increase in speed. Willingness-to-pay for speed increase...

  7. Is European Broadband Ready for Smart Grid?

    DEFF Research Database (Denmark)

    Balachandran, Kartheepan; Pedersen, Jens Myrup

    2014-01-01

    In this short paper we compare the communication requirements for three Smart Grid scenarios with the availability of broadband and mobile communication networks in Europe. We show that only in the most demanding case - where data is collected and transmitted every second - a standard GSM....../GPRS connection is not enough. Whereas in the less demanding scenarios it is almost all of the European households that can be covered by a standard broadband technology for use with Smart Grid....

  8. Evaluation of arctic broadband surface radiation measurements

    OpenAIRE

    Matsui, N.; C. N. Long; J. Augustine; Halliwell, D.; T. Uttal; Longenecker, D.; O. Nievergall; Wendell, J.; Albee, R.

    2011-01-01

    The Arctic is a challenging environment for making in-situ radiation measurements. A standard suite of radiation sensors is typically designed to measure the total, direct and diffuse components of incoming and outgoing broadband shortwave (SW) and broadband thermal infrared, or longwave (LW) radiation. Enhancements can include various sensors for measuring irradiance in various narrower bandwidths. Many solar radiation/thermal infrared flux sensors utilize protective glass domes and some are...

  9. Broadband circularly polarized antennas for UHF SATCOM

    OpenAIRE

    Tekin, İbrahim; Tekin, Ibrahim; Manzhura, Oksana; Niver, Edip

    2011-01-01

    Novel circularly polarized (CP) antenna configurations derived from Moxon type antenna (bent dipole element over a ground plane) for broadband VHF SATCOM applications. A sequence of topologies starting from a single vertical element to two vertical elements of the Moxon arms, then widened strip arm elements were studied. Further, arms were widened to bow tie structures with bents at 900.for achieving broadband operation. Bow tie elements were further split and optimized at a certain angle to...

  10. Broadband direct RF digitization receivers

    CERN Document Server

    Jamin, Olivier

    2014-01-01

    This book discusses the trade-offs involved in designing direct RF digitization receivers for the radio frequency and digital signal processing domains.  A system-level framework is developed, quantifying the relevant impairments of the signal processing chain, through a comprehensive system-level analysis.  Special focus is given to noise analysis (thermal noise, quantization noise, saturation noise, signal-dependent noise), broadband non-linear distortion analysis, including the impact of the sampling strategy (low-pass, band-pass), analysis of time-interleaved ADC channel mismatches, sampling clock purity and digital channel selection. The system-level framework described is applied to the design of a cable multi-channel RF direct digitization receiver. An optimum RF signal conditioning, and some algorithms (automatic gain control loop, RF front-end amplitude equalization control loop) are used to relax the requirements of a 2.7GHz 11-bit ADC. A two-chip implementation is presented, using BiCMOS and 65nm...

  11. Ultra-broadband photonic internet

    Science.gov (United States)

    Romaniuk, Ryszard S.

    2011-06-01

    In this paper, there is presented a review of our today's understanding of the ultimately broadband photonic Internet. A simple calculation is presented showing the estimate of the throughput of the core photonic network branches. Optoelectronic components, circuits, systems and signals, together with analogous electronic entities and common software layers, are building blocks of the contemporary Internet. Participation of photonics in development of the physical layer in the future Internet will probably increase. The photonics leads now to a better usage of the available bandwidth (increase of the spectral efficiency measured in Bit/s/Hz), increase in the transmission rate (from Gbps, via Tbps up to probably Pbps), increase in the transmission distance without signal regeneration (in distortion compensated active optical cables), increase in energy/power efficiency measured in W/Gbps, etc. Photonics may lead, in the future, to fully transparent optical networks and, thus, to essential increase in bandwidth and network reliability. It is expected that photonics (with biochemistry, electronics and mechatronics) may build psychological and physiological interface for humans to the future global network. The following optical signal multiplexing methods were considered, which are possible without O/E/O conversion: TDM-OTDM, FDM-CO-OFDM, OCDM-OCDMA, WDM-DWDM.

  12. Multilineage co-culture of adipose-derived stem cells for tissue engineering.

    Science.gov (United States)

    Zhao, Yimu; Waldman, Stephen D; Flynn, Lauren E

    2015-07-01

    Stem cell interactions through paracrine cell signalling can regulate a range of cell responses, including metabolic activity, proliferation and differentiation. Moving towards the development of optimized tissue-engineering strategies with adipose-derived stem cells (ASCs), the focus of this study was on developing indirect co-culture models to study the effects of mature adipocytes, chondrocytes and osteoblasts on bovine ASC multilineage differentiation. For each lineage, ASC differentiation was characterized by histology, gene expression and protein expression, in the absence of key inductive differentiation factors for the ASCs. Co-culture with each of the mature cell populations was shown to successfully induce or enhance lineage-specific differentiation of the ASCs. In general, a more homogeneous but lower-level differentiation response was observed in co-culture as compared to stimulating the bovine ASCs with inductive differentiation media. To explore the role of the Wnt canonical and non-canonical signalling pathways within the model systems, the effects of the Wnt inhibitors WIF-1 and DKK-1 on multilineage differentiation in co-culture were assessed. The data indicated that Wnt signalling may play a role in mediating ASC differentiation in co-culture with the mature cell populations. PMID:23135884

  13. Armed and accurate: engineering cytotoxic T cells for eradication of leukemia

    Directory of Open Access Journals (Sweden)

    Radic Marko

    2012-02-01

    Full Text Available Abstract Translational medicine depends on a rapid and efficient exchange of results between the bench and the bedside. A recent example from the field of cancer immunotherapy highlights the essential nature of this exchange. Methods have been developed to convert a patient's cytotoxic T cells into efficient and specific killers of cancer cells in patients with leukemia. By using recombinant DNA techniques, a lentiviral vector was constructed to express chimeric antigen receptors in cytotoxic T cells from patients with advanced chronic lymphocytic leukemia. The purpose of the chimeric receptors was to direct the cytotoxic T cell activity against cells causing the cancer. The effect of infusing the engineered T cells back into the cancer patients was tested in a Phase I trial at the University of Pennsylvania, and the initial results were described in two articles from the research team of Dr. Carl June. The remarkable success of this trial should energize further applications of biotechnology in the development of new cancer immunotherapies.

  14. Extracellular matrix of dental pulp stem cells: Applications in pulp tissue engineering using somatic MSCs

    Directory of Open Access Journals (Sweden)

    Sriram eRavindran

    2014-01-01

    Full Text Available Dental Caries affects approximately 90% of the world’s population. At present, the clinical treatment for dental caries is root canal therapy. This treatment results in loss of tooth sensitivity and vitality. Tissue engineering can potentially solve this problem by enabling regeneration of a functional pulp tissue. Dental pulp stem cells (DPSCs have been shown to be an excellent source for pulp regeneration. However, limited availability of these cells hinders its potential for clinical translation. We have investigated the possibility of using somatic mesenchymal stem cells from other sources for dental pulp tissue regeneration using a biomimetic dental pulp extracellular matrix (ECM incorporated scaffold. Human periodontal ligament stem cells (PDLSCs and human bone marrow stromal cells (HMSCs were investigated for their ability to differentiate towards an odontogenic lineage. In vitro real-time PCR results coupled with histological and immunohistochemical examination of the explanted tissues confirmed the ability of PDLSCs and HMSCs to form a vascularized pulp-like tissue. These findings indicate that the dental pulp stem derived ECM scaffold stimulated odontogenic differentiation of PDLSCs and HMSCs without the need for exogenous addition of growth and differentiation factors. This study represents a translational perspective toward possible therapeutic application of using a combination of somatic stem cells and extracellular matrix for pulp regeneration.

  15. Intensity tunable infrared broadband absorbers based on VO2 phase transition using planar layered thin films

    Science.gov (United States)

    Kocer, Hasan; Butun, Serkan; Palacios, Edgar; Liu, Zizhuo; Tongay, Sefaattin; Fu, Deyi; Wang, Kevin; Wu, Junqiao; Aydin, Koray

    2015-08-01

    Plasmonic and metamaterial based nano/micro-structured materials enable spectrally selective resonant absorption, where the resonant bandwidth and absorption intensity can be engineered by controlling the size and geometry of nanostructures. Here, we demonstrate a simple, lithography-free approach for obtaining a resonant and dynamically tunable broadband absorber based on vanadium dioxide (VO2) phase transition. Using planar layered thin film structures, where top layer is chosen to be an ultrathin (20 nm) VO2 film, we demonstrate broadband IR light absorption tuning (from ~90% to ~30% in measured absorption) over the entire mid-wavelength infrared spectrum. Our numerical and experimental results indicate that the bandwidth of the absorption bands can be controlled by changing the dielectric spacer layer thickness. Broadband tunable absorbers can find applications in absorption filters, thermal emitters, thermophotovoltaics and sensing.

  16. Sensor Needs and Requirements for Fuel Cells and CIDI/SIDI Engines

    Energy Technology Data Exchange (ETDEWEB)

    Glass, R.S.

    2000-03-01

    To reduce U.S. dependence on imported oil, improve urban air quality, and decrease greenhouse gas emissions, the Department of Energy (DOE) is developing advanced vehicle technologies and fuels. Enabling technologies for fuel cell power systems and direct-injection engines are being developed by DOE through the Partnership for a New Generation of Vehicles (PNGV), a government-industry collaboration to produce vehicles having up to three times the fuel economy of conventional mid-size automobiles. Sensors have been identified as a research and development need for both fuel cell and direct-injection systems, because current sensor technologies do not adequately meet requirements. Sensors are needed for emission control, for passenger safety and comfort, to increase system lifetime, and for system performance enhancement through feedback and control. These proceedings document the results of a workshop to define sensor requirements for proton exchange membrane (PEM) fuel cell systems and direct-injection engines for automotive applications. The recommendations from this workshop will be incorporated into the multi-year R&D plan of the DOE Office of Advanced Automotive Technologies. The objectives of the workshop were to: define the requirements for sensors; establish R&D priorities; identify the technical targets and technical barriers; and facilitate collaborations among participants. The recommendations from this workshop will be incorporated into the multi-year R&D plan of the DOE Office of Advanced Automotive Technologies.

  17. Cell-mediated retraction versus hemodynamic loading - A delicate balance in tissue-engineered heart valves.

    Science.gov (United States)

    van Loosdregt, Inge A E W; Argento, Giulia; Driessen-Mol, Anita; Oomens, Cees W J; Baaijens, Frank P T

    2014-06-27

    Preclinical studies of tissue-engineered heart valves (TEHVs) showed retraction of the heart valve leaflets as major failure of function mechanism. This retraction is caused by both passive and active cell stress and passive matrix stress. Cell-mediated retraction induces leaflet shortening that may be counteracted by the hemodynamic loading of the leaflets during diastole. To get insight into this stress balance, the amount and duration of stress generation in engineered heart valve tissue and the stress imposed by physiological hemodynamic loading are quantified via an experimental and a computational approach, respectively. Stress generation by cells was measured using an earlier described in vitro model system, mimicking the culture process of TEHVs. The stress imposed by the blood pressure during diastole on a valve leaflet was determined using finite element modeling. Results show that for both pulmonary and systemic pressure, the stress imposed on the TEHV leaflets is comparable to the stress generated in the leaflets. As the stresses are of similar magnitude, it is likely that the imposed stress cannot counteract the generated stress, in particular when taking into account that hemodynamic loading is only imposed during diastole. This study provides a rational explanation for the retraction found in preclinical studies of TEHVs and represents an important step towards understanding the retraction process seen in TEHVs by a combined experimental and computational approach. PMID:24268314

  18. Engineering the Oryza sativa cell wall with rice NAC transcription factors regulating secondary wall formation

    Directory of Open Access Journals (Sweden)

    Kouki eYoshida

    2013-10-01

    Full Text Available Plant tissues that require structural rigidity synthesize a thick, strong secondary cell wall of lignin, cellulose and hemicelluloses in a complicated bridged structure. Master regulators of secondary wall synthesis were identified in dicots, and orthologs of these regulators have been identified in monocots, but regulation of secondary cell wall formation in monocots has not been extensively studied. Here we demonstrate that the rice transcription factors SECONDARY WALL NAC DOMAIN PROTEINs (SWNs can regulate secondary wall formation in rice (Oryza sativa and are potentially useful for engineering the monocot cell wall. The OsSWN1 promoter is highly active in sclerenchymatous cells of the leaf blade and less active in xylem cells. By contrast, the OsSWN2 promoter is highly active in xylem cells and less active in sclerenchymatous cells. OsSWN2 splicing variants encode two proteins; the shorter protein (OsSWN2S has very low transcriptional activation ability, but the longer protein (OsSWN2L and OsSWN1 have strong transcriptional activation ability. In rice, expression of an OsSWN2S chimeric repressor, driven by the OsSWN2 promoter, resulted in stunted growth and para-wilting (leaf rolling and browning under normal water conditions due to impaired vascular vessels. The same OsSWN2S chimeric repressor, driven by the OsSWN1 promoter, caused a reduction of cell wall thickening in sclerenchymatous cells, a drooping leaf phenotype, reduced lignin and xylose contents and increased digestibility as forage. These data suggest that OsSWNs regulate secondary wall formation in rice and manipulation of OsSWNs may enable improvements in monocotyledonous crops for forage or biofuel applications.

  19. Engineering the Oryza sativa cell wall with rice NAC transcription factors regulating secondary wall formation.

    Science.gov (United States)

    Yoshida, Kouki; Sakamoto, Shingo; Kawai, Tetsushi; Kobayashi, Yoshinori; Sato, Kazuhito; Ichinose, Yasunori; Yaoi, Katsuro; Akiyoshi-Endo, Miho; Sato, Hiroko; Takamizo, Tadashi; Ohme-Takagi, Masaru; Mitsuda, Nobutaka

    2013-01-01

    Plant tissues that require structural rigidity synthesize a thick, strong secondary cell wall of lignin, cellulose and hemicelluloses in a complicated bridged structure. Master regulators of secondary wall synthesis were identified in dicots, and orthologs of these regulators have been identified in monocots, but regulation of secondary cell wall formation in monocots has not been extensively studied. Here we demonstrate that the rice transcription factors SECONDARY WALL NAC DOMAIN PROTEINs (SWNs) can regulate secondary wall formation in rice (Oryza sativa) and are potentially useful for engineering the monocot cell wall. The OsSWN1 promoter is highly active in sclerenchymatous cells of the leaf blade and less active in xylem cells. By contrast, the OsSWN2 promoter is highly active in xylem cells and less active in sclerenchymatous cells. OsSWN2 splicing variants encode two proteins; the shorter protein (OsSWN2S) has very low transcriptional activation ability, but the longer protein (OsSWN2L) and OsSWN1 have strong transcriptional activation ability. In rice, expression of an OsSWN2S chimeric repressor, driven by the OsSWN2 promoter, resulted in stunted growth and para-wilting (leaf rolling and browning under normal water conditions) due to impaired vascular vessels. The same OsSWN2S chimeric repressor, driven by the OsSWN1 promoter, caused a reduction of cell wall thickening in sclerenchymatous cells, a drooping leaf phenotype, reduced lignin and xylose contents and increased digestibility as forage. These data suggest that OsSWNs regulate secondary wall formation in rice and manipulation of OsSWNs may enable improvements in monocotyledonous crops for forage or biofuel applications. PMID:24098302

  20. Engineering of silicon surfaces at the micro- and nanoscales for cell adhesion and migration control

    Directory of Open Access Journals (Sweden)

    Torres-Costa V

    2012-02-01

    Full Text Available Vicente Torres-Costa1, Gonzalo Martínez-Muñoz2, Vanessa Sánchez-Vaquero3, Álvaro Muñoz-Noval1, Laura González-Méndez3, Esther Punzón-Quijorna1,4, Darío Gallach-Pérez1, Miguel Manso-Silván1, Aurelio Climent-Font1,4, Josefa P García-Ruiz3, Raúl J Martín-Palma11Department of Applied Physics, 2Department of Computer Science, 3Department of Molecular Biology, 4Centre for Micro Analysis of Materials, Universidad Autónoma de Madrid, Madrid, SpainAbstract: The engineering of surface patterns is a powerful tool for analyzing cellular communication factors involved in the processes of adhesion, migration, and expansion, which can have a notable impact on therapeutic applications including tissue engineering. In this regard, the main objective of this research was to fabricate patterned and textured surfaces at micron- and nanoscale levels, respectively, with very different chemical and topographic characteristics to control cell–substrate interactions. For this task, one-dimensional (1-D and two-dimensional (2-D patterns combining silicon and nanostructured porous silicon were engineered by ion beam irradiation and subsequent electrochemical etch. The experimental results show that under the influence of chemical and morphological stimuli, human mesenchymal stem cells polarize and move directionally toward or away from the particular stimulus. Furthermore, a computational model was developed aiming at understanding cell behavior by reproducing the surface distribution and migration of human mesenchymal stem cells observed experimentally.Keywords: surface patterns, silicon, hMSCs, ion-beam patterning

  1. Cell Break: How Cell-Free Biology Is Finally Putting the Engineering Back in Bioengineering.

    Science.gov (United States)

    Fischer, Shannon

    2016-01-01

    In 2011, the California-based company Genomatica reported its success in rigging Escherichia coli microbes to convert sugar into the industrial chemical 1,4-butanediol (BDO). It was a feat of metabolic engineering: BDO is a key ingredient in the production of goods like running shoes, solvents, and spandex. At the time of the company?s announcement, 2.8 billion tons of BDO were produced every year in a multistep, fossil fuel-based process. Genomatica?s system neatly reduced all of that into a cheap, sustainable, one-step fermentation process. The company spent another year refining its technique and finally went commercial with the platform in late 2012. From start to commercialization, the process took about five years. PMID:26978845

  2. Engine-integrated solid oxide fuel cells for efficient electrical power generation on aircraft

    Science.gov (United States)

    Waters, Daniel F.; Cadou, Christopher P.

    2015-06-01

    This work investigates the use of engine-integrated catalytic partial oxidation (CPOx) reactors and solid oxide fuel cells (SOFCs) to reduce fuel burn in vehicles with large electrical loads like sensor-laden unmanned air vehicles. Thermodynamic models of SOFCs, CPOx reactors, and three gas turbine (GT) engine types (turbojet, combined exhaust turbofan, separate exhaust turbofan) are developed and checked against relevant data and source material. Fuel efficiency is increased by 4% and 8% in the 50 kW and 90 kW separate exhaust turbofan systems respectively at only modest cost in specific power (8% and 13% reductions respectively). Similar results are achieved in other engine types. An additional benefit of hybridization is the ability to provide more electric power (factors of 3 or more in some cases) than generator-based systems before encountering turbine inlet temperature limits. A sensitivity analysis shows that the most important parameters affecting the system's performance are operating voltage, percent fuel oxidation, and SOFC assembly air flows. Taken together, this study shows that it is possible to create a GT-SOFC hybrid where the GT mitigates balance of plant losses and the SOFC raises overall system efficiency. The result is a synergistic system with better overall performance than stand-alone components.

  3. Protein-engineered block-copolymers as stem cell delivery vehicles

    Science.gov (United States)

    Heilshorn, Sarah

    2015-03-01

    Stem cell transplantation is a promising therapy for a myriad of debilitating diseases and injuries; however, current delivery protocols are inadequate. Transplantation by direct injection, which is clinically preferred for its minimal invasiveness, commonly results in less than 5% cell viability, greatly inhibiting clinical outcomes. We demonstrate that mechanical membrane disruption results in significant acute loss of viability at clinically relevant injection rates. As a strategy to protect cells from these damaging forces, we show that cell encapsulation within hydrogels of specific mechanical properties will significantly improve viability. Building on these fundamental studies, we have designed a reproducible, bio-resorbable, customizable hydrogel using protein-engineering technology. In our Mixing-Induced Two-Component Hydrogel (MITCH), network assembly is driven by specific and stoichiometric peptide-peptide binding interactions. By integrating protein science methodologies with simple polymer physics models, we manipulate the polypeptide chain interactions and demonstrate the direct ability to tune the network crosslinking density, sol-gel phase behavior, and gel mechanics. This is in contrast to many other physical hydrogels, where predictable tuning of bulk mechanics from the molecular level remains elusive due to the reliance on non-specific and non-stoichiometric chain interactions for network formation. Furthermore, the hydrogel network can be easily modified to deliver a variety of bioactive payloads including growth factors, peptide drugs, and hydroxyapatite nanoparticles. Through a series of in vitro and in vivo studies, we demonstrate that these materials may significantly improve transplanted stem cell retention and function.

  4. Human Mesenchymal Stem Cells Reendothelialize Porcine Heart Valve Scaffolds: Novel Perspectives in Heart Valve Tissue Engineering

    Science.gov (United States)

    Lanuti, Paola; Serafini, Francesco; Pierdomenico, Laura; Simeone, Pasquale; Bologna, Giuseppina; Ercolino, Eva; Di Silvestre, Sara; Guarnieri, Simone; Canosa, Carlo; Impicciatore, Gianna Gabriella; Chiarini, Stella; Magnacca, Francesco; Mariggiò, Maria Addolorata; Pandolfi, Assunta; Marchisio, Marco; Di Giammarco, Gabriele; Miscia, Sebastiano

    2015-01-01

    Abstract Heart valve diseases are usually treated by surgical intervention addressed for the replacement of the damaged valve with a biosynthetic or mechanical prosthesis. Although this approach guarantees a good quality of life for patients, it is not free from drawbacks (structural deterioration, nonstructural dysfunction, and reintervention). To overcome these limitations, the heart valve tissue engineering (HVTE) is developing new strategies to synthesize novel types of valve substitutes, by identifying efficient sources of both ideal scaffolds and cells. In particular, a natural matrix, able to interact with cellular components, appears to be a suitable solution. On the other hand, the well-known Wharton's jelly mesenchymal stem cells (WJ-MSCs) plasticity, regenerative abilities, and their immunomodulatory capacities make them highly promising for HVTE applications. In the present study, we investigated the possibility to use porcine valve matrix to regenerate in vitro the valve endothelium by WJ-MSCs differentiated along the endothelial lineage, paralleled with human umbilical vein endothelial cells (HUVECs), used as positive control. Here, we were able to successfully decellularize porcine heart valves, which were then recellularized with both differentiated-WJ-MSCs and HUVECs. Data demonstrated that both cell types were able to reconstitute a cellular monolayer. Cells were able to positively interact with the natural matrix and demonstrated the surface expression of typical endothelial markers. Altogether, these data suggest that the interaction between a biological scaffold and WJ-MSCs allows the regeneration of a morphologically well-structured endothelium, opening new perspectives in the field of HVTE. PMID:26309804

  5. THE FUNCTIONAL EFFECTIVENESS OF A CELL-ENGINEERED CONSTRUCT FOR THE REGENERATION OF ARTICULAR CARTILAGE

    Directory of Open Access Journals (Sweden)

    V. I. Sevastianov

    2015-04-01

    Full Text Available The aim of this study is an analysis of the functional effectiveness of a biomedical cell product consisting of a biopolymer microheterogeneous collagen-containing hydrogel (BMCH, human adipose-derived mesenchymal stromal cells (hADMSCs, and chondrogenic induction medium in the regeneration of articular cartilage. Materials and methods. The test model of the adjuvant arthritis was used (female Soviet Chinchilla rabbits with the further development into osteoarthrosis (OA combined with the clinical, biochemical, radiological, and histochemical trials. Results. On Day 92 of the OA model it has been found that the intra-articular introduction of a BMCH with hADMSCs into the left knee joint (n = 3 30 days after the OA modeling, as opposed to the right joint (negative control, n = 3, stimulates the regenerative processes of the cartilaginous tissue structure characterized by the formation of chondrocyte «columns», the emergence of isogenic groups in the intracellular matrix and the regeneration of its structure. Upon the intra-articular introduction of a BMCH (n = 3 such effects are markedly less pronounced. Conclusions. A significant regenerative potential of a cell-engineered construct of human articular tissue (CEC ATh has been proven. It is possible to presume that biostimulating properties of CEC ATh are due to the activating effect of a biomedical cell product on the stem cell migration processes from the surrounding tissue into the injured area with their subsequent differentiation. 

  6. 3D Printing of Scaffold for Cells Delivery: Advances in Skin Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Deepti Singh

    2016-01-01

    Full Text Available Injury or damage to tissue and organs is a major health problem, resulting in about half of the world’s annual healthcare expenditure every year. Advances in the fields of stem cells (SCs and biomaterials processing have provided a tremendous leap for researchers to manipulate the dynamics between these two, and obtain a skin substitute that can completely heal the wounded areas. Although wound healing needs a coordinated interplay between cells, extracellular proteins and growth factors, the most important players in this process are the endogenous SCs, which activate the repair cascade by recruiting cells from different sites. Extra cellular matrix (ECM proteins are activated by these SCs, which in turn aid in cellular migrations and finally secretion of growth factors that can seal and heal the wounds. The interaction between ECM proteins and SCs helps the skin to sustain the rigors of everyday activity, and in an attempt to attain this level of functionality in artificial three-dimensional (3D constructs, tissue engineered biomaterials are fabricated using more advanced techniques such as bioprinting and laser assisted printing of the organs. This review provides a concise summary of the most recent advances that have been made in the area of polymer bio-fabrication using 3D bio printing used for encapsulating stem cells for skin regeneration. The focus of this review is to describe, in detail, the role of 3D architecture and arrangement of cells within this system that can heal wounds and aid in skin regeneration.

  7. CRISPR/Cas9-mediated genome engineering of CHO cell factories: application and perspectives

    DEFF Research Database (Denmark)

    Lee, Jae Seong; Grav, Lise Marie; Lewis, Nathan E.;

    2015-01-01

    repeat (CRISPR)/CRISPR-associated protein 9 (Cas9) system enables rapid,easy and efficient engineering of mammalian genomes. It has a wide range of applications frommodification of individual genes to genome-wide screening or regulation of genes. Facile genomeediting using CRISPR/Cas9 empowers...... researchers in the CHO community to elucidate the mechanisticbasis behind high level production of proteins and product quality attributes of interest. Inthis review, we describe the basis of CRISPR/Cas9-mediated genome editing and its applicationfor development of next generation CHO cell factories while...... highlighting both future perspectivesand challenges. As one of the main drivers for the CHO systems biology era, genome engineeringwith CRISPR/Cas9 will pave the way for rational design of CHO cell factories....

  8. Immobilized WNT Proteins Act as a Stem Cell Niche for Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Molly Lowndes

    2016-07-01

    Full Text Available The timing, location, and level of WNT signaling are highly regulated during embryonic development and for the maintenance of adult tissues. Consequently the ability to provide a defined and directed source of WNT proteins is crucial to fully understand its role in tissue development and to mimic its activity in vitro. Here we describe a one-step immobilization technique to covalently bind WNT3A proteins as a basal surface with easy storage and long-lasting activity. We show that this platform is able to maintain adult and embryonic stem cells while also being adaptable for 3D systems. Therefore, this platform could be used for recapitulating specific stem cell niches with the goal of improving tissue engineering.

  9. Photovoltaic Engineering Testbed: A Facility for Space Calibration and Measurement of Solar Cells on the International Space Station

    Science.gov (United States)

    Landis, Geoffrey A.; Bailey, Sheila G.; Jenkins, Phillip; Sexton, J. Andrew; Scheiman, David; Christie, Robert; Charpie, James; Gerber, Scott S.; Johnson, D. Bruce

    2001-01-01

    The Photovoltaic Engineering Testbed ("PET") is a facility to be flown on the International Space Station to perform calibration, measurement, and qualification of solar cells in the space environment and then returning the cells to Earth for laboratory use. PET will allow rapid turnaround testing of new photovoltaic technology under AM0 conditions.

  10. Acute pergolide exposure stiffens engineered valve interstitial cell tissues and reduces contractility in vitro.

    Science.gov (United States)

    Capulli, Andrew K; MacQueen, Luke A; O'Connor, Blakely B; Dauth, Stephanie; Parker, Kevin Kit

    2016-01-01

    Medications based on ergoline-derived dopamine and serotonin agonists are associated with off-target toxicities that include valvular heart disease (VHD). Reports of drug-induced VHD resulted in the withdrawal of appetite suppressants containing fenfluramine and phentermine from the US market in 1997 and pergolide, a Parkinson's disease medication, in 2007. Recent evidence suggests that serotonin receptor activity affected by these medications modulates cardiac valve interstitial cell activation and subsequent valvular remodeling, which can lead to cardiac valve fibrosis and dysfunction similar to that seen in carcinoid heart disease. Failure to identify these risks prior to market and continued use of similar drugs reaffirm the need to improve preclinical evaluation of drug-induced VHD. Here, we present two complimentary assays to measure stiffness and contractile stresses generated by engineered valvular tissues in vitro. As a case study, we measured the effects of acute (24 h) pergolide exposure to engineered porcine aortic valve interstitial cell (AVIC) tissues. Pergolide exposure led to increased tissue stiffness, but it decreased both basal and active contractile tone stresses generated by AVIC tissues. Pergolide exposure also disrupted AVIC tissue organization (i.e., tissue anisotropy), suggesting that the mechanical properties and contractile functionality of these tissues are governed by their ability to maintain their structure. We expect further use of these assays to identify off-target drug effects that alter the phenotypic balance of AVICs, disrupt their ability to maintain mechanical homeostasis, and lead to VHD. PMID:27174867

  11. Before the endless forms: embodied model of transition from single cells to aggregates to ecosystem engineering.

    Science.gov (United States)

    Solé, Ricard V; Valverde, Sergi

    2013-01-01

    The emergence of complex multicellular systems and their associated developmental programs is one of the major problems of evolutionary biology. The advantages of cooperation over individuality seem well known but it is not clear yet how such increase of complexity emerged from unicellular life forms. Current multicellular systems display a complex cell-cell communication machinery, often tied to large-scale controls of body size or tissue homeostasis. Some unicellular life forms are simpler and involve groups of cells cooperating in a tissue-like fashion, as it occurs with biofilms. However, before true gene regulatory interactions were widespread and allowed for controlled changes in cell phenotypes, simple cellular colonies displaying adhesion and interacting with their environments were in place. In this context, models often ignore the physical embedding of evolving cells, thus leaving aside a key component. The potential for evolving pre-developmental patterns is a relevant issue: how far a colony of evolving cells can go? Here we study these pre-conditions for morphogenesis by using CHIMERA, a physically embodied computational model of evolving virtual organisms in a pre-Mendelian world. Starting from a population of identical, independent cells moving in a fluid, the system undergoes a series of changes, from spatial segregation, increased adhesion and the development of generalism. Eventually, a major transition occurs where a change in the flow of nutrients is triggered by a sub-population. This ecosystem engineering phenomenon leads to a subsequent separation of the ecological network into two well defined compartments. The relevance of these results for evodevo and its potential ecological triggers is discussed. PMID:23596506

  12. Design of broadband omnidirectional antireflection coatings using ant colony algorithm.

    Science.gov (United States)

    Guo, X; Zhou, H Y; Guo, S; Luan, X X; Cui, W K; Ma, Y F; Shi, L

    2014-06-30

    Optimization method which is based on the ant colony algorithm (ACA) is described to optimize antireflection (AR) coating system with broadband omnidirectional characteristics for silicon solar cells incorporated with the solar spectrum (AM1.5 radiation). It's the first time to use ACA method for optimizing the AR coating system. In this paper, for the wavelength range from 400 nm to 1100 nm, the optimized three-layer AR coating system could provide an average reflectance of 2.98% for incident angles from Raveθ+ to 80° and 6.56% for incident angles from 0° to 90°. PMID:24978076

  13. Broadband Active Phase Shifter GaAs MMIC

    OpenAIRE

    Duême, Ph.; Dequen, Th.; Funck, R.; Caillon, B.; Guerbeur, G.

    2002-01-01

    A broadband multifunction MMIC, achieving combined amplification and phase shift, has been developed on 2 (3.2 x 4) mm² chips using the UMS PH25 process. The frequency range is as large as characterised by a ratio of Fmax/Fmin = 6. The 5 bit phase shifter section is based on switched "all-pass" cells. The amplification function is realised through active switches consuming less than a total of 40 mA under 3V and providing an overall gain of about +6 dB.

  14. Modeling of Broadband Liners Applied to the Advanced Noise Control Fan

    Science.gov (United States)

    Nark, Douglas M.; Jones, Michael G.; Sutliff, Daniel L.

    2015-01-01

    The broadband component of fan noise has grown in relevance with an increase in bypass ratio and incorporation of advanced fan designs. Therefore, while the attenuation of fan tones remains a major factor in engine nacelle acoustic liner design, the simultaneous reduction of broadband fan noise levels has received increased interest. As such, a previous investigation focused on improvements to an established broadband acoustic liner optimization process using the Advanced Noise Control Fan (ANCF) rig as a demonstrator. Constant-depth, double-degree of freedom and variable-depth, multi-degree of freedom liner designs were carried through design, fabrication, and testing. This paper addresses a number of areas for further research identified in the initial assessment of the ANCF study. Specifically, incident source specification and uncertainty in some aspects of the predicted liner impedances are addressed. This information is incorporated in updated predictions of the liner performance and comparisons with measurement are greatly improved. Results illustrate the value of the design process in concurrently evaluating the relative costs/benefits of various liner designs. This study also provides further confidence in the integrated use of duct acoustic propagation/radiation and liner modeling tools in the design and evaluation of novel broadband liner concepts for complex engine configurations.

  15. 324 Radiochemical engineering cells and high level vault tanks mixed waste compliance status

    International Nuclear Information System (INIS)

    The 324 Building in the Hanford 300 Area contains Radiochemical Engineering Cells and High Level Vault tanks (the open-quotes REC/HLVclose quotes) for research and development activities involving radioactive materials. Radioactive mixed waste within this research installation, found primarily in B-Cell and three of the high level vault tanks, is subject to RCRA/DWR (open-quotes RCRAclose quotes) regulations for storage. This white paper provides a baseline RCRA compliance summary of MW management in the REC/HLV, based on best available knowledge. The REC/HLV compliance project, of which this paper is a part, is intended to achieve the highest degree of compliance practicable given the special technical difficulties of managing high activity radioactive materials, and to assure protection of human health and safety and the environment. The REC/HLV was constructed in 1965 to strict standards for the safe management of highly radioactive materials. Mixed waste in the REC/HLV consists of discarded tools and equipment, dried feed stock from nuclear waste melting experiments, contaminated particulate matter, and liquid feed stock from various experimental programs in the vault tanks. B-Cell contains most of these materials. Total radiological inventory in B-Cell is estimated at 3 MCi, about half of which is potentially open-quotes dispersibleclose quotes, that is, it is in small pieces or mobile particles. Most of the mixed waste currently in the REC/HLV was generated or introduced before mixed wastes were subjected to RCRA in 1987

  16. Direct Mechanical Stimulation of Stem Cells: A Beating Electromechanically Active Scaffold for Cardiac Tissue Engineering.

    Science.gov (United States)

    Gelmi, Amy; Cieslar-Pobuda, Artur; de Muinck, Ebo; Los, Marek; Rafat, Mehrdad; Jager, Edwin W H

    2016-06-01

    The combination of stem cell therapy with a supportive scaffold is a promising approach to improving cardiac tissue engineering. Stem cell therapy can be used to repair nonfunctioning heart tissue and achieve myocardial regeneration, and scaffold materials can be utilized in order to successfully deliver and support stem cells in vivo. Current research describes passive scaffold materials; here an electroactive scaffold that provides electrical, mechanical, and topographical cues to induced human pluripotent stem cells (iPS) is presented. The poly(lactic-co-glycolic acid) fiber scaffold coated with conductive polymer polypyrrole (PPy) is capable of delivering direct electrical and mechanical stimulation to the iPS. The electroactive scaffolds demonstrate no cytotoxic effects on the iPS as well as an increased expression of cardiac markers for both stimulated and unstimulated protocols. This study demonstrates the first application of PPy as a supportive electroactive material for iPS and the first development of a fiber scaffold capable of dynamic mechanical actuation. PMID:27126086

  17. Analyzing Biological Performance of 3D-Printed, Cell-Impregnated Hybrid Constructs for Cartilage Tissue Engineering.

    Science.gov (United States)

    Izadifar, Zohreh; Chang, Tuanjie; Kulyk, William; Chen, Xiongbiao; Eames, B Frank

    2016-03-01

    Three-dimensional (3D) bioprinting of hybrid constructs is a promising biofabrication method for cartilage tissue engineering because a synthetic polymer framework and cell-impregnated hydrogel provide structural and biological features of cartilage, respectively. During bioprinting, impregnated cells may be subjected to high temperatures (caused by the adjacent melted polymer) and process-induced mechanical forces, potentially compromising cell function. This study addresses these biofabrication issues, evaluating the heat distribution of printed polycaprolactone (PCL) strands and the rheological property and structural stability of alginate hydrogels at various temperatures and concentrations. The biocompatibility of parameters from these studies was tested by culturing 3D hybrid constructs bioprinted with primary cells from embryonic chick cartilage. During initial two-dimensional culture expansion of these primary cells, two morphologically and molecularly distinct cell populations ("rounded" and "fibroblastic") were isolated. The biological performance of each population was evaluated in 3D hybrid constructs separately. The cell viability, proliferation, and cartilage differentiation were observed at high levels in hybrid constructs of both cell populations, confirming the validity of these 3D bioprinting parameters for effective cartilage tissue engineering. Statistically significant performance variations were observed, however, between the rounded and fibroblastic cell populations. Molecular and morphological data support the notion that such performance differences may be attributed to the relative differentiation state of rounded versus fibroblastic cells (i.e., differentiated chondrocytes vs. chondroprogenitors, respectively), which is a relevant issue for cell-based tissue engineering strategies. Taken together, our study demonstrates that bioprinting 3D hybrid constructs of PCL and cell-impregnated alginate hydrogel is a promising approach for

  18. The Future of Cell Therapy and Tissue Engineering in Cardiovascular Disease: The New Era of Biological Therapeutics

    OpenAIRE

    Heydarkhan-Hagvall, Sepideh; Nsair, Ali; Beygui, Ramin E.; Shemin, Richard J

    2010-01-01

    The use of living cells as a therapeutic option presents several challenges including identification of a suitable source, development of adequate derivation, maintenance and differentiation methods, and very importantly proof of safety and efficacy. One of the major issues for cardiovascular tissue engineering is determining the ideal cell type for use in regenerative therapies.Many clinical trials have used bone marrow derived mononuclear cells (BM-MNC) (Schächinger V 2006). These clinical ...

  19. Impairments of cells and genomic DNA by environmentally transformed engineered nanomaterials

    Science.gov (United States)

    Jones, Philip; Sugino, Sakiko; Yamamura, Shohei; Lacy, Fred; Biju, Vasudevanpillai

    2013-09-01

    Enormous increase in the production of nanomaterials and their growing applications in the device technology, biotechnology and biomedical areas suggest the need for developing models for predicting the environmental health and safety (EHS) risks posed by such nanomaterials. We hypothesize that CdSe quantum dots (QDs) and ZnO nanoparticles (NPs) encompassed in liposomes or not and transformed by simulated solar UV light can be model systems for studying the environmental toxicity of engineered nanomaterials. In this study, human lung epithelial adenocarcinoma cells (H1650) are exposed to photoirradiated CdSe QDs or ZnO nanopowder included or not in liposomes. The release of cadmium and zinc ions from the nanomaterials exposed to solar simulated UV radiation is detected and quantified by measuring the steady-state and time resolved fluorescence of the metal ion sensor tetracarboxyphenylporphyrin (TCPP) or the commercial Measure iT Pd/Cd sensor. Viability of cells treated with nanomaterials exposed to solar simulated UV radiation for different durations is measured by MTT assay. Enhanced etching of the nanoparticles exposed to solar simulated UV radiation results in the release of toxic levels of heavy metal ions, which considerably lower the viability of H1650 cells is due to the deactivation of DNA repair enzymes as evidenced by the pinching off of nuclear DNA in comet assays and DNA samples in electrophoresis. Results from this study highlight the need to obtain not only quantitative information about the environmental risks posed by engineered nanomaterials but also environment friendly nanomaterials for practical applications.Enormous increase in the production of nanomaterials and their growing applications in the device technology, biotechnology and biomedical areas suggest the need for developing models for predicting the environmental health and safety (EHS) risks posed by such nanomaterials. We hypothesize that CdSe quantum dots (QDs) and ZnO nanoparticles

  20. Stem cell differentiation on electrospun nanofibrous substrates for vascular tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Jia, Lin [Key Laboratory of Textile Science and Technology, Ministry of Education, College of Textiles, Donghua University, No. 2999 North Renmin Road, Songjiang, Shanghai 201620 (China); Center for Nanofibers and Nanotechnology, E3-05-14, Nanoscience and Nanotechnology Initiative, Faculty of Engineering, National University of Singapore, 2 Engineering Drive 3, Singapore 117576 (Singapore); Prabhakaran, Molamma P., E-mail: nnimpp@nus.edu.sg [Center for Nanofibers and Nanotechnology, E3-05-14, Nanoscience and Nanotechnology Initiative, Faculty of Engineering, National University of Singapore, 2 Engineering Drive 3, Singapore 117576 (Singapore); Qin, Xiaohong, E-mail: xhqin@dhu.edu.cn [Key Laboratory of Textile Science and Technology, Ministry of Education, College of Textiles, Donghua University, No. 2999 North Renmin Road, Songjiang, Shanghai 201620 (China); Ramakrishna, Seeram [Center for Nanofibers and Nanotechnology, E3-05-14, Nanoscience and Nanotechnology Initiative, Faculty of Engineering, National University of Singapore, 2 Engineering Drive 3, Singapore 117576 (Singapore)

    2013-12-01

    Nanotechnology has enabled the engineering of a variety of materials to meet the current challenges and requirements in vascular tissue regeneration. In our study, poly-L-lactide (PLLA) and hybrid PLLA/collagen (PLLA/Coll) nanofibers (3:1 and 1:1) with fiber diameters of 210 to 430 nm were fabricated by electrospinning. Their morphological, chemical and mechanical characterizations were carried out using scanning electron microscopy (SEM), attenuated total reflectance Fourier transform infrared (ATR-FTIR), and tensile instrument, respectively. Bone marrow derived mesenchymal stem cells (MSCs) seeded on electrospun nanofibers that are capable of differentiating into vascular cells have great potential for repair of the vascular system. We investigated the potential of MSCs for vascular cell differentiation in vitro on electrospun PLLA/Coll nanofibrous scaffolds using endothelial differentiation media. After 20 days of culture, MSC proliferation on PLLA/Coll(1:1) scaffolds was found 256% higher than the cell proliferation on PLLA scaffolds. SEM images showed that the MSC differentiated endothelial cells on PLLA/Coll scaffolds showed cobblestone morphology in comparison to the fibroblastic type of undifferentiated MSCs. The functionality of the cells in the presence of ‘endothelial induction media’, was further demonstrated from the immunocytochemical analysis, where the MSCs on PLLA/Coll (1:1) scaffolds differentiated to endothelial cells and expressed the endothelial cell specific proteins such as platelet endothelial cell adhesion molecule-1 (PECAM-1 or CD31) and Von Willebrand factor (vWF). From the results of the SEM analysis and protein expression studies, we concluded that the electrospun PLLA/Coll nanofibers could mimic the native vascular ECM environment and might be promising substrates for potential application towards vascular regeneration. - Highlights: • PLLA and PLLA/Coll nanofibers were electrospun. • Incorporation of collagen reduced fiber

  1. Stem cell differentiation on electrospun nanofibrous substrates for vascular tissue engineering

    International Nuclear Information System (INIS)

    Nanotechnology has enabled the engineering of a variety of materials to meet the current challenges and requirements in vascular tissue regeneration. In our study, poly-L-lactide (PLLA) and hybrid PLLA/collagen (PLLA/Coll) nanofibers (3:1 and 1:1) with fiber diameters of 210 to 430 nm were fabricated by electrospinning. Their morphological, chemical and mechanical characterizations were carried out using scanning electron microscopy (SEM), attenuated total reflectance Fourier transform infrared (ATR-FTIR), and tensile instrument, respectively. Bone marrow derived mesenchymal stem cells (MSCs) seeded on electrospun nanofibers that are capable of differentiating into vascular cells have great potential for repair of the vascular system. We investigated the potential of MSCs for vascular cell differentiation in vitro on electrospun PLLA/Coll nanofibrous scaffolds using endothelial differentiation media. After 20 days of culture, MSC proliferation on PLLA/Coll(1:1) scaffolds was found 256% higher than the cell proliferation on PLLA scaffolds. SEM images showed that the MSC differentiated endothelial cells on PLLA/Coll scaffolds showed cobblestone morphology in comparison to the fibroblastic type of undifferentiated MSCs. The functionality of the cells in the presence of ‘endothelial induction media’, was further demonstrated from the immunocytochemical analysis, where the MSCs on PLLA/Coll (1:1) scaffolds differentiated to endothelial cells and expressed the endothelial cell specific proteins such as platelet endothelial cell adhesion molecule-1 (PECAM-1 or CD31) and Von Willebrand factor (vWF). From the results of the SEM analysis and protein expression studies, we concluded that the electrospun PLLA/Coll nanofibers could mimic the native vascular ECM environment and might be promising substrates for potential application towards vascular regeneration. - Highlights: • PLLA and PLLA/Coll nanofibers were electrospun. • Incorporation of collagen reduced fiber

  2. Interface Engineering of Organic Schottky Barrier Solar Cells and Its Application in Enhancing Performances of Planar Heterojunction Solar Cells

    Science.gov (United States)

    Jin, Fangming; Su, Zisheng; Chu, Bei; Cheng, Pengfei; Wang, Junbo; Zhao, Haifeng; Gao, Yuan; Yan, Xingwu; Li, Wenlian

    2016-05-01

    In this work, we describe the performance of organic Schottky barrier solar cells with the structure of ITO/molybdenum oxide (MoOx)/boron subphthalocyanine chloride (SubPc)/bathophenanthroline (BPhen)/Al. The SubPc-based Schottky barrier solar cells exhibited a short-circuit current density (Jsc) of 2.59 mA/cm2, an open-circuit voltage (Voc) of 1.06 V, and a power conversion efficiency (PCE) of 0.82% under simulated AM1.5 G solar illumination at 100 mW/cm2. Device performance was substantially enhanced by simply inserting thin organic hole transport material into the interface of MoOx and SubPc. The optimized devices realized a 180% increase in PCE of 2.30% and a peak Voc as high as 1.45 V was observed. We found that the improvement is due to the exciton and electron blocking effect of the interlayer and its thickness plays a vital role in balancing charge separation and suppressing quenching effect. Moreover, applying such interface engineering into MoOx/SubPc/C60 based planar heterojunction cells substantially enhanced the PCE of the device by 44%, from 3.48% to 5.03%. Finally, we also investigated the requirements of the interface material for Schottky barrier modification.

  3. Interface Engineering of Organic Schottky Barrier Solar Cells and Its Application in Enhancing Performances of Planar Heterojunction Solar Cells

    Science.gov (United States)

    Jin, Fangming; Su, Zisheng; Chu, Bei; Cheng, Pengfei; Wang, Junbo; Zhao, Haifeng; Gao, Yuan; Yan, Xingwu; Li, Wenlian

    2016-01-01

    In this work, we describe the performance of organic Schottky barrier solar cells with the structure of ITO/molybdenum oxide (MoOx)/boron subphthalocyanine chloride (SubPc)/bathophenanthroline (BPhen)/Al. The SubPc-based Schottky barrier solar cells exhibited a short-circuit current density (Jsc) of 2.59 mA/cm2, an open-circuit voltage (Voc) of 1.06 V, and a power conversion efficiency (PCE) of 0.82% under simulated AM1.5 G solar illumination at 100 mW/cm2. Device performance was substantially enhanced by simply inserting thin organic hole transport material into the interface of MoOx and SubPc. The optimized devices realized a 180% increase in PCE of 2.30% and a peak Voc as high as 1.45 V was observed. We found that the improvement is due to the exciton and electron blocking effect of the interlayer and its thickness plays a vital role in balancing charge separation and suppressing quenching effect. Moreover, applying such interface engineering into MoOx/SubPc/C60 based planar heterojunction cells substantially enhanced the PCE of the device by 44%, from 3.48% to 5.03%. Finally, we also investigated the requirements of the interface material for Schottky barrier modification. PMID:27185635

  4. Using qualimetric engineering and extremal analysis to optimize a proton exchange membrane fuel cell stack

    International Nuclear Information System (INIS)

    Highlights: • We consider the optimal configuration of a PEMFC stack. • We utilize qualimetric engineering tools (Taguchi screening, regression analysis). • We achieve analytical solution on a restructured power-law fitting. • We discuss the Pt-cost involvement in the unit and area minimization scope. - Abstract: The optimal configuration of the proton exchange membrane fuel-cell (PEMFC) stack has received attention recently because of its potential use as an isolated energy distributor for household needs. In this work, the original complex problem for generating an optimal PEMFC stack based on the number of cell units connected in series and parallel arrangements as well as on the cell area is revisited. A qualimetric engineering strategy is formulated which is based on quick profiling the PEMFC stack voltage response. Stochastic screening is initiated by employing an L9(33) Taguchi-type OA for partitioning numerically the deterministic expression of the output PEMFC stack voltage such that to facilitate the sizing of the magnitude of the individual effects. The power and current household specifications for the stack system are maintained at the typical settings of 200 W at 12 V, respectively. The minimization of the stack total-area requirement becomes explicit in this work. The relationship of cell voltage against cell area is cast into a power-law model by regression fitting that achieves a coefficient of determination value of 99.99%. Thus, the theoretical formulation simplifies into a non-linear extremal problem with a constrained solution due to a singularity which is solved analytically. The optimal solution requires 22 cell units connected in series where each unit is designed with an area value of 151.4 cm2. It is also demonstrated how to visualize the optimal solution using the graphical method of operating lines. The total area of 3270.24 cm2 becomes a new benchmark for the optimal design of the studied PEMFC stack configuration. It is

  5. Scaffold- and Cell System-Based Bone Grafts in Tissue Engineering (Review

    Directory of Open Access Journals (Sweden)

    Kuznetsova D.S.

    2014-12-01

    Full Text Available The review considers the current trends in tissue engineering including maxillofacial surgery based on the use of scaffolds, autologous stem cells and bioactive substances. The authors have shown the advantages and disadvantages of basic materials used for scaffold synthesis — three-dimensional porous or fiber matrices serving as a mechanical frame for cells; among such materials there are natural polymers (collagen, cellulose, fibronectin, chitosan, alginate and agarose, fibroin, synthetic polymers (polylactide, polyglycolide, polycaprolactone, polyvinyl alcohol and bioceramics (hydroxyapatite, tricalcium phosphate and bioactive glasses. There have been demonstrated the matrix techniques, special attention being paid to innovative technologies of rapid prototyping — the process of 3D-imaging according to a digital model. The most applicable of these techniques for biopolymers are laser stereolithography, selective laser sintering, fused deposition modeling, and 3D-printing. Great emphasis has been put on the use of bioactive substances in the process of obtaining scaffold-based bioengineered constructions — setting of stem cells on matrices before their transplantation to the defect area. Special attention has been given to a current trend of cellular biology — the application of multipotent mesenchymal stromal cells (most common marrow cells used in bone tissue regeneration, in particular, the available sources of their isolation and the variants of directed osteogenic differentiation have been presented. The review covers the characteristics and aims of bioactive substance inclusion in scaffold structure — not only to induce osteogenic differentiation, but also to attract new stem cells of a carrier, as well as promote angiogenesis.

  6. Further Development and Assessment of a Broadband Liner Optimization Process

    Science.gov (United States)

    Nark, Douglas M.; Jones, Michael G.; Sutliff, Daniel L.

    2016-01-01

    The utilization of advanced fan designs (including higher bypass ratios) and shorter engine nacelles has highlighted a need for increased fan noise reduction over a broader frequency range. Thus, improved broadband liner designs must account for these constraints and, where applicable, take advantage of advanced manufacturing techniques that have opened new possibilities for novel configurations. This work focuses on the use of an established broadband acoustic liner optimization process to design a variable-depth, multi-degree of freedom liner for a high speed fan. Specifically, in-duct attenuation predictions with a statistical source model are used to obtain optimum impedance spectra over the conditions of interest. The predicted optimum impedance information is then used with acoustic liner modeling tools to design a liner aimed at producing impedance spectra that most closely match the predicted optimum values. The multi-degree of freedom design is carried through design, fabrication, and testing. In-duct attenuation predictions compare well with measured data and the multi-degree of freedom liner is shown to outperform a more conventional liner over a range of flow conditions. These promising results provide further confidence in the design tool, as well as the enhancements made to the overall design process.

  7. Helicity multiplexed broadband metasurface holograms

    OpenAIRE

    Wen, Dandan; Yue, Fuyong; Li, Guixin; Zheng, Guoxing; Chan, Kinlong; Chen, Shumei; Chen, Ming; Li, King Fai; Wong, Polis Wing Han; Cheah, Kok Wai; Yue Bun Pun, Edwin; Shuang ZHANG; Chen, Xianzhong

    2015-01-01

    Metasurfaces are engineered interfaces that contain a thin layer of plasmonic or dielectric nanostructures capable of manipulating light in a desirable manner. Advances in metasurfaces have led to various practical applications ranging from lensing to holography. Metasurface holograms that can be switched by the polarization state of incident light have been demonstrated for achieving polarization multiplexed functionalities. However, practical application of these devices has been limited by...

  8. Role of metal/silicon semiconductor contact engineering for enhanced output current in micro-sized microbial fuel cells

    KAUST Repository

    Mink, Justine E.

    2013-11-25

    We show that contact engineering plays an important role to extract the maximum performance from energy harvesters like microbial fuel cells (MFCs). We experimented with Schottky and Ohmic methods of fabricating contact areas on silicon in an MFC contact material study. We utilized the industry standard contact material, aluminum, as well as a metal, whose silicide has recently been recognized for its improved performance in smallest scale integration requirements, cobalt. Our study shows that improvements in contact engineering are not only important for device engineering but also for microsystems. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Microbial desalination cell for enhanced biodegradation of waste engine oil using a novel bacterial strain Bacillus subtilis moh3.

    Science.gov (United States)

    Sabina, K; Fayidh, Mohammed A; Archana, G; Sivarajan, M; Babuskin, S; Babu, P Azhagu Saravana; Radha, K Krishnan; Sukumar, M

    2014-01-01

    Microbial desalination cell (MDC) is a bioelectrochemical system developed recently from microbial fuel cells (MFCs), for producing green energy from organic wastes along with desalination of saltwater. MDC is proved to be a better performer than MFC in terms of power output and chemical oxygen demand removal, with desalination as an additional feature. This study investigates the application potential of MDC for integrated biodegradation of waste engine oil. This study showed, for the first time, that waste engine oil could be used as an organic substrate in MDC, achieving biodegradation of engine oil along with considerable desalination and power production. Utilization of these wastes in MDC can protect the environment from waste engine oil contamination. Indigenous oil-degrading bacteria were isolated and identified from engine oil contaminated sludge. Degradation of waste engine oil by these novel isolates was studied in batch cultures and optimized the growth conditions. The same cultures when used in MDC, gave enhanced biodegradation (70.1 +/- 0.5%) along with desalination (68.3 +/- 0.6%) and power production (3.1 +/- 0.3 mW/m2). Fourier transform-infrared spectroscopy and gas chromatography-mass spectrometry analyses were performed to characterize the degradation metabolites in the anolyte of MDC which clearly indicated the biodegradation of long chain, branched and cyclic hydrocarbons present in waste engine oil. PMID:25145172

  10. Broadband antireflection coatings for multifunctional avionic displays

    Science.gov (United States)

    Kumari, Neelam; Kumar, Mukesh; Rao, P. K.; Karar, Vinod; Sharma, Amit Lochan

    2015-06-01

    Broadband Multilayer Antireflection (AR) coatings markedly improve the transmission efficiency of any optical component such as lens, prism, beam-splitter, beam combiner or a window. By reducing surface reflections over a wide wavelength range, broadband antireflection coatings improve transmission and enhance contrast which is desired in avionic displays. The broadband antireflection coating consisting of MgF2, ZrO2 and Al2O3 were designed to cover the whole visible spectrum and fabricated on optical grade glass substrate. The optical characterization of these coatings indicates reduction of the reflection to 2.28% as compared to 8.5 % at 545 nm (i.e. design wavelength of most avionic displays) for bare substrate making them useful in optical displays for avionic applications.

  11. Participation in the broadband society in Denmark

    DEFF Research Database (Denmark)

    Falch, Morten; Henten, Anders; Skouby, Knud Erik

    2009-01-01

    The purpose of the paper is to provide an empirical overview of broadband developments in Denmark. The overview includes sections on coverage and penetration, connection speeds, retail prices, competition, interconnection prices, and residential access to Internet. The documentation shows...... passed the threshold set by the EU with respect to the relevance of initiating a discussion on the implementation of a universal service obligation on broadband. As documented in the paper, there are groups among primarily the elderly and the unemployed who do not have Internet access. Their own...... that Denmark is doing well in most international comparisons, but retail prices are still relatively high and connection speeds are lower than the best performing countries. In terms of households, approximately three quarters have broadband access. Denmark - and a number of other countries as well - has thus...

  12. Time-lapse imaging of primary preneoplastic mammary epithelial cells derived from genetically engineered mouse models of breast cancer.

    Science.gov (United States)

    Nakles, Rebecca E; Millman, Sarah L; Cabrera, M Carla; Johnson, Peter; Mueller, Susette; Hoppe, Philipp S; Schroeder, Timm; Furth, Priscilla A

    2013-01-01

    Time-lapse imaging can be used to compare behavior of cultured primary preneoplastic mammary epithelial cells derived from different genetically engineered mouse models of breast cancer. For example, time between cell divisions (cell lifetimes), apoptotic cell numbers, evolution of morphological changes, and mechanism of colony formation can be quantified and compared in cells carrying specific genetic lesions. Primary mammary epithelial cell cultures are generated from mammary glands without palpable tumor. Glands are carefully resected with clear separation from adjacent muscle, lymph nodes are removed, and single-cell suspensions of enriched mammary epithelial cells are generated by mincing mammary tissue followed by enzymatic dissociation and filtration. Single-cell suspensions are plated and placed directly under a microscope within an incubator chamber for live-cell imaging. Sixteen 650 μm x 700 μm fields in a 4x4 configuration from each well of a 6-well plate are imaged every 15 min for 5 days. Time-lapse images are examined directly to measure cellular behaviors that can include mechanism and frequency of cell colony formation within the first 24 hr of plating the cells (aggregation versus cell proliferation), incidence of apoptosis, and phasing of morphological changes. Single-cell tracking is used to generate cell fate maps for measurement of individual cell lifetimes and investigation of cell division patterns. Quantitative data are statistically analyzed to assess for significant differences in behavior correlated with specific genetic lesions. PMID:23425702

  13. Broadband dispersion-engineered microresonator on a chip

    Science.gov (United States)

    Yang, Ki Youl; Beha, Katja; Cole, Daniel C.; Yi, Xu; Del'Haye, Pascal; Lee, Hansuek; Li, Jiang; Oh, Dong Yoon; Diddams, Scott A.; Papp, Scott B.; Vahala, Kerry J.

    2016-05-01

    The control of dispersion in fibre optical waveguides is of critical importance to optical fibre communications systems and more recently for continuum generation from the ultraviolet to the mid-infrared. The wavelength at which the group velocity dispersion crosses zero can be set by varying the fibre core diameter or index step. Moreover, sophisticated methods to manipulate higher-order dispersion so as to shape and even flatten the dispersion over wide bandwidths are possible using multi-cladding fibres. Here we introduce design and fabrication techniques that allow analogous dispersion control in chip-integrated optical microresonators, and thereby demonstrate higher-order, wide-bandwidth dispersion control over an octave of spectrum. Importantly, the fabrication method we employ for dispersion control simultaneously permits optical Q factors above 100 million, which is critical for the efficient operation of nonlinear optical oscillators. Dispersion control in high-Q systems has become of great importance in recent years with increased interest in chip-integrable optical frequency combs.

  14. Dispersion engineering silicon nitride waveguides for broadband nonlinear frequency conversion

    NARCIS (Netherlands)

    Epping, J.P.

    2015-01-01

    In this thesis, we investigated nonlinear frequency conversion of optical wavelengths using integrated silicon nitride (Si3N4) waveguides. Two nonlinear conversion schemes were considered: seeded four-wave mixing and supercontinuum generation. The first—seeded four-wave mixing—is investigated by a n

  15. Broadband Multilayered Array Antenna with EBG Reflector

    Directory of Open Access Journals (Sweden)

    P. Chen

    2013-01-01

    Full Text Available Most broadband microstrip antennae are implemented in the form of slot structure or laminate structure. The impedance bandwidth is broadened, but meanwhile, the sidelobe of the directivity pattern and backlobe level are enlarged. A broadband stacked slot coupling microstrip antenna array with EBG structure reflector is proposed. Test results indicate that the proposed reflector structure can effectively improve the directivity pattern of stacked antenna and aperture coupled antenna, promote the front-to-back ratio, and reduce the thickness of the antenna. Therefore, it is more suitable to be applied as an airborne antenna.

  16. Current and future regenerative medicine - principles, concepts, and therapeutic use of stem cell therapy and tissue engineering in equine medicine

    DEFF Research Database (Denmark)

    Koch, Thomas Gadegaard; Berg, Lise Charlotte; Betts, Dean H.

    2009-01-01

    be recorded and reported.Stem cell and tissue engineering research in the horse has exciting comparative and equine specific perspectives that most likely will benefit the health of horses and humans. Controlled, well-designed studies are needed to move this new equine research field forward.......This paper provides a bird's-eye perspective of the general principles of stem-cell therapy and tissue engineering; it relates comparative knowledge in this area to the current and future status of equine regenerative medicine.The understanding of equine stem cell biology, biofactors, and scaffolds......, and their potential therapeutic use in horses are rudimentary at present. Mesenchymal stem cell isolation has been proclaimed from several equine tissues in the past few years. Based on the criteria of the International Society for Cellular Therapy, most of these cells are more correctly referred to as multipotent...

  17. Projection Stereolithographic Fabrication of Human Adipose Stem Cell-incorporated Biodegradable Scaffolds for Cartilage Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Aaron X Sun

    2015-08-01

    Full Text Available Poor self-healing ability of cartilage necessitates the development of methods for cartilage regeneration. Scaffold construction with live stem cell incorporation and subsequent differentiation presents a promising route. Projection stereolithography (PSL offers high resolution and processing speed as well as the ability to fabricate scaffolds that precisely fit the anatomy of cartilage defects using medical imaging as the design template. We report here the use of a visible-light based PSL (VL-PSL system to encapsulate human adipose-derived stem cells (hASCs into a biodegradable polymer (poly-D,L-lactic acid/polyethylene glycol/ poly-D,L-lactic acid (PDLLA-PEG/hyaluronic acid (HA matrix to produce live cell constructs with customized architectures. After fabrication, hASCs showed high viability (84% and were uniformly distributed throughout the constructs, which possessed high mechanical property with a compressive modulus of 780 kPa. The hASC-seeded constructs were then cultured in Control or TGF-β3-containing chondrogenic medium for up to 28 days. In chondrogenic medium treated group (TGF-β3 group hASCs maintained 77% viability and expressed chondrogenic genes Sox9, collagen type II, and aggrecan at 11, 232, and 2.29 x 10(5 fold increases, respectively, compared to levels at day 0 in non-chondrogenic medium. The TGF-β3 group also produced a collagen type II and glycosaminoglycan (GAG-rich extracellular matrix, detected by immunohistochemistry, and Alcian blue and Safranin O staining suggesting robust chondrogenesis within the scaffold. Without chondroinductive addition (Control group, cell viability decreased with time (65% at 28 days and showed poor cartilage matrix deposition. After 28 days, mechanical strength of the TGF-β3 group remained high at 240 kPa. Thus, the PSL- and PLLA-PEG/HA based fabrication method using adult stem cells is a promising approach in producing mechanically competent engineered cartilage for joint cartilage

  18. Stochastic signaling in biochemical cascades and genetic systems in genetically engineered living cells

    Science.gov (United States)

    Daniel, Ramiz; Almog, Ronen; Shacham-Diamand, Yosi

    2010-04-01

    Living cells, either prokaryote or eukaryote, can be integrated within whole-cell biochips (WCBCs) for various applications. We investigate WCBCs where information is extracted from the cells via a cascade of biochemical reactions that involve gene expression. The overall biological signal is weak due to small sample volume, low intrinsic cell response, and extrinsic signal loss mechanisms. The low signal-to-noise ratio problem is aggravated during initial detection stages and limits the minimum detectable signal or, alternatively, the minimum detection time. Taking into account the stochastic nature of biochemical process, we find that the signal is accompanied by relatively large noise disturbances. In this work, we use genetically engineered microbe sensors as a model to study the biochips output signal stochastic behavior. In our model, the microbes are designed to express detectable reporter proteins under external induction. We present analytical approximated expressions and numerical simulations evaluating the fluctuations of the synthesized reporter proteins population based on a set of equations modeling a cascade of biochemical and genetic reactions. We assume that the reporter proteins decay more slowly than messenger RNA molecules. We calculate the relation between the noise of the input signal (extrinsic noise) and biochemical reaction statistics (intrinsic noise). We discuss in further details two cases: (1) a cascade with large decay rates of all biochemical reactions compared to the protein decay rate. We show that in this case, the noise amplitude has a positive linear correlation with the number of stages in the cascade. (2) A cascade which includes a stable enzymatic-binding reaction with slow decay rate. We show that in this case, the noise strongly depends on the protein decay rate. Finally, a general observation is presented stating that the noise in whole-cell biochip sensors is determined mainly by the first reactions in the genetic system

  19. Boron nitride nanotube-mediated stimulation of cell co-culture on micro-engineered hydrogels.

    Directory of Open Access Journals (Sweden)

    Leonardo Ricotti

    Full Text Available In this paper, we describe the effects of the combination of topographical, mechanical, chemical and intracellular electrical stimuli on a co-culture of fibroblasts and skeletal muscle cells. The co-culture was anisotropically grown onto an engineered micro-grooved (10 µm-wide grooves polyacrylamide substrate, showing a precisely tuned Young's modulus (∼ 14 kPa and a small thickness (∼ 12 µm. We enhanced the co-culture properties through intracellular stimulation produced by piezoelectric nanostructures (i.e., boron nitride nanotubes activated by ultrasounds, thus exploiting the ability of boron nitride nanotubes to convert outer mechanical waves (such as ultrasounds in intracellular electrical stimuli, by exploiting the direct piezoelectric effect. We demonstrated that nanotubes were internalized by muscle cells and localized in both early and late endosomes, while they were not internalized by the underneath fibroblast layer. Muscle cell differentiation benefited from the synergic combination of topographical, mechanical, chemical and nanoparticle-based stimuli, showing good myotube development and alignment towards a preferential direction, as well as high expression of genes encoding key proteins for muscle contraction (i.e., actin and myosin. We also clarified the possible role of fibroblasts in this process, highlighting their response to the above mentioned physical stimuli in terms of gene expression and cytokine production. Finally, calcium imaging-based experiments demonstrated a higher functionality of the stimulated co-cultures.

  20. Use of Adult Stem Cells for Cartilage Tissue Engineering: Current Status and Future Developments

    Directory of Open Access Journals (Sweden)

    Catherine Baugé

    2015-01-01

    Full Text Available Due to their low self-repair ability, cartilage defects that result from joint injury, aging, or osteoarthritis, are the most often irreversible and are a major cause of joint pain and chronic disability. So, in recent years, researchers and surgeons have been working hard to elaborate cartilage repair interventions for patients who suffer from cartilage damage. However, current methods do not perfectly restore hyaline cartilage and may lead to the apparition of fibro- or hypertrophic cartilage. In the next years, the development of new strategies using adult stem cells, in scaffolds, with supplementation of culture medium and/or culture in low oxygen tension should improve the quality of neoformed cartilage. Through these solutions, some of the latest technologies start to bring very promising results in repairing cartilage from traumatic injury or chondropathies. This review discusses the current knowledge about the use of adult stem cells in the context of cartilage tissue engineering and presents clinical trials in progress, as well as in the future, especially in the field of bioprinting stem cells.

  1. Ambient Engineering for High-Performance Organic-Inorganic Perovskite Hybrid Solar Cells.

    Science.gov (United States)

    Huang, Jiabin; Yu, Xuegong; Xie, Jiangsheng; Xu, Dikai; Tang, Zeguo; Cui, Can; Yang, Deren

    2016-08-24

    Considering the evaporation of solvents during fabrication of perovskite films, the organic ambience will present a significant influence on the morphologies and properties of perovskite films. To clarify this issue, various ambiences of N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and chlorobenzene (CBZ) are introduced during fabrication of perovskite films by two-step sequential deposition method. The results reveal that an ambient CBZ atmosphere is favorable to control the nucleation and growth of CH3NH3PbI3 grains while the others present a negative effect. The statistical results show that the average efficiencies of perovskite solar cells processed in an ambient CBZ atmosphere can be significantly improved by a relatively average value of 35%, compared with those processed under air. The efficiency of the best perovskite solar cells can be improved from 10.65% to 14.55% by introducing this ambience engineering technology. The CH3NH3PbI3 film with large-size grains produced in an ambient CBZ atmosphere can effectively reduce the density of grain boundaries, and then the recombination centers for photoinduced carriers. Therefore, a higher short-circuit current density is achieved, which makes main contribution to the improvement in efficiency. These results provide vital progress toward understanding the role of ambience in the realization of highly efficient perovskite solar cells. PMID:27489961

  2. Engineering a 70-percent efficient, indirect-fired fuel-cell bottomed turbine cycle

    Energy Technology Data Exchange (ETDEWEB)

    Williams, M.C.; Micheli, P.L.; Parson, E.L. Jr. [Dept. of Energy, Morgantown, WV (United States)

    1995-08-01

    We introduce the natural gas, indirect-fired fuel-cell bottomed turbine cycle (NG-IFFC) as a novel power plant system for the distributed power and on-site markets in the 20 to 200 megawatt (MW) size range. The NG-IFFC system is a new METC-patented system. This power-plant system links the ambient pressure, carbonate fuel cell in tandem with a gas turbine, air compressor, combustor, and ceramic heat exchanger. Performance calculations based on Advanced System for Process Engineering (ASPEN) simulations show material and energy balances with expected power output. Early results indicated efficiencies and heat rates for the NG-EFFC are comparable to conventionally bottomed, carbonate fuel-cell steam-bottomed cycles, but with smaller and less expensive components. More recent calculations extended the in-tandem concept to produce near-stoichiometric usage of the oxygen. This is made possible by reforming the anode stream to completion and using all hydrogen fuel in what will need to be a special combustor. The performance increases dramatically to greater than 70 percent.

  3. Engineering nanoparticles surface for biosensing: "Chemical noses" to detect and identify proteins, bacteria and cancerous cells

    Science.gov (United States)

    Miranda-Sanchez, Oscar Ramon

    Rapid and sensitive detection of biomolecules is an important issue in nanomedicine. Many disorders are manifested by changes in protein levels of serum and other biofluids. Rapid and effective differentiation between normal and cancerous cells is an important challenge for the diagnosis and treatment of tumor. Likewise, rapid and effective identification of pathogens is a key target in both biomedical and environmental monitoring. Most biological recognition processes occur via specific interactions. Gold nanoparticles (AuNP s) feature sizes commensurate with biomacromolecules, coupled with useful physical and optical properties. A key issue in the use of nanomaterials is controlling the interfacial interactions of these complex systems. Modulation of these physicochemical properties can be readily achieved by engineering nanoparticles surface. Inspired by the idea of mimicking nature, a convenient, precise and rapid method for sensing proteins, cancerous cells and bacteria has been developed by overtaking the superb performance of biological olfactory systems in odor detection, identification, tracking, and location. On the fundamental side, an array-based/'chemical nose' sensor composed of cationic functionalized AuNPs as receptors and anionic fluorescent conjugated polymers or green fluorescent proteins or enzyme/substrates as transducers that can properly detect and identify proteins, bacteria, and cancerous cells has been successfully fabricated.

  4. Proton Exchange Membrane Fuel Cell Engineering Model Powerplant. Test Report: Benchmark Tests in Three Spatial Orientations

    Science.gov (United States)

    Loyselle, Patricia; Prokopius, Kevin

    2011-01-01

    Proton exchange membrane (PEM) fuel cell technology is the leading candidate to replace the aging alkaline fuel cell technology, currently used on the Shuttle, for future space missions. This test effort marks the final phase of a 5-yr development program that began under the Second Generation Reusable Launch Vehicle (RLV) Program, transitioned into the Next Generation Launch Technologies (NGLT) Program, and continued under Constellation Systems in the Exploration Technology Development Program. Initially, the engineering model (EM) powerplant was evaluated with respect to its performance as compared to acceptance tests carried out at the manufacturer. This was to determine the sensitivity of the powerplant performance to changes in test environment. In addition, a series of tests were performed with the powerplant in the original standard orientation. This report details the continuing EM benchmark test results in three spatial orientations as well as extended duration testing in the mission profile test. The results from these tests verify the applicability of PEM fuel cells for future NASA missions. The specifics of these different tests are described in the following sections.

  5. Implantable tissue-engineered blood vessels from human induced pluripotent stem cells.

    Science.gov (United States)

    Gui, Liqiong; Dash, Biraja C; Luo, Jiesi; Qin, Lingfeng; Zhao, Liping; Yamamoto, Kota; Hashimoto, Takuya; Wu, Hongwei; Dardik, Alan; Tellides, George; Niklason, Laura E; Qyang, Yibing

    2016-09-01

    Derivation of functional vascular smooth muscle cells (VSMCs) from human induced pluripotent stem cells (hiPSCs) to generate tissue-engineered blood vessels (TEBVs) holds great potential in treating patients with vascular diseases. Herein, hiPSCs were differentiated into alpha-smooth muscle actin (α-SMA) and calponin-positive VSMCs, which were seeded onto polymer scaffolds in bioreactors for vascular tissue growth. A functional TEBV with abundant collagenous matrix and sound mechanics resulted, which contained cells largely positive for α-SMA and smooth muscle myosin heavy chain (SM-MHC). Moreover, when hiPSC-derived TEBV segments were implanted into nude rats as abdominal aorta interposition grafts, they remained unruptured and patent with active vascular remodeling, and showed no evidence of teratoma formation during a 2-week proof-of-principle study. Our studies represent the development of the first implantable TEBVs based on hiPSCs, and pave the way for developing autologous or allogeneic grafts for clinical use in patients with vascular disease. PMID:27336184

  6. Bachelor of Science-Engineering Technology Program and Fuel Cell Education Program Concentration

    Energy Technology Data Exchange (ETDEWEB)

    Block, David L.; Sleiti, Ahmad

    2011-09-19

    The Hydrogen and Fuel Cell Technology education project has addressed DOE goals by supplying readily available, objective, technical, and accurate information that is available to students, industry and the public. In addition, the program has supplied educated trainers and training opportunities for the next generation workforce needed for research, development, and demonstration activities in government, industry, and academia. The project has successfully developed courses and associated laboratories, taught the new courses and labs and integrated the HFCT option into the accredited engineering technology and mechanical engineering programs at the University of North Carolina at Charlotte (UNCC). The project has also established ongoing collaborations with the UNCC energy related centers of the Energy Production & Infrastructure Center (EPIC), the NC Motorsports and Automotive Research Center (NCMARC) and the Infrastructure, Design, Environment and Sustainability Center (IDEAS). The results of the project activities are presented as two major areas – (1) course and laboratory development, offerings and delivery, and (2) program recruitment, promotions and collaborations. Over the project period, the primary activity has been the development and offering of 11 HFCT courses and accompanying laboratories. This process has taken three years with the courses first being developed and then offered each year over the timeframe.

  7. Complete biodegradation of chlorpyrifos by engineered Pseudomonas putida cells expressing surface-immobilized laccases.

    Science.gov (United States)

    Liu, Jin; Tan, Luming; Wang, Jing; Wang, Zhiyong; Ni, Hong; Li, Lin

    2016-08-01

    The long-term abuse use of chlorpyrifos-like pesticides in agriculture and horticulture has resulted in significant soil or water contamination and a worldwide ecosystem threat. In this study, the ability of a solvent-tolerant bacterium, Pseudomonas putida MB285, with surface-displayed bacterial laccase, to biodegrade chlorpyrifos was investigated. The results of compositional analyses of the degraded products demonstrate that the engineered MB285 was capable of completely eliminating chlorpyrifos via direct biodegradation, as determined by high-performance liquid chromatography and gas chromatography-mass spectrometry assays. Two intermediate metabolites, namely 3,5,6-trichloro-2-pyridinol (TCP) and diethyl phosphate, were temporarily detectable, verifying the joint and stepwise degradation of chlorpyrifos by surface laccases and certain cellular enzymes, whereas the purified free laccase incompletely degraded chlorpyrifos into TCP. The degradation reaction can be conducted over a wide range of pH values (2-7) and temperatures (5-55 °C) without the need for Cu(2+). Bioassays using Caenorhabditis elegans as an indicator organism demonstrated that the medium was completely detoxified of chlorpyrifos by degradation. Moreover, the engineered cells exhibited a high capacity of repeated degradation and good performance in continuous degradation cycles, as well as a high capacity to degrade real effluents containing chlorpyrifos. Therefore, the developed system exhibited a high degradation capacity and performance and constitutes an improved approach to address chlorpyrifos contamination in chlorpyrifos-remediation practice. PMID:27231878

  8. Development of a dose-controlled multiculture cell exposure chamber for efficient delivery of airborne and engineered nanoparticles

    International Nuclear Information System (INIS)

    In order to study the various health influencing parameters related to engineered nanoparticles as well as to soot emitted by Diesel engines, there is an urgent need for appropriate sampling devices and methods for cell exposure studies that simulate the respiratory system and facilitate associated biological and toxicological tests. The objective of the present work was the further advancement of a Multiculture Exposure Chamber (MEC) into a dose-controlled system for efficient delivery of nanoparticles to cells. It was validated with various types of nanoparticles (Diesel engine soot aggregates, engineered nanoparticles for various applications) and with state-of-the-art nanoparticle measurement instrumentation to assess the local deposition of nanoparticles on the cell cultures. The dose of nanoparticles to which cell cultures are being exposed was evaluated in the normal operation of the in vitro cell culture exposure chamber based on measurements of the size specific nanoparticle collection efficiency of a cell free device. The average efficiency in delivering nanoparticles in the MEC was approximately 82%. The nanoparticle deposition was demonstrated by Transmission Electron Microscopy (TEM). Analysis and design of the MEC employs Computational Fluid Dynamics (CFD) and true to geometry representations of nanoparticles with the aim to assess the uniformity of nanoparticle deposition among the culture wells. Final testing of the dose-controlled cell exposure system was performed by exposing A549 lung cell cultures to fluorescently labeled nanoparticles. Delivery of aerosolized nanoparticles was demonstrated by visualization of the nanoparticle fluorescence in the cell cultures following exposure. Also monitored was the potential of the aerosolized nanoparticles to generate reactive oxygen species (ROS) (e.g. free radicals and peroxides generation), thus expressing the oxidative stress of the cells which can cause extensive cellular damage or damage on DNA.

  9. Dynamic Characteristic of a Fuel Cell Micro-Grid Using an Engine Generator to Base Load Operation

    OpenAIRE

    OBARA, Shinya

    2008-01-01

    The dynamic of a micro-grid consisting of an engine generator and sixteen fuel cells was clarified by the transfer function model using actual data from power generators. The micro-grid was composed of a 3kW engine generator and 1kW fuel cells, and the dynamic characteristics of the grid were analyzed using the energy demand model in February of a cold region. Consequently, the settling time (Time taken to converge on +-5% of the limit of an output target) of a micro-grid is 15 seconds from 1...

  10. Guidelines for Standardized Testing of Broadband Seismometers and Accelerometers

    Science.gov (United States)

    Hutt, Charles R.; Evans, John R.; Followill, Fred; Nigbor, Robert L.; Wielandt, Erhard

    2010-01-01

    Testing and specification of seismic and earthquake-engineering sensors and recorders has been marked by significant variations in procedures and selected parameters. These variations cause difficulty in comparing such specifications and test results. In July 1989, and again in May 2005, the U.S. Geological Survey hosted international pub-lic/private workshops with the goal of defining widely accepted guidelines for the testing of seismological inertial sensors, seismometers, and accelerometers. The Proceedings of the 2005 workshop have been published and include as appendix 6 the report of the 1989 workshop. This document represents a collation and rationalization of a single set of formal guidelines for testing and specifying broadband seismometers and accelerometers.

  11. Cavity-Enhanced Room-Temperature Broadband Raman Memory

    Science.gov (United States)

    Saunders, D. J.; Munns, J. H. D.; Champion, T. F. M.; Qiu, C.; Kaczmarek, K. T.; Poem, E.; Ledingham, P. M.; Walmsley, I. A.; Nunn, J.

    2016-03-01

    Broadband quantum memories hold great promise as multiplexing elements in future photonic quantum information protocols. Alkali-vapor Raman memories combine high-bandwidth storage, on-demand readout, and operation at room temperature without collisional fluorescence noise. However, previous implementations have required large control pulse energies and have suffered from four-wave-mixing noise. Here, we present a Raman memory where the storage interaction is enhanced by a low-finesse birefringent cavity tuned into simultaneous resonance with the signal and control fields, dramatically reducing the energy required to drive the memory. By engineering antiresonance for the anti-Stokes field, we also suppress the four-wave-mixing noise and report the lowest unconditional noise floor yet achieved in a Raman-type warm vapor memory, (15 ±2 )×10-3 photons per pulse, with a total efficiency of (9.5 ±0.5 )%.

  12. Broadband ultrathin low-profile metamaterial microwave absorber

    Science.gov (United States)

    Sood, Deepak; Tripathi, Chandra Charu

    2016-04-01

    In this paper, a single-layer broadband low-profile ultrathin metamaterial microwave absorber is proposed for wide angle of incidence. The proposed absorber provides triple-band absorption under normal incidence of electromagnetic wave with two peaks lying in X-band and one in Ku-band. The unit cell is designed by using parametric optimization in such a way that the three peaks merge together to give broadband absorption. The absorber exhibits full width at half maxima bandwidth (FWHM) of 7.75 GHz from 7.55 to 15.30 GHz for wide angle of incidence up to 60° for both TE and TM polarizations. The mechanism of absorption of the absorber has been analyzed by field and surface current distributions. The proposed absorber has been fabricated and experimentally tested for different angles of incidence and polarization of the incident wave. The absorber is low profile with unit cell dimension of the order of 0.168 λ 0, and it is ultrathin with a thickness of ~ λ 0/17 at the center frequency of 11.43 GHz corresponding to the FWHM absorption bandwidth. This proposed absorber can be used for many potential applications such as stealth technology, cloaking and in antenna systems.

  13. Socio Technical Impact of Broadband Services in Baluchistan

    OpenAIRE

    Saira Ahthasham; Aftab Ahmed Shaikh; Muhammad Iqbal; Ahtsham Sajid; Amir Shahzad

    2012-01-01

    Broadband infrastructure is a key component of knowledge economy. Broadband service both on fixed and mobile networks are becoming an indicator of the knowledge economy. Globally it is viewed    that countries with developed broadband infrastructures are working more efficiently and effectively towards social and economic growth. To achieve worldwide broadband connectivity level Government of Pakistan and industry must play a combine role for the betterment and improvement of the said industr...

  14. Surface engineered antifouling optomagnetic SPIONs for bimodal targeted imaging of pancreatic cancer cells

    Directory of Open Access Journals (Sweden)

    Wang X

    2014-03-01

    Full Text Available Xiaohui Wang,1 Xiaohong Xing,1 Bingbo Zhang,1 Fengjun Liu,1 Yingsheng Cheng,2 Donglu Shi1,31Radiology Department of the Tenth People’s Hospital,The Institute for Biomedical Engineering and Nano Science, Tongji University School of Medicine, Shanghai, People’s Republic of China; 2Department of Radiology, Shanghai Sixth People’s Hospital, Shanghai Jiaotong University, Shanghai, People’s Republic of China; 3Materials Science and Engineering Program, Department of Mechanical and Materials Engineering, College of Engineering and Applied Science, University of Cincinnati, Cincinnati, OH, USAAbstract: Targeted imaging contrast agents for early pancreatic ductal adenocarcinoma diagnosis was developed using superparamagnetic iron oxide nanoparticles (SPIONs. For phase transfer of SPIONs, the hydrophobic SPIONs are first treated with tetrafluoroborate and then capped by bovine serum albumin (BSA via ligand exchange. It was experimentally found that nitrosyl tetrafluoroborate pretreatment and proper structures of molecules are essential to the effective surface functionalization of SPIONs. Nonspecific binding was found to be significantly reduced by BSA surface functionalized hydrophobic SPIONs (BSA·SPIONs. The BSA·SPIONs were monodispersed with an average size of approximately 18.0 nm and stable in a wide pH range and various ionic strengths even after 7 days of storage. The longitudinal and transverse proton relaxation rate (r1, r2 values of the BSA·SPIONs were determined to be 11.6 and 154.2 s-1 per mM of Fe3+ respectively. The r2/r1 ratio of 13.3 ensured its application as the T2-weighted magnetic resonance imaging contrast agents. When conjugated with near-infrared fluorescent dye and monoclonal antibody, the dyeBSA·SPION-monoclonal antibody bioconjugates showed excellent targeting capability with minimal nonspecific binding in the bimodal imaging of pancreatic cancer cells. The experimental approach is facile, environmentally benign, and

  15. Broadband diffuse terahertz wave scattering by flexible metasurface with randomized phase distribution

    OpenAIRE

    Yin Zhang; Lanju Liang; Jing Yang; Yijun Feng; Bo Zhu; Junming Zhao; Tian Jiang; Biaobing Jin; Weiwei Liu

    2016-01-01

    Suppressing specular electromagnetic wave reflection or backward radar cross section is important and of broad interests in practical electromagnetic engineering. Here, we present a scheme to achieve broadband backward scattering reduction through diffuse terahertz wave reflection by a flexible metasurface. The diffuse scattering of terahertz wave is caused by the randomized reflection phase distribution on the metasurface, which consists of meta-particles of differently sized metallic patche...

  16. Broadband anomalous reflection based on gradient low-Q meta-surface

    OpenAIRE

    Mingbo Pu; Po Chen; Changtao Wang; Yanqin Wang; Zeyu Zhao; Chenggang Hu; Cheng Huang; Xiangang Luo

    2013-01-01

    Gradient–index metamaterial is crucial in the spatial manipulation of electromagnetic wave. Here we present an efficient approach to extend the bandwidth of phase modulation by utilizing the broadband characteristic of low-quality (Q) meta-surface in the reflection mode. The dispersion of the meta-surface is engineered to compensate the phase difference induced by frequency change. Meanwhile, a thin gradient index cover layer is added on the top of meta-surface to extend the phase modulation ...

  17. Energy Supply Characteristics of a Combined Solar Cell and Diesel Engine System with a Prediction Algorithm for Solar Power Generation

    Science.gov (United States)

    El-Sayed, Abeer Galal; Obara, Shin'ya

    The production of electricity from the solar cells continues to attract interest as a power source for distributed energy generation. It is important to be able to estimate solar cell power to optimize system energy management. This paper proposes a prediction algorithm based on a neural network (NN) to predict the electricity production from a solar cell. The operation plan for a combined solar cell and diesel engine generator system is examined using the NN prediction algorithm. Two systems are examined in this paper: one with and one without a power storage facility. Comparisons are presented of the results from the two systems with respect to the actual calculations of output power and the predicted electricity production from the solar cell. The exhaust heat from the engine is used to supply the heat demand. A back-up boiler is operated when the engine exhaust heat is insufficient to meet the heat demand. Electricity and heat are supplied to the demand side from the proposed systems, and no external sources are used. When the NN production-of-electricity prediction was introduced, the engine generator operating time was reduced by 12.5% in December and 16.7% for March and September. Moreover, an operation plan for the combined system exhaust heat is proposed, and the heat output characteristics of the back-up boiler are characterized.

  18. Analysis and metabolic engineering of lipid-linked oligosaccharides in glycosylation-deficient CHO cells

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Meredith B., E-mail: mbauman7@jhu.edu [Department of Chemical and Biomolecular Engineering, Johns Hopkins University, 3400 North Charles Street, Maryland Hall 221, Baltimore, MD 21218 (United States); Tomiya, Noboru, E-mail: ntomiya1@jhu.edu [Department of Biology, Johns Hopkins University, 3400 North Charles Street, Mudd Hall 104A, Baltimore, MD 21218 (United States); Betenbaugh, Michael J., E-mail: beten@jhu.edu [Department of Chemical and Biomolecular Engineering, Johns Hopkins University, 3400 North Charles Street, Maryland Hall 221, Baltimore, MD 21218 (United States); Krag, Sharon S., E-mail: skrag@jhsph.edu [Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, 615 North Wolfe Street, Baltimore, MD 21205 (United States)

    2010-04-23

    Glycosylation-deficient Chinese Hamster Ovary (CHO) cell lines can be used to expand our understanding of N-glycosylation pathways and to study Congenital Disorders of Glycosylation, diseases caused by defects in the synthesis of N-glycans. The mammalian N-glycosylation pathway involves the step-wise assembly of sugars onto a dolichol phosphate (P-Dol) carrier, forming a lipid-linked oligosaccharide (LLO), followed by the transfer of the completed oligosaccharide onto the protein of interest. In order to better understand how deficiencies in this pathway affect the availability of the completed LLO donor for use in N-glycosylation, we used a non-radioactive, HPLC-based assay to examine the intermediates in the LLO synthesis pathway for CHO-K1 cells and for three different glycosylation-deficient CHO cell lines. B4-2-1 cells, which have a mutation in the dolichol phosphate-mannose synthase (DPM2) gene, accumulated LLO with the structure Man{sub 5}GlcNAc{sub 2}-P-P-Dol, while MI8-5 cells, which lack glucosyltransferase I (ALG6) activity, accumulated Man{sub 9}GlcNAc{sub 2}-P-P-Dol. CHO-K1 and MI5-4 cells both produced primarily the complete LLO, Glc{sub 3}Man{sub 9}GlcNAc{sub 2}-P-P-Dol, though the relative quantity was lower in MI5-4. MI5-4 cells have reduced hexokinase activity which could affect the availability of many of the substrates required for LLO synthesis and, consequently, impair production of the final LLO donor. Increasing hexokinase activity by overexpressing hexokinase II in MI5-4 caused a decrease in the relative quantities of the incomplete LLO intermediates from Man{sub 5}GlcNAc{sub 2}-PP-Dol through Glc{sub 1}Man{sub 9}GlcNAc{sub 2}-PP-Dol, and an increase in the relative quantity of the final LLO donor, Glc{sub 3}Man{sub 9}GlcNAc{sub 2}-P-P-Dol. This study suggests that metabolic engineering may be a useful strategy for improving LLO availability for use in N-glycosylation.

  19. Biomolecular interactions and responses of human epithelial and macrophage cells to engineered nanomaterials.

    Energy Technology Data Exchange (ETDEWEB)

    Kotula, Paul Gabriel; Brozik, Susan Marie; Achyuthan, Komandoor E.; Greene, Adrienne Celeste; Timlin, Jerilyn Ann; Bachand, George David; Bachand, Marlene; Aaron, Jesse S.; Allen, Amy; Seagrave, Jean-Clare

    2011-12-01

    Engineered nanomaterials (ENMs) are increasingly being used in commercial products, particularly in the biomedical, cosmetic, and clothing industries. For example, pants and shirts are routinely manufactured with silver nanoparticles to render them 'wrinkle-free.' Despite the growing applications, the associated environmental health and safety (EHS) impacts are completely unknown. The significance of this problem became pervasive within the general public when Prince Charles authored an article in 2004 warning of the potential social, ethical, health, and environmental issues connected to nanotechnology. The EHS concerns, however, continued to receive relatively little consideration from federal agencies as compared with large investments in basic nanoscience R&D. The mounting literature regarding the toxicology of ENMs (e.g., the ability of inhaled nanoparticles to cross the blood-brain barrier; Kwon et al., 2008, J. Occup. Health 50, 1) has spurred a recent realization within the NNI and other federal agencies that the EHS impacts related to nanotechnology must be addressed now. In our study we proposed to address critical aspects of this problem by developing primary correlations between nanoparticle properties and their effects on cell health and toxicity. A critical challenge embodied within this problem arises from the ability to synthesize nanoparticles with a wide array of physical properties (e.g., size, shape, composition, surface chemistry, etc.), which in turn creates an immense, multidimensional problem in assessing toxicological effects. In this work we first investigated varying sizes of quantum dots (Qdots) and their ability to cross cell membranes based on their aspect ratio utilizing hyperspectral confocal fluorescence microscopy. We then studied toxicity of epithelial cell lines that were exposed to different sized gold and silver nanoparticles using advanced imaging techniques, biochemical analyses, and optical and mass spectrometry

  20. Surface engineering and characterization of quantum dots and its application in living cell imaging

    Directory of Open Access Journals (Sweden)

    Han QIU

    2016-06-01

    Full Text Available Objective  Surface modification of hydrophobic nanoparticles is a key process for their application in the biological medicine fields. The aim of present study is to prepare the immunofluorescent probes by conjugation of hydrophilic surface-engineered quantum dots (QDs and monoclonal antibody for use of fluorescence labeled cells tracing. Methods  The bovine serum albumin (BSA with excellent water-solubility and biocompatibility was employed as the emulsifying agent, and used for surface modification of hydrophobic QDs under ultrasonication. The diameter, fluorescence spectrum and cytotoxicity of BSA-coated QDs (BSA-triP.QDs were analyzed. Then the BSA-coated QDs were conjugated with trastuzumab, which can be recognized and bound specifically to HER2. SKBR-3 breast cancer cells, with over-expression of HER-2, were labeled with hydrophilic QDstrastuzumab and imaged on a fluorescence planar imaging system. Results  The experimental results revealed that BSA as the emulsifying agent, combined with other polymers, can effectively phase transfer hydrophobic QDs. The BSA functionalized QDs exhibited excellent colloidal stability with fine hydrodynamic size distribution (about 70nm in a wide range of pH and ionic strengths values. Moreover, no significant cytotoxic effect was observed in SKBR-3 cells treated with BSA-coated QDs. After being coupled with trastuzumab, the hydrophilic QDs can be used as an immunofluorescence probe for HER2-positive breast cancer cell imaging. Conclusions  The advantages of BSA-coated QDs include straight forward synthesis, high colloidal stability, and promising immunofluorescence characteristic when coupled with specific antibody. These are therefore proved to be ideal nano systems for biomedical labeling, targeting, and imaging. DOI: 10.11855/j.issn.0577-7402.2016.05.04