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Sample records for cell selection devices

  1. Cell Selection Game for Densely-Deployed Sensor and Mobile Devices In 5G Networks Integrating Heterogeneous Cells and the Internet of Things

    Directory of Open Access Journals (Sweden)

    Lusheng Wang

    2015-09-01

    Full Text Available With the rapid development of wireless networking technologies, the Internet of Things and heterogeneous cellular networks (HCNs tend to be integrated to form a promising wireless network paradigm for 5G. Hyper-dense sensor and mobile devices will be deployed under the coverage of heterogeneous cells, so that each of them could freely select any available cell covering it and compete for resource with others selecting the same cell, forming a cell selection (CS game between these devices. Since different types of cells usually share the same portion of the spectrum, devices selecting overlapped cells can experience severe inter-cell interference (ICI. In this article, we study the CS game among a large amount of densely-deployed sensor and mobile devices for their uplink transmissions in a two-tier HCN. ICI is embedded with the traditional congestion game (TCG, forming a congestion game with ICI (CGI and a congestion game with capacity (CGC. For the three games above, we theoretically find the circular boundaries between the devices selecting the macrocell and those selecting the picocells, indicated by the pure strategy Nash equilibria (PSNE. Meanwhile, through a number of simulations with different picocell radii and different path loss exponents, the collapse of the PSNE impacted by severe ICI (i.e., a large number of picocell devices change their CS preferences to the macrocell is profoundly revealed, and the collapse points are identified.

  2. Cell Selection Game for Densely-Deployed Sensor and Mobile Devices In 5G Networks Integrating Heterogeneous Cells and the Internet of Things.

    Science.gov (United States)

    Wang, Lusheng; Wang, Yamei; Ding, Zhizhong; Wang, Xiumin

    2015-09-18

    With the rapid development of wireless networking technologies, the Internet of Things and heterogeneous cellular networks (HCNs) tend to be integrated to form a promising wireless network paradigm for 5G. Hyper-dense sensor and mobile devices will be deployed under the coverage of heterogeneous cells, so that each of them could freely select any available cell covering it and compete for resource with others selecting the same cell, forming a cell selection (CS) game between these devices. Since different types of cells usually share the same portion of the spectrum, devices selecting overlapped cells can experience severe inter-cell interference (ICI). In this article, we study the CS game among a large amount of densely-deployed sensor and mobile devices for their uplink transmissions in a two-tier HCN. ICI is embedded with the traditional congestion game (TCG), forming a congestion game with ICI (CGI) and a congestion game with capacity (CGC). For the three games above, we theoretically find the circular boundaries between the devices selecting the macrocell and those selecting the picocells, indicated by the pure strategy Nash equilibria (PSNE). Meanwhile, through a number of simulations with different picocell radii and different path loss exponents, the collapse of the PSNE impacted by severe ICI (i.e., a large number of picocell devices change their CS preferences to the macrocell) is profoundly revealed, and the collapse points are identified.

  3. Cell Selection Game for Densely-Deployed Sensor and Mobile Devices In 5G Networks Integrating Heterogeneous Cells and the Internet of Things

    Science.gov (United States)

    Wang, Lusheng; Wang, Yamei; Ding, Zhizhong; Wang, Xiumin

    2015-01-01

    With the rapid development of wireless networking technologies, the Internet of Things and heterogeneous cellular networks (HCNs) tend to be integrated to form a promising wireless network paradigm for 5G. Hyper-dense sensor and mobile devices will be deployed under the coverage of heterogeneous cells, so that each of them could freely select any available cell covering it and compete for resource with others selecting the same cell, forming a cell selection (CS) game between these devices. Since different types of cells usually share the same portion of the spectrum, devices selecting overlapped cells can experience severe inter-cell interference (ICI). In this article, we study the CS game among a large amount of densely-deployed sensor and mobile devices for their uplink transmissions in a two-tier HCN. ICI is embedded with the traditional congestion game (TCG), forming a congestion game with ICI (CGI) and a congestion game with capacity (CGC). For the three games above, we theoretically find the circular boundaries between the devices selecting the macrocell and those selecting the picocells, indicated by the pure strategy Nash equilibria (PSNE). Meanwhile, through a number of simulations with different picocell radii and different path loss exponents, the collapse of the PSNE impacted by severe ICI (i.e., a large number of picocell devices change their CS preferences to the macrocell) is profoundly revealed, and the collapse points are identified. PMID:26393617

  4. Strategies for increasing the efficiency of heterojunction organic solar cells: material selection and device architecture.

    Science.gov (United States)

    Heremans, Paul; Cheyns, David; Rand, Barry P

    2009-11-17

    Thin-film blends or bilayers of donor- and acceptor-type organic semiconductors form the core of heterojunction organic photovoltaic cells. Researchers measure the quality of photovoltaic cells based on their power conversion efficiency, the ratio of the electrical power that can be generated versus the power of incident solar radiation. The efficiency of organic solar cells has increased steadily in the last decade, currently reaching up to 6%. Understanding and combating the various loss mechanisms that occur in processes from optical excitation to charge collection should lead to efficiencies on the order of 10% in the near future. In organic heterojunction solar cells, the generation of photocurrent is a cascade of four steps: generation of excitons (electrically neutral bound electron-hole pairs) by photon absorption, diffusion of excitons to the heterojunction, dissociation of the excitons into free charge carriers, and transport of these carriers to the contacts. In this Account, we review our recent contributions to the understanding of the mechanisms that govern these steps. Starting from archetype donor-acceptor systems of planar small-molecule heterojunctions and solution-processed bulk heterojunctions, we outline our search for alternative materials and device architectures. We show that non-planar phthalocynanines have appealing absorption characteristics but also have reduced charge carrier transport. As a result, the donor layer needs to be ultrathin, and all layers of the device have to be tuned to account for optical interference effects. Using these optimization techniques, we illustrate cells with 3.1% efficiency for the non-planar chloroboron subphthalocyanine donor. Molecules offering a better compromise between absorption and carrier mobility should allow for further improvements. We also propose a method for increasing the exciton diffusion length by converting singlet excitons into long-lived triplets. By doping a polymer with a

  5. Dual-patterned immunofiltration (DIF) device for the rapid efficient negative selection of heterogeneous circulating tumor cells.

    Science.gov (United States)

    Bu, Jiyoon; Kang, Yoon-Tae; Kim, Young Jun; Cho, Young-Ho; Chang, Hee Jin; Kim, Hojoong; Moon, Byung-In; Kim, Ho Gak

    2016-11-29

    The analysis of circulating tumor cells (CTCs) is an emerging field for estimating the metastatic relapse and tumor burden of cancer patients. However, the isolation of CTCs is still challenging due to their ambiguity, rarity, and heterogeneity. Here, we present an anti-CD45 antibody based dual-patterned immunofiltration (DIF) device for the enrichment of heterogeneous CTC subtypes by effective elimination of leukocytes. Our uniquely designed dual-patterned layers significantly enhance the binding chance between immuno-patterns and leukocytes due to the fluidic whirling and the increased binding sites, thus achieving superior negative selection in terms of high-throughput and high purity. From the experiments using lung cancer cells, 97.07 ± 2.79% of leukocytes were eliminated with less than 10% loss of cancerous cells at the flow rate of 1 mL h -1 . To verify the device as a potential diagnostic tool, CTCs were collected from 11 cancer patients' blood and an average of 283.3 CTC-like cells were identified while less than 1 CTC-like cells were found from healthy donors. The samples were also analyzed by immunohistochemistry and the reverse transcription polymerase chain reaction to identify their heterogeneous characteristics. These remarkable results demonstrate that the present device could help to understand the unknown properties or undiscovered roles of CTCs with a non-biased view.

  6. Selection of Air Terminal Device

    DEFF Research Database (Denmark)

    Nielsen, Peter V.

    This paper discusses the selection of the air terminal device for the experiments and numerical prediction in the International Energy Agency Annex 20 work: Air Flow Pattern within Buildings,......This paper discusses the selection of the air terminal device for the experiments and numerical prediction in the International Energy Agency Annex 20 work: Air Flow Pattern within Buildings,...

  7. Selective shielding device for scintiphotography

    International Nuclear Information System (INIS)

    Harper, J.W.; Kay, T.D.

    1976-01-01

    A selective shielding device to be used in combination with a scintillation camera is described. The shielding device is a substantially oval-shaped configuration removably secured to the scintillation camera. As a result of this combination scanning of preselected areas of a patient can be rapidly and accurately performed without the requirement of mounting any type of shielding paraphernalia on the patient. 1 claim, 2 drawing figures

  8. Microfluidic Cell Culture Device

    Science.gov (United States)

    Takayama, Shuichi (Inventor); Cabrera, Lourdes Marcella (Inventor); Heo, Yun Seok (Inventor); Smith, Gary Daniel (Inventor)

    2014-01-01

    Microfluidic devices for cell culturing and methods for using the same are disclosed. One device includes a substrate and membrane. The substrate includes a reservoir in fluid communication with a passage. A bio-compatible fluid may be added to the reservoir and passage. The reservoir is configured to receive and retain at least a portion of a cell mass. The membrane acts as a barrier to evaporation of the bio-compatible fluid from the passage. A cover fluid may be added to cover the bio-compatible fluid to prevent evaporation of the bio-compatible fluid.

  9. A multi-channel device for high-density target-selective stimulation and long-term monitoring of cells and subcellular features in C. elegans

    Science.gov (United States)

    Coakley, Sean; Mugno, Paula; Hammarlund, Marc; Hilliard, Massimo A.; Lu, Hang

    2014-01-01

    Selective cell ablation can be used to identify neuronal functions in multicellular model organisms such as Caenorhabditis elegans. The optogenetic tool KillerRed facilitates selective ablation by enabling light-activated damage of cell or subcellular components in a temporally and spatially precise manner. However, the use of KillerRed requires stimulating (5 min-1 hr), culturing (~24 hrs) and imaging (often repeatedly) a large number of individual animals. Current manual manipulation methods are limited by their time-consuming, labor-intensive nature, and their usage of anesthetics. To facilitate large-scale selective ablation, culturing, and repetitive imaging, we developed a densely-packed multi-channel device and used it to perform high-throughput neuronal ablation on KillerRed-expressing animals. The ability to load worms in identical locations with high loading efficiency allows us to ablate selected neurons in multiple worms simultaneously. Our device also enables continuous observation of aminals for 24 hrs following KillerRed activation, and allows the animals to be recovered for behavioural assays. We expect this multi-channel device to facilitate a broad range of long-term imaging and selective illumination experiments in neuroscience. PMID:25257026

  10. Fluorescent switch for fast and selective detection of mercury (II) ions in vitro and in living cells and a simple device for its removal.

    Science.gov (United States)

    Yuan, Yue; Jiang, Shenlong; Miao, Qingqing; Zhang, Jia; Wang, Mengjing; An, Linna; Cao, Qinjingwen; Guan, Yafeng; Zhang, Qun; Liang, Gaolin

    2014-07-01

    A water-soluble, biocompatible, and fluorescent chemosensor (1) for label-free, simple, and fast detection of mercury ions (Hg(2+)) in aqueous solutions and in HepG2 cells with high selectivity is reported herein. Chelation of 1 with Hg(2+) results in the disappearance of its fluorescence emission at 350 nm and the appearance of a new emission at 405 nm. Selectivity and interference studies indicated that 1 could be selectively chelated by Hg(2+) without interference from other metal ions. Insight into the mechanisms responsible for its fluorescence effect was gained from ultrafast transient absorption spectroscopy. With these properties, 1 was successfully applied for imaging Hg(2+) in living cells and for removing Hg(2+) from river water. Moreover, we also constructed a simple device for fast and effective removal of Hg(2+) from contaminated liquid samples. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Variable wavelength selection devices: Physics and applications

    Science.gov (United States)

    Xianyu, Haiqing

    Variable wavelength selection (VWS) achieved by implementing tunability to wavelength discriminating devices has generated great interest in basic science, applied physics, and technology. This thesis focuses on the underlying physics and application of several novel wavelength discriminating devices. Holographical polymer dispersed liquid crystals (HPDLCs) are switchable volume gratings formed by exposing a photopolymerizable monomer and liquid crystal mixture to interfering monochromatic light beams. An HPDLCs wavelength discriminating ability along with its switchability, allow it to be utilized in VWS devices. A novel mode HPDLC, total internal reflection (TIR) HPDLC, has been developed as a wavelength selective filter. The grating planes in this device are tilted so that the diffracted light experiences total internal reflection at the glass-air interface and is trapped in the cell until it eventually escapes from an edge. A VWS device is demonstrated by stacking TIR HPDLCs operating at different wavelengths. Converging or diverging recording beams are employed to fabricate chirped reflection HPDLCs with a pitch gradient along the designated direction, creating chirped switchable reflection gratings (CSRGs). A pixelated version of the CSRG is developed herein, and a dynamic spectral equalizer is presented by combining the pixelated CSRG with a prism (for wavelength discrimination). A switchable circular to point converter (SCPC), which enables the random selection of the wavelength bands divided by the Fabry-Perot interferometer utilizing the controllable beam steering capability of transmission HPDLCs, is demonstrated. A random optical cross-switch (TIROL) can be created by integrating a Fabry-Perot interferometer with a stack of SCPC units. The in-plane electric field generated by the interdigitated electrodes is utilized to elongate the helical pitch of a cholesteric liquid crystal and thereby induces a red shift of the transmission reflection peak

  12. Control rod selecting and driving device

    International Nuclear Information System (INIS)

    Isobe, Hideo.

    1981-01-01

    Purpose: To simultaneously drive a predetermined number of control rods in a predetermined mode by the control of addresses for predetermined number of control rods and read or write of driving codified data to and from the memory by way of a memory controller. Constitution: The system comprises a control rod information selection device for selecting predetermined control rods from a plurality of control rods disposed in a reactor and outputting information for driving them in a predetermined mode, a control rod information output device for codifying the information outputted from the above device and outputting the addresses to the predetermined control rods and driving mode coded data, and a driving device for driving said predetermined control rods in a predetermined mode in accordance with the codified data outputted from the above device, said control rod infromation output device comprising a memory device capable of storing a predetermined number of the codified data and a memory control device for storing the predetermined number of data into the above memory device at a predetermined timing while successively outputting the thus stored predetermined number of data at a predetermined timing. (Seki, T.)

  13. Assembly For Moving a Robotic Device Along Selected Axes

    Science.gov (United States)

    Nowlin, Brentley Craig (Inventor); Koch, Lisa Danielle (Inventor)

    2001-01-01

    An assembly for moving a robotic device along selected axes includes a programmable logic controller (PLC) for controlling movement of the device along selected axes to effect movement of the device to a selected disposition. The PLC includes a plurality of single axis motion control modules, and a central processing unit (CPU) in communication with the motion control modules. A human-machine interface is provided for operator selection of configurations of device movements and is in communication with the CPU. A motor drive is in communication with each of the motion control modules and is operable to effect movement of the device along the selected axes to obtain movement of the device to the selected disposition.

  14. INVESTIGATION ON NORTH AMERICAN TRAFFIC CALMING DEVICE SELECTION PRACTICES

    Directory of Open Access Journals (Sweden)

    Farzana RAHMAN

    2009-01-01

    Full Text Available Traffic calming provides a process for identifying and addressing existing problems related to speeding, excessive traffic volume, and pedestrian safety concerns on residential streets. Although several traffic calming devices have been installed in Asian countries for example in Japan and Korea; they have no distinct and methodical process for the device selection. The objective of this research is to illustrate a comprehensive review of North American traffic calming device selection process practices. The aim is to establish traffic calming device selection process guiding principles to be introduced in Japan. This research reveals that speeding is the most significant issue for installing a traffic calming device. The result explores that community support is the most important factor for the selection of a traffic calming device. The result shows that speed humps and speed tables or raised crosswalks are the most widely practiced devices.

  15. Selective covers for natural cooling devices

    International Nuclear Information System (INIS)

    Addeo, A.; Monza, E.; Peraldo, M.; Bartoli, B.; Coluzzi, B.; Silvestrini, V.; Troise, G.

    1978-01-01

    Extra-atmospheric space is practically a pure sink of radiation, and can be used as a nonconventional energy source. In previous papers it has been shown that surfaces with an emissivity matched with the atmospheric (8/13)μm ''transparency window'' (natural emitters) interact with cold space when exposed to clear sky at night, and undergo a sizable cooling effect. In this paper, starting from experimental results concerning the diurnal performances of natural emitters, the problem of their interaction with solar radiation is discussed, and the use is proposed of selective covers which shade the emitter from solar radiation, without preventing the interaction with cold space via emission of infra-red radiation. (author)

  16. Probing cell mechanical properties with microfluidic devices

    Science.gov (United States)

    Rowat, Amy

    2012-02-01

    Exploiting flow on the micron-scale is emerging as a method to probe cell mechanical properties with 10-1000x advances in throughput over existing technologies. The mechanical properties of cells and the cell nucleus are implicated in a wide range of biological contexts: for example, the ability of white blood cells to deform is central to immune response; and malignant cells show decreased stiffness compared to benign cells. We recently developed a microfluidic device to probe cell and nucleus mechanical properties: cells are forced to deform through a narrow constrictions in response to an applied pressure; flowing cells through a series of constrictions enables us to probe the ability of hundreds of cells to deform and relax during flow. By tuning the constriction width so it is narrower than the width of the cell nucleus, we can specifically probe the effects of nuclear physical properties on whole cell deformability. We show that the nucleus is the rate-limiting step in cell passage: inducing a change in its shape to a multilobed structure results in cells that transit more quickly; increased levels of lamin A, a nuclear protein that is key for nuclear shape and mechanical stability, impairs the passage of cells through constrictions. We are currently developing a new class of microfluidic devices to simultaneously probe the deformability of hundreds of cell samples in parallel. Using the same soft lithography techniques, membranes are fabricated to have well-defined pore distribution, width, length, and tortuosity. We design the membranes to interface with a multiwell plate, enabling simultaneous measurement of hundreds of different samples. Given the wide spectrum of diseases where altered cell and nucleus mechanical properties are implicated, such a platform has great potential, for example, to screen cells based on their mechanical phenotype against a library of drugs.

  17. Integrated photonic devices by selective-area MOCVD

    Science.gov (United States)

    Osowski, Mark L.; Coleman, James J.

    1997-12-01

    Progress towards integrated photonic devices by three-step selective-area MOCVD is reviewed. Using the selective growth process, the quantum well thickness and, hence, the emission wavelength of buried heterostructure devices can be defined anywhere on a wafer surface by using an appropriate mask geometry for the active region regrowth. This in-plane bandgap energy control allows the designer to fabricate devices with different wavelengths on the same wafer for integrated photonic applications. Since no growth occurs on the oxide mask, the spacing between stripes defines the width of the lateral waveguide, and the width of the stripes defines the amount of growth rate and composition enhancement in the quantum well. As a result, a very wide range of emission wavelengths (960 - 1060 nm) can be obtained over the wafer surface in a single growth. This paper reviews a few of the high performance photonic devices fabricated using this method.

  18. Acoustofluidic devices controlled by cell phones.

    Science.gov (United States)

    Bachman, Hunter; Huang, Po-Hsun; Zhao, Shuaiguo; Yang, Shujie; Zhang, Peiran; Fu, Hai; Huang, Tony Jun

    2018-01-30

    Acoustofluidic devices have continuously demonstrated their potential to impact medical diagnostics and lab-on-a-chip applications. To bring these technologies to real-world applications, they must be made more accessible to end users. Herein, we report on the effort to provide an easy-to-use and portable system for controlling sharp-edge-based acoustofluidic devices. With the use of a cell phone and a modified Bluetooth® speaker, on-demand and hands-free pumping and mixing are achieved. Additionally, a novel design for a sharp-edge-based acoustofluidic device is proposed that combines both pumping and mixing functions into a single device, thus removing the need for external equipment typically needed to accomplish these two tasks. These applications serve to demonstrate the potential function that acoustofluidic devices can provide in point-of-care platforms. To further this point-of-care goal, we also design a portable microscope that combines with the cell phone and Bluetooth® power supply, providing a completely transportable acoustofluidic testing station. This work serves to bolster the promising position that acoustofluidic devices have within the rapidly changing research and diagnostics fields.

  19. Modelling Technical and Economic Parameters in Selection of Manufacturing Devices

    Directory of Open Access Journals (Sweden)

    Naqib Daneshjo

    2017-11-01

    Full Text Available Sustainable science and technology development is also conditioned by continuous development of means of production which have a key role in structure of each production system. Mechanical nature of the means of production is complemented by controlling and electronic devices in context of intelligent industry. A selection of production machines for a technological process or technological project has so far been practically resolved, often only intuitively. With regard to increasing intelligence, the number of variable parameters that have to be considered when choosing a production device is also increasing. It is necessary to use computing techniques and decision making methods according to heuristic methods and more precise methodological procedures during the selection. The authors present an innovative model for optimization of technical and economic parameters in the selection of manufacturing devices for industry 4.0.

  20. Selectively-etched nanochannel electrophoretic and electrochemical devices

    Science.gov (United States)

    Surh, Michael P [Livermore, CA; Wilson, William D [Pleasanton, CA; Barbee, Jr., Troy W.; Lane, Stephen M [Oakland, CA

    2006-06-27

    Nanochannel electrophoretic and electrochemical devices having selectively-etched nanolaminates located in the fluid transport channel. The normally flat surfaces of the nanolaminate having exposed conductive (metal) stripes are selectively-etched to form trenches and baffles. The modifications of the prior utilized flat exposed surfaces increase the amount of exposed metal to facilitate electrochemical redox reaction or control the exposure of the metal surfaces to analytes of large size. These etched areas variously increase the sensitivity of electrochemical detection devices to low concentrations of analyte, improve the plug flow characteristic of the channel, and allow additional discrimination of the colloidal particles during cyclic voltammetry.

  1. The Steerable Microcatheter: A New Device for Selective Catheterisation

    Energy Technology Data Exchange (ETDEWEB)

    Soyama, Takeshi [Hokkaido University Hospital, Department of Diagnostic and Interventional Radiology (Japan); Yoshida, Daisuke [Sapporo Yamanoue Hospital, Department of Radiology (Japan); Sakuhara, Yusuke, E-mail: yusaku@med.hokudai.ac.jp; Morita, Ryo; Abo, Daisuke; Kudo, Kohsuke [Hokkaido University Hospital, Department of Diagnostic and Interventional Radiology (Japan)

    2017-06-15

    The steerable microcatheter (SwiftNINJA, Sumitomo Bakelite, Tokyo, Japan), which has a remote-controlled flexible tip manipulated using a dial in the handgrip, was recently developed and delivered to the market. This device enables the user to change the angle of the microcatheter tip manually, and potentially makes selective catheterisation easier. We evaluated its unique characteristics and utility in selective catheterisation and coil embolization. This article describes: (1) the advantages of this device in catheterisations involving acute angle branches, and (2) a new technique of compact coil packing with the use of intentional folding by the bendable tip of the catheter.

  2. The Steerable Microcatheter: A New Device for Selective Catheterisation

    International Nuclear Information System (INIS)

    Soyama, Takeshi; Yoshida, Daisuke; Sakuhara, Yusuke; Morita, Ryo; Abo, Daisuke; Kudo, Kohsuke

    2017-01-01

    The steerable microcatheter (SwiftNINJA, Sumitomo Bakelite, Tokyo, Japan), which has a remote-controlled flexible tip manipulated using a dial in the handgrip, was recently developed and delivered to the market. This device enables the user to change the angle of the microcatheter tip manually, and potentially makes selective catheterisation easier. We evaluated its unique characteristics and utility in selective catheterisation and coil embolization. This article describes: (1) the advantages of this device in catheterisations involving acute angle branches, and (2) a new technique of compact coil packing with the use of intentional folding by the bendable tip of the catheter.

  3. Novel Hydrogen Purification Device Integrated with PEM Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    Joseph Schwartz; Hankwon Lim; Raymond Drnevich

    2010-12-31

    A prototype device containing twelve membrane tubes was designed, built, and demonstrated. The device produced almost 300 scfh of purified hydrogen at 200 psig feed pressure. The extent of purification met the program target of selectively removing enough impurities to enable industrial-grade hydrogen to meet purity specifications for PEM fuel cells. An extrusion process was developed to produce substrate tubes. Membranes met several test objectives, including completing 20 thermal cycles, exceeding 250 hours of operating life, and demonstrating a flux of 965 scfh/ft2 at 200 psid and 400 C.

  4. Cell biology apps for Apple devices.

    Science.gov (United States)

    Stark, Louisa A

    2012-01-01

    Apps for touch-pad devices hold promise for guiding and supporting learning. Students may use them in the classroom or on their own for didactic instruction, just-in-time learning, or review. Since Apple touch-pad devices (i.e., iPad and iPhone) have a substantial share of the touch-pad device market (Campbell, 2012), this Feature will explore cell biology apps available from the App Store. My review includes iPad and iPhone apps available in June 2012, but does not include courses, lectures, podcasts, audiobooks, texts, or other books. I rated each app on a five-point scale (1 star = lowest; 5 stars = highest) for educational and production values; I also provide an overall score.

  5. Polycaprolactone Thin-Film Micro- and Nanoporous Cell-Encapsulation Devices.

    Science.gov (United States)

    Nyitray, Crystal E; Chang, Ryan; Faleo, Gaetano; Lance, Kevin D; Bernards, Daniel A; Tang, Qizhi; Desai, Tejal A

    2015-06-23

    Cell-encapsulating devices can play an important role in advancing the types of tissue available for transplantation and further improving transplant success rates. To have an effective device, encapsulated cells must remain viable, respond to external stimulus, and be protected from immune responses, and the device itself must elicit a minimal foreign body response. To address these challenges, we developed a micro- and a nanoporous thin-film cell encapsulation device from polycaprolactone (PCL), a material previously used in FDA-approved biomedical devices. The thin-film device construct allows long-term bioluminescent transfer imaging, which can be used for monitoring cell viability and device tracking. The ability to tune the microporous and nanoporous membrane allows selective protection from immune cell invasion and cytokine-mediated cell death in vitro, all while maintaining typical cell function, as demonstrated by encapsulated cells' insulin production in response to glucose stimulation. To demonstrate the ability to track, visualize, and monitor the viability of cells encapsulated in implanted thin-film devices, we encapsulated and implanted luciferase-positive MIN6 cells in allogeneic mouse models for up to 90 days. Lack of foreign body response in combination with rapid neovascularization around the device shows promise in using this technology for cell encapsulation. These devices can help elucidate the metrics required for cell encapsulation success and direct future immune-isolation therapies.

  6. Selective laser etching or ablation for fabrication of devices

    KAUST Repository

    Buttner, Ulrich

    2017-01-12

    Methods of fabricating devices vial selective laser etching are provided. The methods can include selective laser etching of a portion of a metal layer, e.g. using a laser light source having a wavelength of 1,000 nm to 1,500 nm. The methods can be used to fabricate a variety of features, including an electrode, an interconnect, a channel, a reservoir, a contact hole, a trench, a pad, or a combination thereof. A variety of devices fabricated according to the methods are also provided. In some aspects, capacitive humidity sensors are provided that can be fabricated according to the provided methods. The capacitive humidity sensors can be fabricated with intricate electrodes, e.g. having a fractal pattern such as a Peano curve, a Hilbert curve, a Moore curve, or a combination thereof.

  7. Material and Device Stability in Perovskite Solar Cells.

    Science.gov (United States)

    Kim, Hui-Seon; Seo, Ja-Young; Park, Nam-Gyu

    2016-09-22

    Organic-inorganic halide perovskite solar cells have attracted great attention because of their superb efficiency reaching 22 % and low-cost, facile fabrication processing. Nevertheless, stability issues in perovskite solar cells seem to block further advancements toward commercialization. Thus, device stability is one of the important topics in perovskite solar cell research. In the beginning, the poor moisture resistivity of the perovskite layer was considered as a main problem that hindered further development of perovskite solar cells, which encouraged engineering of the perovskite or protection of the perovskite by a buffer layer. Soon after, other parameters affecting long-term stability were sequentially found and various attempts have been made to enhance intrinsic and extrinsic stability. Here we review the recent progresses addressing stability issues in perovskite solar cells. In this report, we investigated factors affecting stability from material and device points of view. To gain a better understanding of the stability of the bulk perovskite material, decomposition mechanisms were investigated in relation to moisture, photons, and heat. Stability of full device should also be carefully examined because its stability is dependent not only on bulk perovskite but also on the interfaces and selective contacts. In addition, ion migration and current-voltage hysteresis were found to be closely related to stability. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Optimization of spectrally selective Si/SiO2 based filters for thermophotovoltaic devices

    Science.gov (United States)

    Khosroshahi, Farhad Kazemi; Ertürk, Hakan; Pınar Mengüç, M.

    2017-08-01

    Design of a spectrally selective filter based on one-dimensional Si/SiO2 layers is considered for improved performance of thermo-photovoltaic devices. Spectrally selective filters transmit only the convertible radiation from the emitter as non-convertible radiation leads to a reduction in cell efficiency due to heating. The presented Si/SiO2 based filter concept reflects the major part of the undesired range back to the emitter to minimize energy required for the process and it is adaptable to different types of cells and emitters with different temperatures since its cut-off wavelength can be tuned. While this study mainly focuses on InGaSb based thermo-photovoltaic cell, Si, GaSb, and Ga0.78In0.22As0.19Sb0.81 based cells are also examined. Transmittance of the structure is predicted by rigorous coupled wave approach. Genetic algorithm, which is a global optimization method, is used to find the best possible filter structure by considering the overall efficiency as an objective function that is maximized. The simulations show that significant enhancement in the overall system and device efficiency is possible by using such filters with TPV devices. The methodology described in this paper allows for an improved filter design procedure for selected applications.

  9. Social-Aware Relay Selection for Cooperative Multicast Device-to-Device Communications

    Directory of Open Access Journals (Sweden)

    Francesco Chiti

    2017-12-01

    Full Text Available The increasing use of social networks such as Facebook, Twitter, and Instagram to share photos, video streaming, and music among friends has generated a huge increase in the amount of data traffic over wireless networks. This social behavior has triggered new communication paradigms such as device-to-device (D2D and relaying communication schemes, which are both considered as strong drivers for the next fifth-generation (5G cellular systems. Recently, the social-aware layer and its relationship to and influence on the physical communications layer have gained great attention as emerging focus points. We focus here on the case of relaying communications to pursue the multicast data dissemination to a group of users forming a social community through a relay node, according to the extension of the D2D mode to the case of device-to-many devices. Moreover, in our case, the source selects the device to act as the relay among different users of the multicast group by taking into account both the propagation link conditions and the relay social-trust level with the constraint of minimizing the end-to-end content delivery delay. An optimization procedure is also proposed in order to achieve the best performance. Finally, numerical results are provided to highlight the advantages of considering the impact of social level on the end-to-end delivery delay in the integrated social–physical network in comparison with the classical relay-assisted multicast communications for which the relay social-trust level is not considered.

  10. Differential Medical Aerosol Device and Interface Selection in Patients during Spontaneous, Conventional Mechanical and Noninvasive Ventilation.

    Science.gov (United States)

    Ari, Arzu; Fink, James B

    2016-04-01

    Many aerosol delivery devices are available on the market that have different features, characteristics, and operating requirements that need to be considered for the effective treatment of patients with pulmonary diseases. Device selection in aerosol medicine is largely patient dependent. Since there is no aerosol device that suits all patient populations, device selection and successful integration of the prescribed aerosol device to patients is essential. This article explores key issues in differential device selection in spontaneously breathing adults with or without artificial airways, as well as critically ill patients receiving invasive and noninvasive ventilation, with discussion of considerations for integration of aerosol devices to each of these patient populations.

  11. Hybrid Solar Cells: Materials, Interfaces, and Devices

    Science.gov (United States)

    Mariani, Giacomo; Wang, Yue; Kaner, Richard B.; Huffaker, Diana L.

    Photovoltaic technologies could play a pivotal role in tackling future fossil fuel energy shortages, while significantly reducing our carbon dioxide footprint. Crystalline silicon is pervasively used in single junction solar cells, taking up 80 % of the photovoltaic market. Semiconductor-based inorganic solar cells deliver relatively high conversion efficiencies at the price of high material and manufacturing costs. A great amount of research has been conducted to develop low-cost photovoltaic solutions by incorporating organic materials. Organic semiconductors are conjugated hydrocarbon-based materials that are advantageous because of their low material and processing costs and a nearly unlimited supply. Their mechanical flexibility and tunable electronic properties are among other attractions that their inorganic counterparts lack. Recently, collaborations in nanotechnology research have combined inorganic with organic semiconductors in a "hybrid" effort to provide high conversion efficiencies at low cost. Successful integration of these two classes of materials requires a profound understanding of the material properties and an exquisite control of the morphology, surface properties, ligands, and passivation techniques to ensure an optimal charge carrier generation across the hybrid device. In this chapter, we provide background information of this novel, emerging field, detailing the various approaches for obtaining inorganic nanostructures and organic polymers, introducing a multitude of methods for combining the two components to achieve the desired morphologies, and emphasizing the importance of surface manipulation. We highlight several studies that have fueled new directions for hybrid solar cell research, including approaches for maximizing efficiencies by controlling the morphologies of the inorganic component, and in situ molecular engineering via electrochemical polymerization of a polymer directly onto the inorganic nanowire surfaces. In the end, we

  12. Selecting Cells for Bioartificial Liver Devices and the Importance of a 3D Culture Environment: A Functional Comparison between the HepaRG and C3A Cell Lines

    NARCIS (Netherlands)

    van Wenum, Martien; Adam, Aziza A. A.; Hakvoort, Theodorus B. M.; Hendriks, Erik J.; Shevchenko, Valery; van Gulik, Thomas M.; Chamuleau, Robert A. F. M.; Hoekstra, Ruurdtje

    2016-01-01

    Recently, the first clinical trials on Bioartificial Livers (BALs) loaded with a proliferative human hepatocyte cell source have started. There are two cell lines that are currently in an advanced state of BAL development; HepaRG and HepG2/C3A. In this study we aimed to compare both cell lines on

  13. On-Demand Cell Internal Short Circuit Device

    Science.gov (United States)

    Darcy, Eric; Keyser, Matthew

    2014-01-01

    A device implantable in Li-ion cells that can generate a hard internal short circuit on-demand by exposing the cell to 60?C has been demonstrated to be valuable for expanding our understanding of cell responses. The device provides a negligible impact to cell performance and enables the instigation of the 4 general categories of cell internal shorts to determine relative severity and cell design susceptibility. Tests with a 18650 cell design indicates that the anode active material short to the aluminum cathode current collector tends to be more catastrophic than the 3 other types of internal shorts. Advanced safety features (such as shutdown separators) to prevent or mitigate the severity of cell internal shorts can be verified with this device. The hard short success rate achieved to date in 18650 cells is about 80%, which is sufficient for using these cells in battery assemblies for field-failure-relevant, cell-cell thermal runaway propagation verification tests

  14. Modeling Emerging Solar Cell Materials and Devices

    Science.gov (United States)

    Thongprong, Non

    Organic photovoltaics (OPVs) and perovskite solar cells are emerging classes of solar cell that are promising for clean energy alternatives to fossil fuels. Understanding fundamental physics of these materials is crucial for improving their energy conversion efficiencies and promoting them to practical applications. Current density-voltage (JV) curves; which are important indicators of OPV efficiency, have direct connections to many fundamental properties of solar cells. They can be described by the Shockley diode equation, resulting in fitting parameters; series and parallel resistance (Rs and Rp), diode saturation current ( J0) and ideality factor (n). However, the Shockley equation was developed specifically for inorganic p-n junction diodes, so it lacks physical meanings when it is applied to OPVs. Hence, the puRposes of this work are to understand the fundamental physics of OPVs and to develop new diode equations in the same form as the Shockley equation that are based on OPV physics. We develop a numerical drift-diffusion simulation model to study bilayer OPVs, which will be called the drift-diffusion for bilayer interface (DD-BI) model. The model solves Poisson, drift-diffusion and current-continuity equations self-consistently for charge densities and potential profiles of a bilayer device with an organic heterojunction interface described by the GWWF model. We also derive new diode equations that have JV curves consistent with the DD-BI model and thus will be called self-consistent diode (SCD) equations. Using the DD-BI and the SCD model allows us to understand working principles of bilayer OPVs and physical definitions of the Shockley parameters. Due to low carrier mobilities in OPVs, space charge accumulation is common especially near the interface and electrodes. Hence, quasi-Fermi levels (i.e. chemical potentials), which depend on charge densities, are modified around the interface, resulting in a splitting of quasi-Fermi levels that works as a driving

  15. Asymmetric power device rating selection for even temperature distribution in NPC inverter

    DEFF Research Database (Denmark)

    Choi, Uimin; Blaabjerg, Frede

    2017-01-01

    the power rating and lifetime of the NPC inverter are limited by the most stressed devices. In this paper, an asymmetric power device rating selection method for the NPC inverter is proposed in order to balance the lifetimes of the power devices. The thermal distribution of the power devices is analyzed...

  16. A Model for Service Life Control of Selected Device Systems

    Directory of Open Access Journals (Sweden)

    Zieja Mariusz

    2014-04-01

    Full Text Available This paper presents a way of determining distribution of limit state exceedence time by a diagnostic parameter which determines accuracy of maintaining zero state. For calculations it was assumed that the diagnostic parameter is deviation from nominal value (zero state. Change of deviation value occurs as a result of destructive processes which occur during service. For estimation of deviation increasing rate in probabilistic sense, was used a difference equation from which, after transformation, Fokker-Planck differential equation was obtained [4, 11]. A particular solution of the equation is deviation increasing rate density function which was used for determining exceedance probability of limit state. The so-determined probability was then used to determine density function of limit state exceedance time, by increasing deviation. Having at disposal the density function of limit state exceedance time one determined service life of a system of maladjustment. In the end, a numerical example based on operational data of selected aircraft [weapon] sights was presented. The elaborated method can be also applied to determining residual life of shipboard devices whose technical state is determined on the basis of analysis of values of diagnostic parameters.

  17. Production, characterization and stability of organic solar cell devices

    Energy Technology Data Exchange (ETDEWEB)

    Gevorgyan, S.A.

    2010-01-15

    Despite the fact that the field of organic photovoltaics (OPVs) is in a rapid progress, organic solar cells continue taking backstage roll in the growing markets of various solar technologies. The main challenge of the field is to develop devices that would possess all the optimal properties required for efficient, stable and cheap solar cells, i.e. devices that can deliver high photoconversion efficiencies and long lifetimes and can be efficiently produced in large scales using roll-to-roll coating technologies. This dissertation is primarily devoted to the issues of photoconversion efficiency and device lifetimes. In particular, descriptions of some practical approaches for different device designs and processing of active layer for typical small scale OPV devices were presented. The emphasis was put on some optimizing techniques for processing of active layer that can significantly improve the device photoconversion efficiency. The techniques were further applied for manufacturing and characterization of solar cell devices based on various materials. In particular, a number of thermocleavable polymers were studied and devices based on such materials were produced and characterized. The applicability of such materials in photovoltaic devices was shown and further challenges were discussed. Another task of this work was to manufacture and study inverted device structures and compare their properties with normal structure based devices. Device based on both structure were successfully produced with same level of performance in terms of photoconversion efficiency, yet with totally different stability performance. As another task, metal oxides, such as MoO{sub 3} or V{sub 2}O{sub 5} were studied in solar cell devices as buffer layers instead of PEDOT:PSS. Although the device efficiencies obtained with metal oxides were inferior to PEDOT based device, it was shown that such materials can possibly improve the device efficiency if the processing of the layers is

  18. Microfluidic application-specific integrated device for monitoring direct cell-cell communication via gap junctions between individual cell pairs

    Science.gov (United States)

    Lee, Philip J.; Hung, Paul J.; Shaw, Robin; Jan, Lily; Lee, Luke P.

    2005-05-01

    Direct cell-cell communication between adjacent cells is vital for the development and regulation of functional tissues. However, current biological techniques are difficult to scale up for high-throughput screening of cell-cell communication in an array format. In order to provide an effective biophysical tool for the analysis of molecular mechanisms of gap junctions that underlie intercellular communication, we have developed a microfluidic device for selective trapping of cell-pairs and simultaneous optical characterizations. Two different cell populations can be brought into membrane contact using an array of trapping channels with a 2μm by 2μm cross section. Device operation was verified by observation of dye transfer between mouse fibroblasts (NIH3T3) placed in membrane contact. Integration with lab-on-a-chip technologies offers promising applications for cell-based analytical tools such as drug screening, clinical diagnostics, and soft-state biophysical devices for the study of gap junction protein channels in cellular communications. Understanding electrical transport mechanisms via gap junctions in soft membranes will impact quantitative biomedical sciences as well as clinical applications.

  19. SeleCon: Scalable IoT Device Selection and Control Using Hand Gestures.

    Science.gov (United States)

    Alanwar, Amr; Alzantot, Moustafa; Ho, Bo-Jhang; Martin, Paul; Srivastava, Mani

    2017-04-01

    Although different interaction modalities have been proposed in the field of human-computer interface (HCI), only a few of these techniques could reach the end users because of scalability and usability issues. Given the popularity and the growing number of IoT devices, selecting one out of many devices becomes a hurdle in a typical smarthome environment. Therefore, an easy-to-learn, scalable, and non-intrusive interaction modality has to be explored. In this paper, we propose a pointing approach to interact with devices, as pointing is arguably a natural way for device selection. We introduce SeleCon for device selection and control which uses an ultra-wideband (UWB) equipped smartwatch. To interact with a device in our system, people can point to the device to select it then draw a hand gesture in the air to specify a control action. To this end, SeleCon employs inertial sensors for pointing gesture detection and a UWB transceiver for identifying the selected device from ranging measurements. Furthermore, SeleCon supports an alphabet of gestures that can be used for controlling the selected devices. We performed our experiment in a 9 m -by-10 m lab space with eight deployed devices. The results demonstrate that SeleCon can achieve 84.5% accuracy for device selection and 97% accuracy for hand gesture recognition. We also show that SeleCon is power efficient to sustain daily use by turning off the UWB transceiver, when a user's wrist is stationary.

  20. Device for selectively securing an object to a shaft

    International Nuclear Information System (INIS)

    Calizano, F.; Chauvel, M.

    1984-01-01

    A magnetic tape reel is secured to a reel drive motor shaft by a device including a hub secured to the shaft, a plurality of shoes, and actuating means for thrusting the shoes against the reel and for releasing them from contact with the reel. The securing device includes a cam mounted on the shaft in combination with a locking device including the cam periphery. The locking device thrusts the shoes against the object and is operated by rotation of the motor. The cam is immobilized in rotation while the shoes are locked

  1. Live cell refractometry using microfluidic devices.

    Science.gov (United States)

    Lue, Niyom; Popescu, Gabriel; Ikeda, Takahiro; Dasari, Ramachandra R; Badizadegan, Kamran; Feld, Michael S

    2006-09-15

    Using Hilbert phase microscopy for extracting quantitative phase images, we measured the average refractive index associated with live cells in culture. To decouple the contributions to the phase signal from the cell refractive index and thickness, we confined the cells in microchannels. The results are confirmed by comparison with measurements of spherical cells in suspension.

  2. Emerging Semitransparent Solar Cells: Materials and Device Design.

    Science.gov (United States)

    Tai, Qidong; Yan, Feng

    2017-09-01

    Semitransparent solar cells can provide not only efficient power-generation but also appealing images and show promising applications in building integrated photovoltaics, wearable electronics, photovoltaic vehicles and so forth in the future. Such devices have been successfully realized by incorporating transparent electrodes in new generation low-cost solar cells, including organic solar cells (OSCs), dye-sensitized solar cells (DSCs) and organometal halide perovskite solar cells (PSCs). In this review, the advances in the preparation of semitransparent OSCs, DSCs, and PSCs are summarized, focusing on the top transparent electrode materials and device designs, which are all crucial to the performance of these devices. Techniques for optimizing the efficiency, color and transparency of the devices are addressed in detail. Finally, a summary of the research field and an outlook into the future development in this area are provided. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Quantum dot optoelectronic devices: lasers, photodetectors and solar cells

    International Nuclear Information System (INIS)

    Wu, Jiang; Chen, Siming; Seeds, Alwyn; Liu, Huiyun

    2015-01-01

    Nanometre-scale semiconductor devices have been envisioned as next-generation technologies with high integration and functionality. Quantum dots, or the so-called ‘artificial atoms’, exhibit unique properties due to their quantum confinement in all 3D. These unique properties have brought to light the great potential of quantum dots in optoelectronic applications. Numerous efforts worldwide have been devoted to these promising nanomaterials for next-generation optoelectronic devices, such as lasers, photodetectors, amplifiers, and solar cells, with the emphasis on improving performance and functionality. Through the development in optoelectronic devices based on quantum dots over the last two decades, quantum dot devices with exceptional performance surpassing previous devices are evidenced. This review describes recent developments in quantum dot optoelectronic devices over the last few years. The paper will highlight the major progress made in 1.3 μm quantum dot lasers, quantum dot infrared photodetectors, and quantum dot solar cells. (topical review)

  4. Cell structure for electrochemical devices and method of making same

    Science.gov (United States)

    Kaun, Thomas D.

    1993-01-01

    An electrochemical device comprises a plurality of cells, each cell including a laminate cell membrane, made up of a separator/electrolyte means interposed between alternating positive and negative electrodes, each type of electrode being respectively in common contact to a single current collector.

  5. 21 CFR 864.6160 - Manual blood cell counting device.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Manual blood cell counting device. 864.6160 Section 864.6160 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... count red blood cells, white blood cells, or blood platelets. (b) Classification. Class I (general...

  6. Cell jammers, GPS jammers, and other jamming devices.

    Science.gov (United States)

    2012-10-15

    We caution consumers that it is against the law to use a cell or GPS jammer or any other type of device that blocks, : jams or interferes with authorized communications, as well as to import, advertise, sell, or ship such a device. The : FCC Enforcem...

  7. Improving Perovskite Solar Cells: Insights From a Validated Device Model

    NARCIS (Netherlands)

    Sherkar, Tejas S.; Momblona, Cristina; Gil-Escrig, Lidon; Bolink, Henk J.; Koster, L. Jan Anton

    2017-01-01

    To improve the efficiency of existing perovskite solar cells (PSCs), a detailed understanding of the underlying device physics during their operation is essential. Here, a device model has been developed and validated that describes the operation of PSCs and quantitatively explains the role of

  8. Device operation of organic tandem solar cells

    NARCIS (Netherlands)

    Hadipour, A.; de Boer, B.; Blom, P. W. M.

    2008-01-01

    A generalized methodology is developed to obtain the current-voltage characteristic of polymer tandem solar cells by knowing the electrical performance of both sub cells. We demonstrate that the electrical characteristics of polymer tandem solar cells are correctly predicted for both the series and

  9. Single cell electroporation using microfluidic devices

    NARCIS (Netherlands)

    le Gac, Severine; van den Berg, Albert; Lindstrom, S.; Andersson, Helene

    2012-01-01

    Electroporation is a powerful technique to increase the permeability of cell membranes and subsequently introduce foreign materials into cells. Pores are created in the cell membrane upon application of an electric fi eld (kV/cm). Most applications employ bulk electroporation, at the scale of 1 mL

  10. Microfluidic device for high-yield pairing and fusion of stem cells with somatic cells

    Science.gov (United States)

    Gel, Murat; Hirano, Kunio; Oana, Hidehiro; Kotera, Hidetoshi; Tada, Takashi; Washizu, Masao

    2011-12-01

    Electro cell fusion has significant potential as a biotechnology tool with applications ranging from antibody production to cellular reprogramming. However due to low fusion efficiency of the conventional electro fusion methodology the true potential of the technique has not been reached. In this paper, we report a new method which takes cell fusion efficiency two orders magnitude higher than the conventional electro fusion method. The new method, based on one-toone pairing, fusion and selection of fused cells was developed using a microfabricated device. The device was composed of two microfluidic channels, a micro slit array and a petri dish integrated with electrodes. The electrodes positioned in each channel were used to generate electric field lines concentrating in the micro slits. Cells were introduced into channels and brought in to contact through the micro slit array using dielectrophoresis. The cells in contact were fused by applying a DC pulse to electrodes. As the electric field lines were concentrated at the micro slits the membrane potential was induced only at the vicinity of the micro slits, namely only at the cell-cell contact point. This mechanism assured the minimum damage to cells in the fusion as well as the ability to control the strength and location of induced membrane potential. We introduced mouse embryonic stem cells and mouse embryonic fibroblasts to the microfluidic channels and demonstrated high-yield fusion (> 80%). Post-fusion study showed the method can generate viable hybrids of stem cells and embryonic fibroblasts. Multinucleated hybrid cells adhering on the chip surface were routinely obtained by using this method and on-chip culturing.

  11. Device and materials modeling in PEM fuel cells

    CERN Document Server

    Promislow, Keith

    2009-01-01

    Device and Materials Modeling in PEM Fuel Cells is a specialized text that compiles the mathematical details and results of both device and materials modeling in a single volume. Proton exchange membrane (PEM) fuel cells will likely have an impact on our way of life similar to the integrated circuit. The potential applications range from the micron scale to large scale industrial production. Successful integration of PEM fuel cells into the mass market will require new materials and a deeper understanding of the balance required to maintain various operational states. This book contains articles from scientists who contribute to fuel cell models from both the materials and device perspectives. Topics such as catalyst layer performance and operation, reactor dynamics, macroscopic transport, and analytical models are covered under device modeling. Materials modeling include subjects relating to the membrane and the catalyst such as proton conduction, atomistic structural modeling, quantum molecular dynamics, an...

  12. Femtosecond laser fabrication of optofluidic devices for single cell manipulation

    Directory of Open Access Journals (Sweden)

    Bragheri Francesca

    2015-01-01

    Full Text Available In this work we fabricate and validate two optofludic devices for the manipulation and analysis of single cells. The chips are fabricated by femtosecond laser micromachining exploiting the 3D capabilities of the technique and the inherent perfect alignment between microfluidic channels and optical networks. Both devices have been validated by probing the mechanical properties of different cancer cell lines, which are expected to show different elasticity because of their different metastatic potential.

  13. Organic solar cells fundamentals, devices, and upscaling

    CERN Document Server

    Rand, Barry P

    2014-01-01

    Solution-Processed DonorsB. Burkhart, B. C. ThompsonSmall-Molecule and Vapor-Deposited Organic Photovoltaics R. R. Lunt, R. J. HolmesAcceptor Materials for Solution-Processed Solar Cells Y. HeInterfacial Layers R. Po, C. Carbonera, A. BernardiElectrodes in Organic Photovoltaic Cells S. Yoo, J.-Y. Lee, H. Kim, J. LeeTandem and Multi-Junction Organic Solar Cells J. Gilot, R. A. J. JanssenBulk Heterojunction Morphology Control and Characterization T. Wang, D. G. LidzeyOptical Modeling and Light Management

  14. A Two-Stage Microfluidic Device for the Isolation and Capture of Circulating Tumor Cells

    Science.gov (United States)

    Cook, Andrew; Belsare, Sayali; Giorgio, Todd; Mu, Richard

    2014-11-01

    Analysis of circulating tumor cells (CTCs) can be critical for studying how tumors grow and metastasize, in addition to personalizing treatment for cancer patients. CTCs are rare events in blood, making it difficult to remove CTCs from the blood stream. Two microfluidic devices have been developed to separate CTCs from blood. The first is a double spiral device that focuses cells into streams, the positions of which are determined by cell diameter. The second device uses ligand-coated magnetic nanoparticles that selectively attach to CTCs. The nanoparticles then pull CTCs out of solution using a magnetic field. These two devices will be combined into a single 2-stage microfluidic device that will capture CTCs more efficiently than either device on its own. The first stage depletes the number of blood cells in the sample by size-based separation. The second stage will magnetically remove CTCs from solution for study and culturing. Thus far, size-based separation has been achieved. Research will also focus on understanding the equations that govern fluid dynamics and magnetic fields in order to determine how the manipulation of microfluidic parameters, such as dimensions and flow rate, will affect integration and optimization of the 2-stage device. NSF-CREST: Center for Physics and Chemistry of Materials. HRD-0420516; Department of Defense, Peer Reviewed Medical Research Program Award W81XWH-13-1-0397.

  15. Nanoscale tools to selectively destroy cancer cells.

    Science.gov (United States)

    Boudreault, Pierre-Luc; Arseneault, Mathieu; Otis, François; Voyer, Normand

    2008-05-14

    We present experimental data that demonstrate the potential of synthetic crown ether modified peptide nanostructures to act as selective and efficient chemotherapeutic agents that operate by attacking and destroying cell membranes.

  16. Single cell array impedance analysis in a microfluidic device

    Science.gov (United States)

    Altinagac, Emre; Taskin, Selen; Kizil, Huseyin

    2016-10-01

    Impedance analysis of single cells is presented in this paper. Following the separation of a target cell type by dielectrophoresis in our previous work, this paper focuses on capturing the cells as a single array and performing impedance analysis to point out the signature difference between each cell type. Lab-on-a-chip devices having a titanium interdigitated electrode layer on a glass substrate and a PDMS microchannel are fabricated to capture each cell in a single form and perform impedance analysis. HCT116 (homosapiens colon colorectal carcin) and HEK293 (human embryonic kidney) cells are used in our experiments.

  17. SeleCon: Scalable IoT Device Selection and Control Using Hand Gestures

    Science.gov (United States)

    Alanwar, Amr; Alzantot, Moustafa; Ho, Bo-Jhang; Martin, Paul; Srivastava, Mani

    2018-01-01

    Although different interaction modalities have been proposed in the field of human-computer interface (HCI), only a few of these techniques could reach the end users because of scalability and usability issues. Given the popularity and the growing number of IoT devices, selecting one out of many devices becomes a hurdle in a typical smarthome environment. Therefore, an easy-to-learn, scalable, and non-intrusive interaction modality has to be explored. In this paper, we propose a pointing approach to interact with devices, as pointing is arguably a natural way for device selection. We introduce SeleCon for device selection and control which uses an ultra-wideband (UWB) equipped smartwatch. To interact with a device in our system, people can point to the device to select it then draw a hand gesture in the air to specify a control action. To this end, SeleCon employs inertial sensors for pointing gesture detection and a UWB transceiver for identifying the selected device from ranging measurements. Furthermore, SeleCon supports an alphabet of gestures that can be used for controlling the selected devices. We performed our experiment in a 9m-by-10m lab space with eight deployed devices. The results demonstrate that SeleCon can achieve 84.5% accuracy for device selection and 97% accuracy for hand gesture recognition. We also show that SeleCon is power efficient to sustain daily use by turning off the UWB transceiver, when a user’s wrist is stationary. PMID:29683151

  18. Different Device Architectures for Bulk-Heterojunction Solar Cells

    Directory of Open Access Journals (Sweden)

    Getachew Adam

    2016-08-01

    Full Text Available We report different solar cell designs which allow a simple electrical connection of subsequent devices deposited on the same substrate. By arranging so-called standard and inverted solar-cell architectures next to each other, a serial connection of the two devices can easily be realized by a single compound electrode. In this work, we tested different interfacial layer materials like polyethylenimine (PEI and PEDOT:PSS, and silver as a non-transparent electrode material. We also built organic light emitting diodes applying the same device designs demonstrating the versatility of applied layer stacks. The proposed design should allow the preparation of organic bulk-heterojunction modules with minimized photovoltaically inactive regions at the interconnection of individual devices.

  19. Selected Advances in Nanoelectronic Devices Logic, Memory and RF

    CERN Document Server

    Joodaki, Mojtaba

    2013-01-01

    Nanoelectronics, as a true successor of microelectronics, is certainly a major technology boomer in the 21st century. This has been shown by its several applications and also by its enormous potential to influence all areas of electronics, computers, information technology, aerospace defense, and consumer goods. Although the current semiconductor technology is projected to reach its physical limit in about a decade, nanoscience and nanotechnology promise breakthroughs for the future. The present books provides an in-depth review of the latest advances in the technology of nanoelectronic devices and their developments over the past decades. Moreover, it introduces new concepts for the realization of future nanoelectronic devices. The main focus of the book is on three fundamental branches of semiconductor products or applications: logic, memory, and RF and communication. By pointing out to the key technical challenges, important aspects and characteristics of various designs are used to illustrate mechanisms t...

  20. Cell Selection Using Recursive Bipartite Matching

    DEFF Research Database (Denmark)

    Zakrzewska, Anna; Ruepp, Sarah Renée; Berger, Michael Stübert

    Wireless communication network consist nowadays of multiple standards, as well as cells of different sizes and coverage. Providing the best connection in such environment is a challenging task. We propose a new approach of solving the cell selection problem in heterogeneous networks. The method...

  1. Towards autonomous lab-on-a-chip devices for cell phone biosensing.

    Science.gov (United States)

    Comina, Germán; Suska, Anke; Filippini, Daniel

    2016-03-15

    Modern cell phones are a ubiquitous resource with a residual capacity to accommodate chemical sensing and biosensing capabilities. From the different approaches explored to capitalize on such resource, the use of autonomous disposable lab-on-a-chip (LOC) devices-conceived as only accessories to complement cell phones-underscores the possibility to entirely retain cell phones' ubiquity for distributed biosensing. The technology and principles exploited for autonomous LOC devices are here selected and reviewed focusing on their potential to serve cell phone readout configurations. Together with this requirement, the central aspects of cell phones' resources that determine their potential for analytical detection are examined. The conversion of these LOC concepts into universal architectures that are readable on unaccessorized phones is discussed within this context. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Selective adsorption of bacterial cells onto zeolites.

    Science.gov (United States)

    Kubota, Munehiro; Nakabayashi, Tadashi; Matsumoto, Yuki; Shiomi, Tohru; Yamada, Yusuke; Ino, Keita; Yamanokuchi, Hiroyuki; Matsui, Masayoshi; Tsunoda, Tatsuo; Mizukami, Fujio; Sakaguchi, Kengo

    2008-06-15

    Zeolites adsorb microbial cells on their surfaces and selective adsorption for specific microorganisms was seen with certain zeolites. Tests for the adsorption ability of zeolites were conducted using various established microbial cell lines. Specific cell lines were shown to selectively absorb to certain zeolites, species to species. In order to understand the selectivity of adsorption, we tested adsorption under various pH conditions and determined the zeta-potentials of zeolites and cells. The adsorption of some cell lines depended on the pH, and some microorganisms were preferentially adsorbed at acidic pH. The values of zeta-potentials were used for calculating the electric double layer interaction energy between zeolites and microbial cells. There was a correlation between the experimental adsorption results and the interaction energy. Moreover, we evaluated the surface hydrophobicity of bacterial cells by using the microbial adherence to hydrocarbon (MATH) assay. In addition, we also applied this method for zeolites to quantify relative surface hydrophobicity. As a result, we found a correlation between the adsorption results and the hydrophobicity of bacterial cells and zeolites. These results suggested that adsorption could be explained mainly by electric double layer interactions and hydrophobic interactions. Finally, by using the zeolites Na-BEA and H-Y, we succeeded in clearly separating three representative microbes from a mixture of Escherichia coli, Bacillus subtilis and Staphylococcus aureus. Zeolites could adsorb each of the bacterial cell species with high selectivity even from a mixed suspension. Zeolites can therefore be used as effective carrier materials to provide an easy, rapid and accurate method for cell separation.

  3. Blindness and Selective Mutism: One Student's Response to Voice-Output Devices

    Science.gov (United States)

    Holley, Mary; Johnson, Ashli; Herzberg, Tina

    2014-01-01

    This case study was designed to measure the response of one student with blindness and selective mutism to the intervention of voice-output devices across two years and two different teachers in two instructional settings. Before the introduction of the voice output devices, the student did not choose to communicate using spoken language or…

  4. Clothing, equipment and devices for personnel protection: Its selection according to occupational risks

    International Nuclear Information System (INIS)

    1989-01-01

    This Venezuelan standard establishes the selection of the type of clothing, equipment and devices for personnel protection, to be used by workers according to the occupational risk they deal with, in order to avoid or to reduce the factors that can, directly or indirectly, affect their physical integrity. For the risks not contemplated in this norm, the selection of the type of clothing, equipment and devices for personnel protection, must be done following the corresponding international standard [es

  5. Microfluidic device for cell capture and impedance measurement.

    Science.gov (United States)

    Jang, Ling-Sheng; Wang, Min-How

    2007-10-01

    This work presents a microfluidic device to capture physically single cells within microstructures inside a channel and to measure the impedance of a single HeLa cell (human cervical epithelioid carcinoma) using impedance spectroscopy. The device includes a glass substrate with electrodes and a PDMS channel with micro pillars. The commercial software CFD-ACE+ is used to study the flow of the microstructures in the channel. According to simulation results, the probability of cell capture by three micro pillars is about 10%. An equivalent circuit model of the device is established and fits closely to the experimental results. The circuit can be modeled electrically as cell impedance in parallel with dielectric capacitance and in series with a pair of electrode resistors. The system is operated at low frequency between 1 and 100 kHz. In this study, experiments show that the HeLa cell is successfully captured by the micro pillars and its impedance is measured by impedance spectroscopy. The magnitude of the HeLa cell impedance declines at all operation voltages with frequency because the HeLa cell is capacitive. Additionally, increasing the operation voltage reduces the magnitude of the HeLa cell because a strong electric field may promote the exchange of ions between the cytoplasm and the isotonic solution. Below an operating voltage of 0.9 V, the system impedance response is characteristic of a parallel circuit at under 30 kHz and of a series circuit at between 30 and 100 kHz. The phase of the HeLa cell impedance is characteristic of a series circuit when the operation voltage exceeds 0.8 V because the cell impedance becomes significant.

  6. Evaluating Varied Label Designs for Use with Medical Devices: Optimized Labels Outperform Existing Labels in the Correct Selection of Devices and Time to Select.

    Directory of Open Access Journals (Sweden)

    Laura Bix

    Full Text Available Effective standardization of medical device labels requires objective study of varied designs. Insufficient empirical evidence exists regarding how practitioners utilize and view labeling.Measure the effect of graphic elements (boxing information, grouping information, symbol use and color-coding to optimize a label for comparison with those typical of commercial medical devices.Participants viewed 54 trials on a computer screen. Trials were comprised of two labels that were identical with regard to graphics, but differed in one aspect of information (e.g., one had latex, the other did not. Participants were instructed to select the label along a given criteria (e.g., latex containing as quickly as possible. Dependent variables were binary (correct selection and continuous (time to correct selection.Eighty-nine healthcare professionals were recruited at Association of Surgical Technologists (AST conferences, and using a targeted e-mail of AST members.Symbol presence, color coding and grouping critical pieces of information all significantly improved selection rates and sped time to correct selection (α = 0.05. Conversely, when critical information was graphically boxed, probability of correct selection and time to selection were impaired (α = 0.05. Subsequently, responses from trials containing optimal treatments (color coded, critical information grouped with symbols were compared to two labels created based on a review of those commercially available. Optimal labels yielded a significant positive benefit regarding the probability of correct choice ((P<0.0001 LSM; UCL, LCL: 97.3%; 98.4%, 95.5%, as compared to the two labels we created based on commercial designs (92.0%; 94.7%, 87.9% and 89.8%; 93.0%, 85.3% and time to selection.Our study provides data regarding design factors, namely: color coding, symbol use and grouping of critical information that can be used to significantly enhance the performance of medical device labels.

  7. Design optimization of a helical endothelial cell culture device.

    Science.gov (United States)

    Van Doormaal, Mark A; Ethier, C Ross

    2010-10-01

    The specific roles of mass transfer and fluid dynamic stresses on endothelial function, important in atherogenesis, are not known. Further, the effects of mass transfer and fluid dynamic stresses are difficult to separate because areas of "abnormal" mass transfer and "abnormal" wall shear stress tend to co-localize (where abnormal is defined as any deviation from the mass transfer rate or wall shear stress present in a long straight artery with the same flow rate and diameter). Our goal was to design a cell culture device which gives maximum separation between areas of abnormal shear stress and areas of abnormal mass transfer. We used design optimization principles to design a helical cell culture device. Using shear stress and mass transfer fields predicted by solving the governing equations, the area of the device which was exposed to low rates of mass transfer and normal levels of wall shear stress was determined. The design optimization method then maximized this area by varying the design variables, resulting in the optimum design. The optimum design had Reynolds number = 50, helical radius = 3.23 and helical pitch = 3.82. The area of the device which was exposed to low rates of mass transfer and regular levels of wall shear stress was about 4.5 times the inlet cross-sectional area of the device or about 5% of the device total internal surface area. An optimum design was successfully determined and the methodology used was shown to be robust. The area of the device which was exposed to low rates of mass transfer and regular levels of wall shear stress occurred in a defined region which should aid further experimental work.

  8. Acoustic Devices for Particle and Cell Manipulation and Sensing

    Directory of Open Access Journals (Sweden)

    Yongqiang Qiu

    2014-08-01

    Full Text Available An emerging demand for the precise manipulation of cells and particles for applications in cell biology and analytical chemistry has driven rapid development of ultrasonic manipulation technology. Compared to the other manipulation technologies, such as magnetic tweezing, dielectrophoresis and optical tweezing, ultrasonic manipulation has shown potential in a variety of applications, with its advantages of versatile, inexpensive and easy integration into microfluidic systems, maintenance of cell viability, and generation of sufficient forces to handle particles, cells and their agglomerates. This article briefly reviews current practice and reports our development of various ultrasonic standing wave manipulation devices, including simple devices integrated with high frequency (>20 MHz ultrasonic transducers for the investigation of biological cells and complex ultrasonic transducer array systems to explore the feasibility of electronically controlled 2-D and 3-D manipulation. Piezoelectric and passive materials, fabrication techniques, characterization methods and possible applications are discussed. The behavior and performance of the devices have been investigated and predicted with computer simulations, and verified experimentally. Issues met during development are highlighted and discussed. To assist long term practical adoption, approaches to low-cost, wafer level batch-production and commercialization potential are also addressed.

  9. Characterization of a novel miniature cell culture device

    Science.gov (United States)

    Moore, Sandra K.; Kleis, Stanley J.

    2008-05-01

    Recent advancements in the field of microfluidics have generated much interest in the advent of a miniaturized cell culture device. In this study, we developed a novel miniature culture system (cells, either prokaryotic or eukaryotic in type, for both 1 g and microgravity applications. The miniature culture system may advance the development of microanalytical remote monitoring tools such as biological sentinels, biosensors, and lab-on-a-chip. Integrating the autonomous miniature culture system with a microanalytical device makes a powerful biological tool. Cells can be cultured long-term, harvested, and released directly into an analytical tool without the need for human interaction through fluid dynamic manipulations. This work characterizes the miniature bioreactor system through numerical and experimental proof of concept studies.

  10. Photocharge accumulation and recombination in perovskite solar cells regarding device performance and stability

    Science.gov (United States)

    Li, Yusheng; Li, Yiming; Shi, Jiangjian; Li, Hongshi; Zhang, Huiyin; Wu, Jionghua; Li, Dongmei; Luo, Yanhong; Wu, Huijue; Meng, Qingbo

    2018-01-01

    Photocharge accumulation and recombination in perovskite solar cells have been systematically investigated in this paper by electrochemical spectroscopy and transient photocurrent/photovoltage methods. It is found that the non-equilibrium photocharges stored in the selective charge transport layers follow a backward recombination mechanism. That is, the photocharges are first captured by the interface defects corresponding to the fast photovoltage decay, while the bulk charge recombination instead of the diffusion process dominates the slow photovoltage decay process. Further investigation reveals that the device degradation preferentially takes place at the interface under working conditions, which thus can confirm the importance of interface engineering to enhance the device stability.

  11. Selection of restriction endonucleases using artificial cells.

    Science.gov (United States)

    Zheng, Yu; Roberts, Richard J

    2007-01-01

    We describe in this article an in vitro system for the selection of restriction endonucleases using artificial cells. The artificial cells are generated in the form of a water-in-oil emulsion by in vitro compartmentalization. Each aqueous compartment contains a reconstituted transcription/translation mix along with the dispersed DNA templates. In the compartments containing endonuclease genes, an endonuclease expressed in vitro cleaves its own DNA template adjacent to the gene, leaving a sticky end. The pooled DNA templates are then ligated to an adaptor with a compatible end. The endonuclease genes are then enriched by adaptor-specific PCR on the ligation mix. We demonstrate that the system can achieve at least 100-fold enrichment in a single round of selection. It is sensitive enough to enrich an active endonuclease gene from a 1:10(5) model library in 2-3 rounds of selection. Finally, we describe experiments where we selected endonuclease genes directly from a bacterial genomic DNA source in three rounds of selections: the known PstI gene from Providencia stuartii and the new TspMI gene from Thermus sp. manalii. This method provides a unique tool for cloning restriction endonuclease genes and has many other potential applications.

  12. Microgravity-Enhanced Stem Cell Selection

    Science.gov (United States)

    Claudio, Pier Paolo; Valluri, Jagan

    2011-01-01

    Stem cells, both embryonic and adult, promise to revolutionize the practice of medicine in the future. In order to realize this potential, a number of hurdles must be overcome. Most importantly, the signaling mechanisms necessary to control the differentiation of stem cells into tissues of interest remain to be elucidated, and much of the present research on stem cells is focused on this goal. Nevertheless, it will also be essential to achieve large-scale expansion and, in many cases, assemble cells in 3D as transplantable tissues. To this end, microgravity analog bioreactors can play a significant role. Microgravity bioreactors were originally conceived as a tool to study the cellular responses to microgravity. However, the technology can address some of the shortcomings of conventional cell culture systems; namely, the deficiency of mass transport in static culture and high mechanical shear forces in stirred systems. Unexpectedly, the conditions created in the vessel were ideal for 3D cell culture. Recently, investigators have demonstrated the capability of the microgravity bioreactors to expand hematopoietic stem cells compared to static culture, and facilitate the differentiation of umbilical cord stem cells into 3D liver aggregates. Stem cells are capable of differentiating into functional cells. However, there are no reliable methods to induce the stem cells to form specific cells or to gain enough cells for transplantation, which limits their application in clinical therapy. The aim of this study is to select the best experimental setup to reach high proliferation levels by culturing these cells in a microgravity-based bioreactor. In typical cell culture, the cells sediment to the bottom surface of their container and propagate as a one-cell-layer sheet. Prevention of such sedimentation affords the freedom for self-assembly and the propagation of 3D tissue arrays. Suspension of cells is easily achievable using stirred technologies. Unfortunately, in

  13. Selection of High Strength Encapsulant for MEMS Devices Undergoing High Pressure Packaging

    OpenAIRE

    Hamzah, A.A.; Husaini, Y.; Majlis, B.Y.; Ahmad, I.

    2007-01-01

    Submitted on behalf of EDA Publishing Association (http://irevues.inist.fr/EDA-Publishing); International audience; Deflection behavior of several encapsulant materials under uniform pressure was studied to determine the best encapsulant for MEMS device. Encapsulation is needed to protect movable parts of MEMS devices during high pressure transfer molded packaging process. The selected encapsulant material has to have surface deflection of less than 5 ?m under 100 atm vertical loading. Deflec...

  14. Improved Selectivity From a Wavelength Addressable Device for Wireless Stimulation of Neural Tissue

    Directory of Open Access Journals (Sweden)

    Elif Ç. Seymour

    2014-02-01

    Full Text Available Electrical neural stimulation with micro electrodes is a promising technique for restoring lost functions in the central nervous system as a result of injury or disease. One of the problems related to current neural stimulators is the tissue response due to the connecting wires and the presence of a rigid electrode inside soft neural tissue. We have developed a novel, optically activated, microscale photovoltaic neurostimulator based on a custom layered compound semiconductor heterostructure that is both wireless and has a comparatively small volume. Optical activation provides a wireless means of energy transfer to the neurostimulator, eliminating wires and the associated complications. This neurostimulator was shown to evoke action potentials and a functional motor response in the rat spinal cord. In this work, we extend our design to include wavelength selectivity and thus allowing independent activation of devices. As a proof of concept, we fabricated two different microscale devices with different spectral responsivities in the near-infrared region. We assessed the improved addressability of individual devices via wavelength selectivity as compared to spatial selectivity alone through on-bench optical measurements of the devices in combination with an in vivo light intensity profile in the rat cortex obtained in a previous study. We show that wavelength selectivity improves the individual addressability of the floating stimulators, thus increasing the number of devices that can be implanted in close proximity to each other.

  15. Solid-state devices for detection of DNA, protein biomarkers and cells

    Science.gov (United States)

    Asghar, Waseem

    Nanobiotechnology and BioMEMS have had tremendous impact on biosensing in the areas of cancer cell detection and therapeutics, disease diagnostics, proteomics and DNA analysis. Diseases are expressed on all levels including DNA, protein, cell and tissue. Therefore it is very critical to develop biosensors at each level. The power of the nanotechnology lies in the fact that we can fabricate devices on all scales from micro to nano. This dissertation focuses on four areas: 1) Development of nanopore sensors for DNA analysis; 2) Development of micropore sensors for early detection of circulating tumor cells (CTCs) from whole blood; 3) Synthesis of nano-textured substrates for cancer isolation and tissue culture applications; 4) Fabrication of nanoscale break-junctions. All of these sensors are fabricated using standard silicon processing techniques. Pulsed plasma polymer deposition is also utilized to control the density of the biosensor surface charges. These devices are then used for efficient detection of DNA, proteins and cells, and can be potentially used in point-of-care systems. Overall, our designed biosensing platforms offer improved selectivity, yield and reliability. Novel approaches to nanopore shrinking are simple, reliable and do not change the material composition around the pore boundary. The micropores provide a direct interface to distinguish CTCs from normal cell without requiring fluorescent dyes and surface functionalization. Nano-textured surfaces and break-junctions can be used for enhanced adhesion of cells and selective detection of proteins respectively.

  16. High-selectivity cytology via lab-on-a-disc western blotting of individual cells.

    Science.gov (United States)

    Kim, John J; Sinkala, Elly; Herr, Amy E

    2017-02-28

    Cytology of sparingly available cell samples from both clinical and experimental settings would benefit from high-selectivity protein tools. To minimize cell handling losses in sparse samples, we design a multi-stage assay using a lab-on-a-disc that integrates cell handling and subsequent single-cell western blotting (scWestern). As the two-layer microfluidic device rotates, the induced centrifugal force directs dissociated cells to dams, which in turn localize the cells over microwells. Cells then sediment into the microwells, where the cells are lysed and subjected to scWestern. Taking into account cell losses from loading, centrifugation, and lysis-buffer exchange, our lab-on-a-disc device handles cell samples with as few as 200 cells with 75% cell settling efficiencies. Over 70% of microwells contain single cells after the centrifugation. In addition to cell settling efficiency, cell-size filtration from a mixed population of two cell lines is also realized by tuning the cell time-of-flight during centrifugation (58.4% settling efficiency with 6.4% impurity). Following the upstream cell handling, scWestern analysis detects four proteins (GFP, β-TUB, GAPDH, and STAT3) in a glioblastoma cell line. By integrating the lab-on-a-disc cell preparation and scWestern analysis, our platform measures proteins from sparse cell samples at single-cell resolution.

  17. A passive cold storage device economic model to evaluate selected immunization location scenarios.

    Science.gov (United States)

    Norman, Bryan A; Nourollahi, Sevnaz; Chen, Sheng-I; Brown, Shawn T; Claypool, Erin G; Connor, Diana L; Schmitz, Michelle M; Rajgopal, Jayant; Wateska, Angela R; Lee, Bruce Y

    2013-10-25

    The challenge of keeping vaccines cold at health posts given the unreliability of power sources in many low- and middle-income countries and the expense and maintenance requirements of solar refrigerators has motivated the development of passive cold storage devices (PCDs), containers that keep vaccines cold without using an active energy source. With different PCDs under development, manufacturers, policymakers and funders need guidance on how varying different PCD characteristics may affect the devices' cost and utility. We developed an economic spreadsheet model representing the lowest two levels of a typical Expanded Program on Immunization (EPI) vaccine supply chain: a district store, the immunization locations that the district store serves, and the transport vehicles that operate between the district store and the immunization locations. The model compares the use of three vaccine storage device options [(1) portable PCDs, (2) stationary PCDs, or (3) solar refrigerators] and allows the user to vary different device (e.g., size and cost) and scenario characteristics (e.g., catchment area population size and vaccine schedule). For a sample set of select scenarios and equipment specification, we found the portable PCD to generally be better suited to populations of 5,000 or less. The stationary PCD replenished once per month can be a robust design especially with a 35L capacity and a cost of $2,500 or less. The solar device was generally a reasonable alternative for most of the scenarios explored if the cost was $2,100 or less (including installation). No one device type dominated over all explored circumstances. Therefore, the best device may vary from country-to-country and location-to-location within a country. This study introduces a quantitative model to help guide PCD development. Although our selected set of explored scenarios and device designs was not exhaustive, future explorations can further alter model input values to represent additional scenarios

  18. Development of an electronic device quality aluminum antimonide (AlSb) semiconductor for solar cell applications

    Energy Technology Data Exchange (ETDEWEB)

    Sherohman, John W; Yee, Jick Hong; Combs, III, Arthur W

    2014-11-11

    Electronic device quality Aluminum Antimonide (AlSb)-based single crystals produced by controlled atmospheric annealing are utilized in various configurations for solar cell applications. Like that of a GaAs-based solar cell devices, the AlSb-based solar cell devices as disclosed herein provides direct conversion of solar energy to electrical power.

  19. 78 FR 27441 - NIJ Evaluation of Hand-Held Cell Phone Detector Devices

    Science.gov (United States)

    2013-05-10

    ... of Justice Programs NIJ Evaluation of Hand-Held Cell Phone Detector Devices AGENCY: National...) is soliciting interest in supplying hand-held cell phone detector devices for participation in an... soliciting interest in supplying hand-held cell phone detector devices for participation in an evaluation by...

  20. Design, construction, and characterization of high-performance membrane fusion devices with target-selectivity.

    Science.gov (United States)

    Kashiwada, Ayumi; Yamane, Iori; Tsuboi, Mana; Ando, Shun; Matsuda, Kiyomi

    2012-01-31

    Membrane fusion proteins such as the hemagglutinin glycoprotein have target recognition and fusion accelerative domains, where some synergistically working elements are essential for target-selective and highly effective native membrane fusion systems. In this work, novel membrane fusion devices bearing such domains were designed and constructed. We selected a phenylboronic acid derivative as a recognition domain for a sugar-like target and a transmembrane-peptide (Leu-Ala sequence) domain interacting with the target membrane, forming a stable hydrophobic α-helix and accelerating the fusion process. Artificial membrane fusion behavior between the synthetic devices in which pilot and target liposomes were incorporated was characterized by lipid-mixing and inner-leaflet lipid-mixing assays. Consequently, the devices bearing both the recognition and transmembrane domains brought about a remarkable increase in the initial rate for the membrane fusion compared with the devices containing the recognition domain alone. In addition, a weakly acidic pH-responsive device was also constructed by replacing three Leu residues in the transmembrane-peptide domain by Glu residues. The presence of Glu residues made the acidic pH-dependent hydrophobic α-helix formation possible as expected. The target-selective liposome-liposome fusion was accelerated in a weakly acidic pH range when the Glu-substituted device was incorporated in pilot liposomes. The use of this pH-responsive device seems to be a potential strategy for novel applications in a liposome-based delivery system. © 2011 American Chemical Society

  1. Performance evaluation of aluminum/phosphate cell for powering small electronic devices

    Directory of Open Access Journals (Sweden)

    Gymama Slaughter

    2015-12-01

    Full Text Available We report on an innovative membrane-free aluminum/phosphate cell based on the activation of aluminum (Al as anodic material using ZnO nanocrystal in phosphate rich electrolyte that is capable of generating sufficient power to power a light-emitting diode (LED, selected as a model of a small electronic device. The energy from the cell is periodically supplied in high power bursts due to the charge and discharge cycle of the capacitor. The entire process is controlled by a switched capacitor regulator. The Al/phosphate cell was studied in neutral 100 mM phosphate buffer solution (7.4 at a temperature of 25 °C. We demonstrate that two Al/phosphate cells connected in series can generate an open circuit voltage (Voc up to 1.66 V to continuously power a LED via a switched capacitor regulator circuit. The switched capacitor regulator circuit enabled the 1 μF capacitor to store the incoming power from the cell and discharge it in a large power burst to supply the necessary drive strength required by the LED. This new Al/phosphate cell configuration is a ‘green’ alternative to the use of glucose abiotic and biofuel cells for powering ultra-low power implantable electronic devices.

  2. Passive direct methanol fuel cells for portable electronic devices

    International Nuclear Information System (INIS)

    Achmad, F.; Kamarudin, S.K.; Daud, W.R.W.; Majlan, E.H.

    2011-01-01

    Due to the increasing demand for electricity, clean, renewable energy resources must be developed. Thus, the objective of the present study was to develop a passive direct methanol fuel cell (DMFC) for portable electronic devices. The power output of six dual DMFCs connected in series with an active area of 4 cm 2 was approximately 600 mW, and the power density of the DMFCs was 25 mW cm -2 . The DMFCs were evaluated as a power source for mobile phone chargers and media players. The results indicated that the open circuit voltage of the DMFC was between 6.0 V and 6.5 V, and the voltage under operating conditions was 4.0 V. The fuel cell was tested on a variety of cell phone chargers, media players and PDAs. The cost of energy consumption by the proposed DMFC was estimated to be USD 20 W -1 , and the cost of methanol is USD 4 kW h. Alternatively, the local conventional electricity tariff is USD 2 kW h. However, for the large-scale production of electronic devices, the cost of methanol will be significantly lower. Moreover, the electricity tariff is expected to increase due to the constraints of fossil fuel resources and pollution. As a result, DMFCs will become competitive with conventional power sources.

  3. Ventricular assist devices for heart failure: a focus on patient selection and complications

    Directory of Open Access Journals (Sweden)

    Cipriani M

    2014-09-01

    Full Text Available Manlio Cipriani, Vincenzo De Simone, Luciana D'Angelo, Enrico Perna, Marzia Lilliu, Virginia Bovolo, Fabrizio Oliva, Maria Frigerio Cardiovascular and Thoracic Department, A De Gasperis Niguarda Ca' Granda Hospital, Milan, Italy Abstract: Heart transplantation represents the “gold standard” for the treatment of patients with end-stage heart failure, but remains challenged by inadequate donor supply, finite graft survival, and long-term complications arising from immunosuppressive therapy. In addition, a lot of patients waiting for a heart transplant experience clinical deterioration, and other patients become ineligible to undergo this treatment due to their age or relevant comorbidities. Left ventricular assist devices have emerged as a valid therapeutic option for advanced heart failure. In recent years, we have seen significant advances not only in the technologies available, but also in patient selection, indications for use, and management after implantation. Consequently, there has been an increase in the number of implants and an improvement in the survival rate and quality of life for these patients. At the same time, there are new challenges on the horizon. Patient selection is a difficult process, based on clinical and imaging parameters and risk scores, and more data are needed to refine patient selection criteria and the timing of the implant. Left ventricular assist device-related complications are still a serious problem, causing adverse events and hospital readmissions. Continuous progress in the development of these implantable devices, such as a further reduction in size and hopefully the abolition of the external driveline, will probably make ventricular assist devices an option also for less advanced stages of heart failure. Here, we discuss the current indications for left ventricular assist device implantation, patient selection criteria, and the most frequent complications associated with these devices. Keywords

  4. DNA Translocation and Cell Electroporation in Micro and Nanofluidic Devices

    Science.gov (United States)

    Gupta, Cherry

    The cell membrane is made of a thin (˜ 5nm) lipid bilayer which serves as an effective insulator and diffusion barrier for entities external to the cell from entering the cell. However, for research, diagnostic and therapeutic purposes, there is a need to deliver molecules of interest to the interior of live cells. This is usually accomplished by two methods: (a) carrier mediated delivery which consists of encapsulating the gene/molecule of interest either in an empty viral capsid or in chemically formulated lipoplex or polyplex nanoparticles, or (b) physical methods of delivery, which include the use of different kinds of forces to create reversible pores on the cell membrane (sonoporation, electroporation) or directly inject molecules to the cell cytosol (Gene Gun, microinjection). Of the aforementioned techniques, electroporation is the most commonly used due to it simplicity and ease of use. Our group recently demonstrated a nanochannel based electroporation (NEP) technique, in which two microchannels (˜40 m diameter) are connected by a nanochannel (˜ 200-400 mum diameter) in the center. A cell is positioned in one microchannel such that it makes contact with the nanochannel and transfection agents are placed in the other microchannel. An external electric field applied across the device locally porates the cell where it touches the nancohannel and drives the transfection agents into the cell. Besides maintaining high cell viability and achieving dose control, an important feature of NEP is the delivery of large molecules such as plasmids and quantum dots directly into the cell cytosol. In contrast, delivery of large plasmids during bulk electroporation, wherein cells and genes/plasmids are mixed in a buffered medium and an external electric field is applied across the mixture which electroporates the cells, is via formation of cell membrane bound aggregates which get endocytosed post pulsation. Various mechanisms of DNA transport across the membrane have

  5. Single cell detection using a glass-based optofluidic device fabricated by femtosecond laser pulses.

    Science.gov (United States)

    Kim, Moosung; Hwang, David J; Jeon, Hojeong; Hiromatsu, Kuniaki; Grigoropoulos, Costas P

    2009-01-21

    We demonstrate the fabrication of integrated three-dimensional microchannel and optical waveguide structures inside fused silica for the interrogation and processing of single cells. The microchannels are fabricated by scanning femtosecond laser pulses (523 nm) and subsequent selective wet etching process. Optical waveguides are additionally integrated with the fabricated microchannels by scanning the laser pulse train inside the glass specimen. Single red blood cells (RBC) in diluted human blood inside of the manufactured microchannel were detected by two optical schemes. The first involved sensing the intensity change of waveguide-delivered He-Ne laser light (632.8 nm) induced by the refractive index difference of a cell flowing in the channel. The other approach was via detection of fluorescence emission from dyed RBC excited by Ar laser light (488 nm) delivered by the optical waveguide. The proposed device was tested to detect 23 fluorescent particles per second by increasing the flow rate up to 0.5 microl min(-1). The optical cell detection experiments support potential implementation of a new generation of glass-based optofluidic biochip devices in various single cell treatment processes including laser based cell processing and sensing.

  6. Selective ablation of photovoltaic materials with UV laser sources for monolithic interconnection of devices based on a-Si:H

    Energy Technology Data Exchange (ETDEWEB)

    Molpeceres, C. [Centro Laser UPM, Univ. Politecnica de Madrid, Crta. de Valencia Km 7.3, 28031 Madrid (Spain)], E-mail: carlos.molpeceres@upm.es; Lauzurica, S.; Garcia-Ballesteros, J.J.; Morales, M.; Guadano, G.; Ocana, J.L. [Centro Laser UPM, Univ. Politecnica de Madrid, Crta. de Valencia Km 7.3, 28031 Madrid (Spain); Fernandez, S.; Gandia, J.J. [Dept. de Energias Renovables, Energia Solar Fotovoltaica, CIEMAT, Avda, Complutense 22, 28040 Madrid (Spain); Villar, F.; Nos, O.; Bertomeu, J. [CeRMAE Dept. Fisica Aplicada i Optica, Universitat de Barcelona, Av. Diagonal 647, 08028 Barcelona (Spain)

    2009-03-15

    Lasers are essential tools for cell isolation and monolithic interconnection in thin-film-silicon photovoltaic technologies. Laser ablation of transparent conductive oxides (TCOs), amorphous silicon structures and back contact removal are standard processes in industry for monolithic device interconnection. However, material ablation with minimum debris and small heat affected zone is one of the main difficulty is to achieve, to reduce costs and to improve device efficiency. In this paper we present recent results in laser ablation of photovoltaic materials using excimer and UV wavelengths of diode-pumped solid-state (DPSS) laser sources. We discuss results concerning UV ablation of different TCO and thin-film silicon (a-Si:H and nc-Si:H), focussing our study on ablation threshold measurements and process-quality assessment using advanced optical microscopy techniques. In that way we show the advantages of using UV wavelengths for minimizing the characteristic material thermal affection of laser irradiation in the ns regime at higher wavelengths. Additionally we include preliminary results of selective ablation of film on film structures irradiating from the film side (direct writing configuration) including the problem of selective ablation of ZnO films on a-Si:H layers. In that way we demonstrate the potential use of UV wavelengths of fully commercial laser sources as an alternative to standard backscribing process in device fabrication.

  7. Selective ablation of photovoltaic materials with UV laser sources for monolithic interconnection of devices based on a-Si:H

    International Nuclear Information System (INIS)

    Molpeceres, C.; Lauzurica, S.; Garcia-Ballesteros, J.J.; Morales, M.; Guadano, G.; Ocana, J.L.; Fernandez, S.; Gandia, J.J.; Villar, F.; Nos, O.; Bertomeu, J.

    2009-01-01

    Lasers are essential tools for cell isolation and monolithic interconnection in thin-film-silicon photovoltaic technologies. Laser ablation of transparent conductive oxides (TCOs), amorphous silicon structures and back contact removal are standard processes in industry for monolithic device interconnection. However, material ablation with minimum debris and small heat affected zone is one of the main difficulty is to achieve, to reduce costs and to improve device efficiency. In this paper we present recent results in laser ablation of photovoltaic materials using excimer and UV wavelengths of diode-pumped solid-state (DPSS) laser sources. We discuss results concerning UV ablation of different TCO and thin-film silicon (a-Si:H and nc-Si:H), focussing our study on ablation threshold measurements and process-quality assessment using advanced optical microscopy techniques. In that way we show the advantages of using UV wavelengths for minimizing the characteristic material thermal affection of laser irradiation in the ns regime at higher wavelengths. Additionally we include preliminary results of selective ablation of film on film structures irradiating from the film side (direct writing configuration) including the problem of selective ablation of ZnO films on a-Si:H layers. In that way we demonstrate the potential use of UV wavelengths of fully commercial laser sources as an alternative to standard backscribing process in device fabrication.

  8. Synchrotron radiation infrared microspectroscopy of single living cells in microfluidic devices: advantages, disadvantages and future perspectives

    International Nuclear Information System (INIS)

    Vaccari, L; Birarda, G; Grenci, G; Pacor, S; Businaro, L

    2012-01-01

    The possibility to fully exploit the diagnostic capabilities of SR-IRMS for studying single living cells under physiological conditions is limited by several constrains. First of all, the technology for manufacturing materials transparent to both IR and visible light is quite immature, limiting the design of fluidic devices to simple demountable liquid cells. In addition, the water spectral features become prominent in the Mid IR, hiding several cellular bands and therefore limiting the diagnostic capabilities of SR-IRMS. The overcoming of the so called 'water absorption barrier' requires the improvement of the protocols for the compensation of buffer spectral contributions, a goal that can be achieved also advancing the quality of IR-suitable fluidic devices. In this paper, the technical solutions employed for microfabricating completely sealed IR-visible transparent fluidic devices for living cell analysis will be presented. Several examples of the results obtained in the study of living U937 monocytes subjected to different stimuli will be selected for highlighting both the advantages and the disadvantages offered by our approach for cellular biology.

  9. Design optimization and analysis of selected thermal devices using self-adaptive Jaya algorithm

    International Nuclear Information System (INIS)

    Rao, R.V.; More, K.C.

    2017-01-01

    Highlights: • Self-adaptive Jaya algorithm is proposed for optimal design of thermal devices. • Optimization of heat pipe, cooling tower, heat sink and thermo-acoustic prime mover is presented. • Results of the proposed algorithm are better than the other optimization techniques. • The proposed algorithm may be conveniently used for the optimization of other devices. - Abstract: The present study explores the use of an improved Jaya algorithm called self-adaptive Jaya algorithm for optimal design of selected thermal devices viz; heat pipe, cooling tower, honeycomb heat sink and thermo-acoustic prime mover. Four different optimization case studies of the selected thermal devices are presented. The researchers had attempted the same design problems in the past using niched pareto genetic algorithm (NPGA), response surface method (RSM), leap-frog optimization program with constraints (LFOPC) algorithm, teaching-learning based optimization (TLBO) algorithm, grenade explosion method (GEM) and multi-objective genetic algorithm (MOGA). The results achieved by using self-adaptive Jaya algorithm are compared with those achieved by using the NPGA, RSM, LFOPC, TLBO, GEM and MOGA algorithms. The self-adaptive Jaya algorithm is proved superior as compared to the other optimization methods in terms of the results, computational effort and function evalutions.

  10. A Method for Microencapsulation of Cells and a Device for Its Realization.

    Science.gov (United States)

    Lepekhova, S A; Goldberg, O A; Kravchenko, A A; Batraks, A E; Koval, E V; Kurgansky, I S; Apartsin, K A

    2017-04-01

    The device for cell encapsulation makes it possible to fabricate microcapsules of a preset size with even smooth surface, without defects or adhesion to each other, with viable cells inside the capsule. The cells were derived from newborn piglet pancreases.

  11. Selectivity of Direct Methanol Fuel Cell Membranes.

    Science.gov (United States)

    Aricò, Antonino S; Sebastian, David; Schuster, Michael; Bauer, Bernd; D'Urso, Claudia; Lufrano, Francesco; Baglio, Vincenzo

    2015-11-24

    Sulfonic acid-functionalized polymer electrolyte membranes alternative to Nafion(®) were developed. These were hydrocarbon systems, such as blend sulfonated polyetheretherketone (s-PEEK), new generation perfluorosulfonic acid (PFSA) systems, and composite zirconium phosphate-PFSA polymers. The membranes varied in terms of composition, equivalent weight, thickness, and filler and were investigated with regard to their methanol permeation characteristics and proton conductivity for application in direct methanol fuel cells. The behavior of the membrane electrode assemblies (MEA) was investigated in fuel cell with the aim to individuate a correlation between membrane characteristics and their performance in a direct methanol fuel cell (DMFC). The power density of the DMFC at 60 °C increased according to a square root-like function of the membrane selectivity. This was defined as the reciprocal of the product between area specific resistance and crossover. The power density achieved at 60 °C for the most promising s-PEEK-based membrane-electrode assembly (MEA) was higher than the benchmark Nafion(®) 115-based MEA (77 mW·cm(-2) vs. 64 mW·cm(-2)). This result was due to a lower methanol crossover (47 mA·cm(-2) equivalent current density for s-PEEK vs. 120 mA·cm(-2) for Nafion(®) 115 at 60 °C as recorded at OCV with 2 M methanol) and a suitable area specific resistance (0.15 Ohm cm² for s-PEEK vs. 0.22 Ohm cm² for Nafion(®) 115).

  12. Selectivity of Direct Methanol Fuel Cell Membranes

    Science.gov (United States)

    Aricò, Antonino S.; Sebastian, David; Schuster, Michael; Bauer, Bernd; D’Urso, Claudia; Lufrano, Francesco; Baglio, Vincenzo

    2015-01-01

    Sulfonic acid-functionalized polymer electrolyte membranes alternative to Nafion® were developed. These were hydrocarbon systems, such as blend sulfonated polyetheretherketone (s-PEEK), new generation perfluorosulfonic acid (PFSA) systems, and composite zirconium phosphate–PFSA polymers. The membranes varied in terms of composition, equivalent weight, thickness, and filler and were investigated with regard to their methanol permeation characteristics and proton conductivity for application in direct methanol fuel cells. The behavior of the membrane electrode assemblies (MEA) was investigated in fuel cell with the aim to individuate a correlation between membrane characteristics and their performance in a direct methanol fuel cell (DMFC). The power density of the DMFC at 60 °C increased according to a square root-like function of the membrane selectivity. This was defined as the reciprocal of the product between area specific resistance and crossover. The power density achieved at 60 °C for the most promising s-PEEK-based membrane-electrode assembly (MEA) was higher than the benchmark Nafion® 115-based MEA (77 mW·cm−2 vs. 64 mW·cm−2). This result was due to a lower methanol crossover (47 mA·cm−2 equivalent current density for s-PEEK vs. 120 mA·cm−2 for Nafion® 115 at 60 °C as recorded at OCV with 2 M methanol) and a suitable area specific resistance (0.15 Ohm cm2 for s-PEEK vs. 0.22 Ohm cm2 for Nafion® 115). PMID:26610582

  13. Selectivity of Direct Methanol Fuel Cell Membranes

    Directory of Open Access Journals (Sweden)

    Antonino S. Aricò

    2015-11-01

    Full Text Available Sulfonic acid-functionalized polymer electrolyte membranes alternative to Nafion® were developed. These were hydrocarbon systems, such as blend sulfonated polyetheretherketone (s-PEEK, new generation perfluorosulfonic acid (PFSA systems, and composite zirconium phosphate–PFSA polymers. The membranes varied in terms of composition, equivalent weight, thickness, and filler and were investigated with regard to their methanol permeation characteristics and proton conductivity for application in direct methanol fuel cells. The behavior of the membrane electrode assemblies (MEA was investigated in fuel cell with the aim to individuate a correlation between membrane characteristics and their performance in a direct methanol fuel cell (DMFC. The power density of the DMFC at 60 °C increased according to a square root-like function of the membrane selectivity. This was defined as the reciprocal of the product between area specific resistance and crossover. The power density achieved at 60 °C for the most promising s-PEEK-based membrane-electrode assembly (MEA was higher than the benchmark Nafion® 115-based MEA (77 mW·cm−2 vs. 64 mW·cm−2. This result was due to a lower methanol crossover (47 mA·cm−2 equivalent current density for s-PEEK vs. 120 mA·cm−2 for Nafion® 115 at 60 °C as recorded at OCV with 2 M methanol and a suitable area specific resistance (0.15 Ohm cm2 for s-PEEK vs. 0.22 Ohm cm2 for Nafion® 115.

  14. A novel closed cell culture device for fabrication of corneal epithelial cell sheets.

    Science.gov (United States)

    Nakajima, Ryota; Kobayashi, Toyoshige; Moriya, Noboru; Mizutani, Manabu; Kan, Kazutoshi; Nozaki, Takayuki; Saitoh, Kazuo; Yamato, Masayuki; Okano, Teruo; Takeda, Shizu

    2015-11-01

    Automation technology for cell sheet-based tissue engineering would need to optimize the cell sheet fabrication process, stabilize cell sheet quality and reduce biological contamination risks. Biological contamination must be avoided in clinical settings. A closed culture system provides a solution for this. In the present study, we developed a closed culture device called a cell cartridge, to be used in a closed cell culture system for fabricating corneal epithelial cell sheets. Rabbit limbal epithelial cells were cultured on the surface of a porous membrane with 3T3 feeder cells, which are separate from the epithelial cells in the cell cartridges and in the cell-culture inserts as a control. To fabricate the stratified cell sheets, five different thicknesses of the membranes which were welded to the cell cartridge, were examined. Multilayered corneal epithelial cell sheets were fabricated in cell cartridges that were welded to a 25 µm-thick gas-permeable membrane, which was similar to the results with the cell-culture inserts. However, stratification of corneal epithelial cell sheets did not occur with cell cartridges that were welded to 100-300 µm-thick gas-permeable membranes. The fabricated cell sheets were evaluated by histological analyses to examine the expression of corneal epithelial-specific markers. Immunohistochemical analyses showed that a putative stem cell marker, p63, a corneal epithelial differentiation maker, CK3, and a barrier function marker, Claudin-1, were expressed in the appropriate position in the cell sheets. These results suggest that the cell cartridge is effective for fabricating corneal epithelial cell sheets. Copyright © 2012 John Wiley & Sons, Ltd.

  15. Hybrid Optical Devices: The Case of the Unification of the Electrochromic Device and the Organic Solar Cell

    Directory of Open Access Journals (Sweden)

    Andre F. S. Guedes

    2016-06-01

    Full Text Available The development of Hybrid Optical Devices, using some flexible optically transparent substrate material and organic semiconductor materials, has been widely utilized by the organic electronic industry, when manufacturing new technological products. The Hybrid Optical Device is constituted by the union of the electrochromic device and the organic solar cell. The flexible organic photovoltaic solar cells, in this hybrid optical device, have been the Poly base (3-hexyl thiophene, P3HT, Phenyl-C61-butyric acid methyl ester, PCBM and Polyaniline, PANI, all being deposited in Indium Tin Oxide, ITO. In addition, the thin film, obtained by the deposition of PANI, and prepared in perchloric acid solution, has been identified through PANI-X1. In the flexible electrochromic device, the Poly base (3,4-ethylenedioxythiophene, PEDOT, has been prepared in Propylene Carbonate, PC, being deposited in Indium Tin Oxide, ITO. Also, both devices have been united by an electrolyte solution prepared with Vanadium Pentoxide, V2O5, Lithium Perchlorate, LiClO4, and Polymethylmethacrylate, PMMA. This device has been characterized through Electrical Measurements, such as UV-Vis Spectroscopy and Scanning Electron Microscopy (SEM. Thus, the result obtained through electrical measurements has demonstrated that the flexible organic photovoltaic solar cell presented the characteristic curve of standard solar cell after spin-coating and electrodeposition. Accordingly, the results obtained with optical and electrical characterization have revealed that the electrochromic device demonstrated some change in optical absorption, when subjected to some voltage difference. Moreover, the inclusion of the V2O5/PANI-X1 layer reduced the effects of degradation that this hybrid organic device caused, that is, solar irradiation. Studies on Scanning Electron Microscopy (SEM have found out that the surface of V2O5/PANI-X1 layers can be strongly conditioned by the surface morphology of the

  16. Particle compositions with a pre-selected cell internalization mode

    Science.gov (United States)

    Decuzzi, Paolo (Inventor); Ferrari, Mauro (Inventor)

    2012-01-01

    A method of formulating a particle composition having a pre-selected cell internalization mode involves selecting a target cell having surface receptors and obtaining particles that have i) surface moieties, that have an affinity for or are capable of binding to the surface receptors of the cell and ii) a preselected shape, where a surface distribution of the surface moieties on the particles and the shape of the particles are effective for the pre-selected cell internalization mode.

  17. Review of microfluidic cell culture devices for the control of gaseous microenvironments in vitro

    Science.gov (United States)

    Wu, H.-M.; Lee, T.-A.; Ko, P.-L.; Chiang, H.-J.; Peng, C.-C.; Tung, Y.-C.

    2018-04-01

    Gaseous microenvironments play important roles in various biological activities in vivo. However, it is challenging to precisely control gaseous microenvironments in vitro for cell culture due to the high diffusivity nature of gases. In recent years, microfluidics has paved the way for the development of new types of cell culture devices capable of manipulating cellular microenvironments, and provides a powerful tool for in vitro cell studies. This paper reviews recent developments of microfluidic cell culture devices for the control of gaseous microenvironments, and discusses the advantages and limitations of current devices. We conclude with suggestions for the future development of microfluidic cell culture devices for the control of gaseous microenvironments.

  18. Digital cell counting device integrated with a single-cell array.

    Directory of Open Access Journals (Sweden)

    Tatsuya Saeki

    Full Text Available In this paper, we present a novel cell counting method accomplished using a single-cell array fabricated on an image sensor, complementary metal oxide semiconductor sensor. The single-cell array was constructed using a microcavity array, which can trap up to 7,500 single cells on microcavities periodically arranged on a plane metallic substrate via the application of a negative pressure. The proposed method for cell counting is based on shadow imaging, which uses a light diffraction pattern generated by the microcavity array and trapped cells. Under illumination, the cell-occupied microcavities are visualized as shadow patterns in an image recorded by the complementary metal oxide semiconductor sensor due to light attenuation. The cell count is determined by enumerating the uniform shadow patterns created from one-on-one relationships with single cells trapped on the microcavities in digital format. In the experiment, all cell counting processes including entrapment of non-labeled HeLa cells from suspensions on the array and image acquisition of a wide-field-of-view of 30 mm(2 in 1/60 seconds were implemented in a single integrated device. As a result, the results from the digital cell counting had a linear relationship with those obtained from microscopic observation (r(2  = 0.99. This platform could be used at extremely low cell concentrations, i.e., 25-15,000 cells/mL. Our proposed system provides a simple and rapid miniaturized cell counting device for routine laboratory use.

  19. Hibiscus fiber carbon for fuel cell device material

    International Nuclear Information System (INIS)

    Nanik Indayaningsih; Anne Zulfia; Dedi Priadi; Suprapedi

    2010-01-01

    The objective of this research is carbon of hibiscus fibers for the application as basic material of fuel cell device. The carbon is made using a pyrolysis process in inert gas (nitrogen) for 1 hour at temperature of 500 °C, 700 °C and 900 °C. The X-Ray Diffractometer (XRD), Scanning Electron Microscope (SEM) and Impedance-Capacitance-Resistance-meter are used to find out the microstructure, morphology and electrical properties respectively. The results of the experiment showed that the carbon had a structure of amorphous, and as the semiconductor material the electrical conductivity was 5 x 10 -5 S.cm -1 to 4.9 x 10 -5 S.cm -1 increasing in accordance with the pyrolysis temperature. The morphology resembled to plaited mats constructed by porous fibers having width of 50 µm to 300 µm, thickness of 25 µm to 35 µm, and the porous size of 0.5 µm to 5 µm. This morphology enables carbon to be applied as a candidate for a basic material of the Proton Exchange Membrane Fuel Cell. (author)

  20. Microfabrication of plastic-PDMS microfluidic devices using polyimide release layer and selective adhesive bonding

    Science.gov (United States)

    Wang, Shuyu; Yu, Shifeng; Lu, Ming; Zuo, Lei

    2017-05-01

    In this paper, we present an improved method to bond poly(dimethylsiloxane) (PDMS) with polyimide (PI) to develop flexible substrate microfluidic devices. The PI film was separately fabricated on a silicon wafer by spin coating followed by thermal treatment to avoid surface unevenness of the flexible substrate. In this way, we could also integrate flexible substrate into standard micro-electromechanical systems (MEMS) fabrication. Meanwhile, the adhesive epoxy was selectively transferred to the PDMS microfluidic device by a stamp-and-stick method to avoid epoxy clogging the microfluidic channels. To spread out the epoxy evenly on the transferring substrate, we used superhydrophilic vanadium oxide film coated glass as the transferring substrate. After the bonding process, the flexible substrate could easily be peeled off from the rigid substrate. Contact angle measurement was used to characterize the hydrophicity of the vanadium oxide film. X-ray photoelectron spectroscopy analysis was conducted to study the surface of the epoxy. We further evaluated the bonding quality by peeling tests, which showed a maximum bonding strength of 100 kPa. By injecting with black ink, the plastic microfluidic device was confirmed to be well bonded with no leakage for a day under 1 atm. This proposed versatile method could bond the microfluidic device and plastic substrate together and be applied in the fabrication of some biosensors and lab-on-a-chip systems.

  1. Development of a framework for pneumatic device selection for lymphedema treatment

    Directory of Open Access Journals (Sweden)

    Sonja M Maul

    2009-12-01

    Full Text Available Sonja M Maul1, Julie A Devine2, Carolyn R Wincer31St. Luke’s Idaho Elks Rehabilitative Services, Boise, ID, USA; 2Center for Wound Care, Butler Memorial Hospital, Butler, PA, USA; 3Centers for Rehabilitation Services, Gibsonia, PA, USAAbstract: The results of three patients with difficult to manage leg and trunk lymphedema are reported. Patients were treated with the current standard of care: combined decongestive therapy. All three patients met obstacles in achieving independent self-care, which impeded their discharge to home care. The use of two currently available programmable pneumatic compression devices (PCDs was investigated to determine if these devices could enable these difficult-to-manage patients to meet their discharge goals. Results indicate that programmable PCDs can be effective in managing complicated cases of leg and trunk lymphedema, and that differences may exist between devices. In this trial, the device with lower applied pressures and smaller pneumatic chambers provided better tolerated treatment and overall better patient outcomes. These three case reports show that in-home use of an appropriate PCD can help patients with stage 3 and advanced stage 2 lymphedema achieve stable limb volumes with no exacerbation of lymphedema-related symptoms. Results also demonstrate the ability of patients to consistently use programmable PCDs in a home environment. The results are presented in a structured decision-making framework to aid the therapist and physician in selecting appropriate patients for home PCD lymphedema therapy, and in the selection of an appropriate PCD.Keywords: lymphedema, swelling, pneumatic, compression, flexitouch, lympha press.

  2. Optional Frame Selection Algorithm for Adaptive Symmetric Service of Augmented Reality Big Data on Smart Devices

    Directory of Open Access Journals (Sweden)

    HwiRim Byun

    2016-05-01

    Full Text Available Following recent technological advances in diverse mobile devices, including smartphones, tablets and smartwatches, in-depth studies aimed at improving the quality of augmented reality (AR are currently ongoing. Smartphones feature the essential elements of AR implementation, such as a camera, a processor and a display in a single device. As a result, additional hardware expansion for AR implementation has become unnecessary, popularizing AR technology at the user level. In the early stages, low-level AR technology was used mainly in limited fields, including simple road guides and marker-based recognition. Due to advances in AR technology, the range of usage has expanded as diverse technologies and purposes are combined. Users’ expectations of AR technology have also increased with this trend, and a high quality of service (QoS, with high-resolution, high-quality images, is now available. However, there are limitations in terms of processing speed and graphic treatment with smart devices, which, due to their small size, have inferior performance compared to the desktop environment when processing data for the implementation of high-resolution, high-quality images. This paper proposes an optional frame-selection algorithm (OFSA, which eliminates the unnecessary work involved with redundant frames during rendering for adaptive symmetric service of augmented reality big data on smart devices. Moreover, the memory read-write delay of the internally-operating OFSA, is minimized by adding an adaptive operation function. It is possible to provide adaptive common AR images at an improved frame rate in heterogeneous smart devices with different levels of performance.

  3. Repeatability and interdevice reliability of two portable color selection devices in matching and measuring tooth color.

    Science.gov (United States)

    Lagouvardos, Panagiotis E; Fougia, Aggeliki G; Diamantopoulou, Sofia A; Polyzois, Gregory L

    2009-01-01

    There is a need to know how shade selection devices perform in matching and measuring tooth color, since these functions are usually evaluated independently and may present significant discrepancies. The purpose of this study was to evaluate 2 devices which offer both functions to test the null hypothesis that they present no differences in their repeatability and interdevice reliability relating to the 2 functions. Thirty-one extracted anterior human teeth were measured twice, with each of the devices (ShadeEye NCC and VITA EasyShade), by one investigator experienced and calibrated with both devices. L*a*b* values and shade matches to VITA Classical and Vitapan 3D-Master shade guide systems were determined for all teeth. Paired t tests and intraclass correlation coefficients (ICCs) were used to statistically analyze the data (alpha=.05). The results showed that L*a*b* values with VITA EasyShade were significantly higher than those with ShadeEye NCC (PL*a*b* parameters, while interdevice matching reliability ranged from 0.189 to 0.430, with no significant differences between shade systems (P>.05). All tooth color parameters were higher with the VITA EasyShade device. Measuring repeatability of the VITA EasyShade was higher than the ShadeEye NCC only for the L* parameter. Matching repeatability of the ShadeEye NCC was higher than the VITA EasyShade for the VITA Classical system. Interdevice measuring reliabilities were not different for the color parameters, but matching reliability of the VITA Classical system was higher than that of the Vitapan 3D-Master.

  4. Bring-Your-Own-Device: Turning Cell Phones into Forces for Good

    Science.gov (United States)

    Imazeki, Jennifer

    2014-01-01

    Over the last few years, classroom response systems (or "clickers") have become increasingly common. Although most systems require students to use a standalone handheld device, bring-your-own-device (BYOD) systems allow students to use devices they already own (e.g., a cell phone, tablet or laptop) to submit responses via text message or…

  5. Role of the Selective Contacts in the Performance of Lead Halide Perovskite Solar Cells.

    Science.gov (United States)

    Juarez-Perez, Emilio J; Wuβler, Michael; Fabregat-Santiago, Francisco; Lakus-Wollny, Kerstin; Mankel, Eric; Mayer, Thomas; Jaegermann, Wolfram; Mora-Sero, Ivan

    2014-02-20

    The effect of electron- and hole-selective contacts in the final cell performance of hybrid lead halide perovskite, CH3NH3PbI3, solar cells has been systematically analyzed by impedance spectroscopy. Complete cells with compact TiO2 and spiro-OMeTAD as electron- and hole-selective contacts have been compared with incomplete cells without one or both selective contacts to highlight the specific role of each contact. It has been described how selective contacts contribute to enhance the cell FF and how the hole-selective contact is mainly responsible for the high Voc in this kind of device. We have determined that the recombination rate is mainly governed by the selective contacts. This fact has important implication for the future optimization of perovskite solar cells. Finally, we have developed a method to analyze the results obtained, and it has been applied for three different electron-selecting materials: TiO2, ZnO, and CdS.

  6. Nylon-3 polymers that enable selective culture of endothelial cells.

    Science.gov (United States)

    Liu, Runhui; Chen, Xinyu; Gellman, Samuel H; Masters, Kristyn S

    2013-11-06

    Substrates that selectively encourage the growth of specific cell types are valuable for the engineering of complex tissues. Some cell-selective peptides have been identified from extracellular matrix proteins; these peptides have proven useful for biomaterials-based approaches to tissue repair or regeneration. However, there are very few examples of synthetic materials that display selectivity in supporting cell growth. We describe nylon-3 polymers that support in vitro culture of endothelial cells but do not support the culture of smooth muscle cells or fibroblasts. These materials may be promising for vascular biomaterials applications.

  7. Selection of D-Alanine-Tolerant Rice Cells

    OpenAIRE

    Hisashi, Manabe; Koji, Ohira; Aizu Junior College of Fukushima Prefecture; Department of Agricultural Chemistry, Faculty of Agriculture, Tohoku University

    1984-01-01

    By repeating subculture of rice cells (parent cells) in a D-alanine containing medium, we could select rice cells which grew well in the D-alanine medium. The D-alanine-tolerant cells absorbed a fairly small amount of D-alanine from the medium and did not accumulate much D-alanine in the cells. Aggregation of D-alanine-tolerant cells was greater than that of parent cells. D-Alanine metabolism of D-alanine.-tolerant cells did not increase in comparison with parent cells.

  8. NIR-Selective electrochromic heteromaterial frameworks: a platform to understand mesoscale transport phenomena in solid-state electrochemical devices

    Energy Technology Data Exchange (ETDEWEB)

    Williams, TE; Chang, CM; Rosen, EL; Garcia, G; Runnerstrom, EL; Williams, BL; Koo, B; Buonsanti, R; Milliron, DJ; Helms, BA

    2014-01-01

    We report here the first solid-state, NIR-selective electrochromic devices. Critical to device performance is the arrangement of nanocrystal-derived electrodes into heteromaterial frameworks, where hierarchically porous ITO nanocrystal active layers are infiltrated by an ion-conducting polymer electrolyte with mesoscale periodicity. Enhanced coloration efficiency and transport are realized over unarchitectured electrodes in devices, paving the way towards new smart windows technologies.

  9. Nondestructive method for detecting defects in photodetector and solar cell devices

    Science.gov (United States)

    Not Available

    The invention described herein is a method for locating semiconductor device defects and for measuring the internal resistance of such devices by making use of the intrinsic distributed resistance nature of the devices. The method provides for forward-biasing a solar cell or other device while it is scanning with an optical spot. The forward-biasing is achieved with either an illuminator light source or an external current source.

  10. A co-culture device with a tunable stiffness to understand combinatorial cell-cell and cell-matrix interactions.

    Science.gov (United States)

    Rao, Nikhil; Grover, Gregory N; Vincent, Ludovic G; Evans, Samantha C; Choi, Yu Suk; Spencer, Katrina H; Hui, Elliot E; Engler, Adam J; Christman, Karen L

    2013-11-01

    Cell behavior on 2-D in vitro cultures is continually being improved to better mimic in vivo physiological conditions by combining niche cues including multiple cell types and substrate stiffness, which are well known to impact cell phenotype. However, no system exists in which a user can systematically examine cell behavior on a substrate with a specific stiffness (elastic modulus) in culture with a different cell type, while maintaining distinct cell populations. We demonstrate the modification of a silicon reconfigurable co-culture system with a covalently linked hydrogel of user-defined stiffness. This device allows the user to control whether two separate cell populations are in contact with each other or only experience paracrine interactions on substrates of controllable stiffness. To illustrate the utility of this device, we examined the role of substrate stiffness combined with myoblast co-culture on adipose derived stem cell (ASC) differentiation and found that the presence of myoblasts and a 10 kPa substrate stiffness increased ASC myogenesis versus co-culture on stiff substrates. As this example highlights, this technology better controls the in vitro microenvironment, allowing the user to develop a more thorough understanding of the combined effects of cell-cell and cell-matrix interactions.

  11. High-Throughput Selective Capture of Single Circulating Tumor Cells by Dielectrophoresis at a Wireless Electrode Array.

    Science.gov (United States)

    Li, Min; Anand, Robbyn K

    2017-07-05

    We demonstrate continuous high-throughput selective capture of circulating tumor cells by dielectrophoresis at arrays of wireless electrodes (bipolar electrodes, BPEs). The use of BPEs removes the requirement of ohmic contact to individual array elements, thus enabling otherwise unattainable device formats. Capacitive charging of the electrical double layer at opposing ends of each BPE allows an AC electric field to be transmitted across the entire device. Here, two such designs are described and evaluated. In the first design, BPEs interconnect parallel microchannels. Pockets extruding from either side of the microchannels volumetrically control the number of cells captured at each BPE tip and enhance trapping. High-fidelity single-cell capture was achieved when the pocket dimensions were matched to those of the cells. A second, open design allows many non-targeted cells to pass through. These devices enable high-throughput capture of rare cells and single-cell analysis.

  12. Cost-Based Design and Selection of Point Absorber Devices for the Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    Vincenzo Piscopo

    2018-04-01

    Full Text Available Sea wave energy is one of the most promising renewable sources, even if relevant technology is not mature enough for the global energy market and is not yet competitive if compared with solar, wind and tidal current devices. Particularly, among the variety of wave energy converters developed in the last decade, heaving point absorbers represent one of the most feasible and studied technologies, as shown by the small-scale testing and full-scale prototypes, deployed in the last years throughout the world. Nevertheless, the need for further reduction of the energy production costs requires a specialized design of wave energy converters, accounting for the restraints provided by the power take-off unit and the device operational profile. Hence, actual analysis focuses on a new cost-based design procedure for heaving point absorbers. The device is equipped with a floating buoy with an optional fully submerged mass connected, by means of a tensioned line, to the power take-off unit. It consists of a permanent magnet linear generator, lying on the seabed and equipped with a gravity-based foundation. The proposed procedure is applied to several candidate deployment sites located in the Mediterranean Sea; the incidence of the power take-off restraint and the converter operational profile is fully investigated and some recommendations for preliminary design of wave energy converter devices are provided. Current results show that there is wide scope to make the wave energy sector more competitive on the international market, by properly selecting the main design parameters of point absorbers, on the basis of met-ocean conditions at the deployment site.

  13. Combinational Effect of Cell Adhesion Biomolecules and Their Immobilized Polymer Property to Enhance Cell-Selective Adhesion

    Directory of Open Access Journals (Sweden)

    Rio Kurimoto

    2016-01-01

    Full Text Available Although surface immobilization of medical devices with bioactive molecules is one of the most widely used strategies to improve biocompatibility, the physicochemical properties of the biomaterials significantly impact the activity of the immobilized molecules. Herein we investigate the combinational effects of cell-selective biomolecules and the hydrophobicity/hydrophilicity of the polymeric substrate on selective adhesion of endothelial cells (ECs, fibroblasts (FBs, and smooth muscle cells (SMCs. To control the polymeric substrate, biomolecules are immobilized on thermoresponsive poly(N-isopropylacrylamide-co-2-carboxyisopropylacrylamide (poly(NIPAAm-co-CIPAAm-grafted glass surfaces. By switching the molecular conformation of the biomolecule-immobilized polymers, the cell-selective adhesion performances are evaluated. In case of RGDS (Arg-Gly-Asp-Ser peptide-immobilized surfaces, all cell types adhere well regardless of the surface hydrophobicity. On the other hand, a tri-Arg-immobilized surface exhibits FB-selectivity when the surface is hydrophilic. Additionally, a tri-Ile-immobilized surface exhibits EC-selective cell adhesion when the surface is hydrophobic. We believe that the proposed concept, which is used to investigate the biomolecule-immobilized surface combination, is important to produce new biomaterials, which are highly demanded for medical implants and tissue engineering.

  14. Designing of a Si-MEMS device with an integrated skeletal muscle cell-based bio-actuator.

    Science.gov (United States)

    Fujita, Hideaki; Van Dau, Thanh; Shimizu, Kazunori; Hatsuda, Ranko; Sugiyama, Susumu; Nagamori, Eiji

    2011-02-01

    With the aim of designing a mechanical drug delivery system involving a bio-actuator, we fabricated a Micro Electro Mechanical Systems (MEMS) device that can be driven through contraction of skeletal muscle cells. The device is composed of a Si-MEMS with springs and ratchets, UV-crosslinked collagen film for cell attachment, and C2C12 muscle cells. The Si-MEMS device is 600 μm x 1000 μm in size and the width of the collagen film is 250 ~ 350 μm, which may allow the device to go through small blood vessels. To position the collagen film on the MEMS device, a thermo-sensitive polymer was used as the sacrifice-layer which was selectively removed with O₂ plasma at the positions where the collagen film was glued. The C2C12 myoblasts were seeded on the collagen film, where they proliferated and formed myotubes after induction of differentiation. When C2C12 myotubes were stimulated with electric pulses, contraction of the collagen film-C2C12 myotube complex was observed. When the edge of the Si-MEMS device was observed, displacement of ~8 μm was observed, demonstrating the possibility of locomotive movement when the device is placed on a track of adequate width. Here, we propose that the C2C12-collagen film complex is a new generation actuator for MEMS devices that utilize glucose as fuel, which will be useful in environments in which glucose is abundant such as inside a blood vessel.

  15. Integrated microfluidic device for single-cell trapping and spectroscopy

    KAUST Repository

    Liberale, Carlo

    2013-02-13

    Optofluidic microsystems are key components towards lab-on-a-chip devices for manipulation and analysis of biological specimens. In particular, the integration of optical tweezers (OT) in these devices allows stable sample trapping, while making available mechanical, chemical and spectroscopic analyses.

  16. Spatially selecting a single cell for lysis using light-induced electric fields.

    Science.gov (United States)

    Witte, Christian; Kremer, Clemens; Chanasakulniyom, Mayuree; Reboud, Julien; Wilson, Rab; Cooper, Jonathan M; Neale, Steven L

    2014-08-13

    An optoelectronic tweezing (OET) device, within an integrated microfluidic channel, is used to precisely select single cells for lysis among dense populations. Cells to be lysed are exposed to higher electrical fields than their neighbours by illuminating a photoconductive film underneath them. Using beam spot sizes as low as 2.5 μm, 100% lysis efficiency is reached in <1 min allowing the targeted lysis of cells. © 2014 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Opportunities for inhaler device selection in elderly patients with asthma or COPD

    Directory of Open Access Journals (Sweden)

    Barrons R

    2015-12-01

    Full Text Available Robert Barrons,1 James Wheeler,2 J Andrew Woods1 1Wingate University School of Pharmacy, Wingate, NC, USA; 2University of Tennessee Health Science Center, Nashville, TN, USA Abstract: An anticipated surge in the elderly population will be accompanied by a rise in aging patients with asthma or COPD. Clinician selection of inhalers needs to address the unique challenges to elderly patients. These challenges to the use of inhalers include diminished physical and cognitive abilities, as well as cost reimbursement issues associated with polypharmacy and the Medicare gap. Clinicians should consider patient preferences for an inhaler device that provides ease of administration, and addresses conveniences such as portability, visual, and auditory indicators of dosing completion. The addition of spacer devices resolves hand-breath coordination difficulty with pressurized metered dose inhalers, but reduces overall inhaler convenience. Soft mist inhalers (Respimat® improve ease of administration, but use may be limited by cost and formulary availability. Multiple dose dry powder inhalers provide convenience and simplified use by requiring only one to two steps prior to administration, but concerns of peak inspiratory flow requirements remain among patients with advanced age and severity of COPD. If unaddressed, these challenges to inhaler selection contribute to inappropriate use of inhalers in 41% to 69% of patients, accompanied by at least 51% non-adherence to treatment. Clinicians must first avail themselves of reputable educational resources regarding new inhaler developments and administration, for competent patient instruction. Patient education should include a checklist of inhaler technique, with physical demonstration of each device by the patient and provider. Device demonstration significantly improves inhaler technique and identifies the need for nebulization therapy. Clinician and patient knowledge of available inhalers and their

  18. Ion-Selective Detection with Glass Nanopipette for Living Cells

    Science.gov (United States)

    Takami, T.; Son, J. W.; Kang, E. J.; Deng, X. L.; Kawai, T.; Lee, S.-W.; Park, B. H.

    2013-05-01

    We developed a method to probe local ion concentration with glass nanopipette in which poly(vinyl chloride) membrane containing ionophore for separate ion detection is prepared. Here we demonstrate how ion-selective detections are available for living cells such as HeLa cell, rat vascular myocyte, and neuron cell.

  19. A novel LTCC electrochemical cell construction and characterization: a detection compartment for portable devices.

    Science.gov (United States)

    Pesquero, Naira Canevarolo; Gongora-Rubio, Mário Ricardo; Yamanaka, Hideko

    2013-08-07

    In this work we described for the first time the construction of a 25 μL electrochemical cell from low temperature co-fired ceramic (LTCC) material and carbon screen-printed electrode applicable in portable devices. Firstly, a carbon screen-printed electrode was prepared and characterized by cyclic voltammetry and scanning electron microscopy. Afterwards carbon polymeric film and metal pastes were dropped into the LTCC cell cavities in order to determine the device electrodes, and this arrangement was also electrochemically characterized. The great advantage of this promising device is the simple construction method and its widespread applicability in reusable portable devices.

  20. Device for the selective positioning of a component on a tube plate

    International Nuclear Information System (INIS)

    1974-01-01

    The invention relates to a device for the selective positioning of a component on a tube plate. It particularly applies to the positioning of a guide tube head successively opposite all the tubes of the tube bundle of a nuclear reactor steam generator. The large number of tubes in the tube bundle of the steam generator in a pressure water nuclear power station must be checked periodically for any likely corrosion. This check is effected with a Foucault current probe which is inserted in each tube in turn and is connected to a probe signal processing unit. The probe is placed in a flexible guide tube brought in turn in front of each tube of the bundle to be checked. The invention concerns a device to move the opening of a tube guide for a Foucault current detector over the entire surface of the tube plate, thereby providing access to all the tubes whilst limiting the interventions to a single positioning and a single withdrawal of the apparatus for testing all the bundle. Between the two interventions at the beginning and end of the operation, all displacements are remote controlled from outside the dangerous radioacive area [fr

  1. Formation of biodegradable microcapsules utilizing 3D, selectively surface-modified PDMS microfluidic devices.

    Science.gov (United States)

    Liao, Chung-Yu; Su, Yu-Chuan

    2010-02-01

    We have successfully demonstrated the formation of biodegradable microcapsules utilizing PDMS double-emulsification devices. Specially designed 3D PDMS microchannels with surfaces selectively modified by a self-aligned photografting process are employed to generate monodisperse water-in-organic-solvent-in-water (W/O/W) emulsions in a controlled manner. Mainly by varying the outer and inner fluid flow-rates, the dimensions of resulting double emulsions can be adjusted as desired. Meanwhile, biodegradable materials are dissolved in the middle organic solvent (in this work ethyl acetate is used), and solidified into microcapsules once the solvent is extracted. In the prototype demonstration, microcapsules made up of poly(L-lactic acid), trilaurin, and phosphocholine were successfully fabricated. In addition, it was also demonstrated that gamma-Fe(2)O(3) nanoparticles can be simultaneously embedded into the microcapsules, which consequently become responsive to electromagnetic stimulation. As such, the presented PDMS microfluidic devices could potentially serve as versatile encapsulation apparatus, and the fabricated biodegradable microcapsules could function as controlled delivery systems, which are desired for a variety of biological and pharmaceutical applications.

  2. Mode-selective vibrational modulation of charge transport in organic electronic devices

    KAUST Repository

    Bakulin, Artem A.

    2015-08-06

    The soft character of organic materials leads to strong coupling between molecular, nuclear and electronic dynamics. This coupling opens the way to influence charge transport in organic electronic devices by exciting molecular vibrational motions. However, despite encouraging theoretical predictions, experimental realization of such approach has remained elusive. Here we demonstrate experimentally that photoconductivity in a model organic optoelectronic device can be modulated by the selective excitation of molecular vibrations. Using an ultrafast infrared laser source to create a coherent superposition of vibrational motions in a pentacene/C60 photoresistor, we observe that excitation of certain modes in the 1,500–1,700 cm−1 region leads to photocurrent enhancement. Excited vibrations affect predominantly trapped carriers. The effect depends on the nature of the vibration and its mode-specific character can be well described by the vibrational modulation of intermolecular electronic couplings. This presents a new tool for studying electron–phonon coupling and charge dynamics in (bio)molecular materials.

  3. T cell depleted haploidentical transplantation: positive selection

    Directory of Open Access Journals (Sweden)

    Franco Aversa

    2011-06-01

    Full Text Available Interest in mismatched transplantation arises from the fact that a suitable one-haplotype mismatched donor is immediately available for virtually all patients, particularly for those who urgently need an allogenic transplant. Work on one haplotype-mismatched transplants has been proceeding for over 20 years all over the world and novel transplant techniques have been developed. Some centres have focused on the conditioning regimens and post transplant immune suppression; others have concentrated on manipulating the graft which may be a megadose of extensively T celldepleted or unmanipulated progenitor cells. Excellent engraftment rates are associated with a very low incidence of acute and chronic GVHD and regimen-related mortality even in patients who are over 50 years old. Overall, event-free survival and transplant-related mortality compare favourably with reports on transplants from sources of stem cells other than the matched sibling.

  4. Treatment selection for tonsillar squamous cell carcinoma

    Directory of Open Access Journals (Sweden)

    Yao-Yuan Kuo

    2013-04-01

    Conclusion: Both primary surgery and RT/CRT organ preservation are effective treatments for tonsillar SCC. Single modality treatment, either surgery or RT/CRT, can typically be provided for stage I–II diseases. Although RT/CRT organ preservation is used more frequently for stage III–IV tonsillar SCC in recent years, primary surgery combined with adjuvant therapy still achieves equivalent outcomes. Multidisciplinary pretreatment counseling and the facilities and personnel available are therefore important for decision-making. In addition, if RT/CRT organ preservation is selected as the primary treatment, tumor tonsillectomy is not indicated.

  5. Selective uptake of boronophenylalanine by glioma stem/progenitor cells

    International Nuclear Information System (INIS)

    Sun, Ting; Zhou, Youxin; Xie, Xueshun; Chen, Guilin; Li, Bin; Wei, Yongxin; Chen, Jinming; Huang, Qiang; Du, Ziwei

    2012-01-01

    The success of boron neutron capture therapy (BNCT) depends on the amount of boron in cells and the tumor/blood and tumor/(normal tissue) boron concentration ratios. For the first time, measurements of boron uptake in both stem/progenitor and differentiated glioma cells were performed along with measurements of boron biodistribution in suitable animal models. In glioma stem/progenitor cells, the selective accumulation of boronophenylalanine (BPA) was lower, and retention of boron after BPA removal was longer than in differentiated glioma cells in vitro. However, boron biodistribution was not statistically significantly different in mice with xenografts. - Highlights: ► Uptake of BPA was analyzed in stem/progenitor and differentiated glioma cells. ► Selective accumulation of BPA was lower in glioma stem/progenitor cells. ► Retention of boron after BPA removal was longer in glioma stem/progenitor cells. ► Boron biodistribution was not statistically different in mice with xenografts.

  6. Measurement-device-independent quantum key distribution with multiple crystal heralded source with post-selection

    Science.gov (United States)

    Chen, Dong; Shang-Hong, Zhao; MengYi, Deng

    2018-03-01

    The multiple crystal heralded source with post-selection (MHPS), originally introduced to improve the single-photon character of the heralded source, has specific applications for quantum information protocols. In this paper, by combining decoy-state measurement-device-independent quantum key distribution (MDI-QKD) with spontaneous parametric downconversion process, we present a modified MDI-QKD scheme with MHPS where two architectures are proposed corresponding to symmetric scheme and asymmetric scheme. The symmetric scheme, which linked by photon switches in a log-tree structure, is adopted to overcome the limitation of the current low efficiency of m-to-1 optical switches. The asymmetric scheme, which shows a chained structure, is used to cope with the scalability issue with increase in the number of crystals suffered in symmetric scheme. The numerical simulations show that our modified scheme has apparent advances both in transmission distance and key generation rate compared to the original MDI-QKD with weak coherent source and traditional heralded source with post-selection. Furthermore, the recent advances in integrated photonics suggest that if built into a single chip, the MHPS might be a practical alternative source in quantum key distribution tasks requiring single photons to work.

  7. Photo-thermal hybrid module with photovoltaic cells and thermoelectric devices for space application

    Energy Technology Data Exchange (ETDEWEB)

    Tsukamoto, Moriaki; Hayashibara, Mitsuo

    1988-11-30

    Based upon the assumption that higher efficeint thermoelectric device will come in practice, a feasibility study was carried out to investigate the performance of photo-thermal hybrid module for space application. The photo-thermal hybrid modules consist of laminate of photovoltaic cells, thermoelectric devices and radiators. Solar energies collected are converted to the power generation by the photovoltaic cells and to heat them to the moderate temperature level, and then the thermoelectric devices generate the electric power, utilizing the temperature difference of thermoelectric devices between the junction surface with the photovoltaic cells (high temperature side) and one with the radiators (low temperature side). As an experimental result on the photo-thermal hybrid module which was constituted of the combination of a GaAs photovoltaic cell and a BiTe thermoelectric device, the hybrid module was able to have higher efficiency than a concentration type GaAs system. The photo-thermal arrays for space application with higher efficiency and lower specific weight might be realized, when a high performance thermoelectric device, such as a FeSi thermoelectric device, the performance of which is able to expect to be one digit higher than a BiTe thermoelectric device, is developed. 4 references, 10 figures, 1 table.

  8. An agar gel membrane-PDMS hybrid microfluidic device for long term single cell dynamic study.

    Science.gov (United States)

    Wong, Ieong; Atsumi, Shota; Huang, Wei-Chih; Wu, Tung-Yun; Hanai, Taizo; Lam, Miu-Ling; Tang, Ping; Yang, Jian; Liao, James C; Ho, Chih-Ming

    2010-10-21

    Significance of single cell measurements stems from the substantial temporal fluctuations and cell-cell variability possessed by individual cells. A major difficulty in monitoring surface non-adherent cells such as bacteria and yeast is that these cells tend to aggregate into clumps during growth, obstructing the tracking or identification of single-cells over long time periods. Here, we developed a microfluidic platform for long term single-cell tracking and cultivation with continuous media refreshing and dynamic chemical perturbation capability. The design highlights a simple device-assembly process between PDMS microchannel and agar membrane through conformal contact, and can be easily adapted by microbiologists for their routine laboratory use. The device confines cell growth in monolayer between an agar membrane and a glass surface. Efficient nutrient diffusion through the membrane and reliable temperature maintenance provide optimal growth condition for the cells, which exhibited fast exponential growth and constant distribution of cell sizes. More than 24 h of single-cell tracking was demonstrated on a transcription-metabolism integrated synthetic biological model, the gene-metabolic oscillator. Single cell morphology study under alcohol toxicity allowed us to discover and characterize cell filamentation exhibited by different E. coli isobutanol tolerant strains. We believe this novel device will bring new capabilities to quantitative microbiology, providing a versatile platform for single cell dynamic studies.

  9. Potential of PEDOT:PSS as a hole selective front contact for silicon heterojunction solar cells.

    Science.gov (United States)

    Jäckle, Sara; Liebhaber, Martin; Gersmann, Clemens; Mews, Mathias; Jäger, Klaus; Christiansen, Silke; Lips, Klaus

    2017-05-19

    We show that the highly conductive polymer poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) can successfully be applied as a hole selective front contact in silicon heterojunction (SHJ) solar cells. In combination with a superior electron selective heterojunction back contact based on amorphous silicon (a-Si), mono-crystalline n-type silicon (c-Si) solar cells reach power conversion efficiencies up to 14.8% and high open-circuit voltages exceeding 660 mV. Since in the PEDOT:PSS/c-Si/a-Si solar cell the inferior hybrid junction is determining the electrical device performance we are capable of assessing the recombination velocity (v I ) at the PEDOT:PSS/c-Si interface. An estimated v I of ~400 cm/s demonstrates, that while PEDOT:PSS shows an excellent selectivity on n-type c-Si, the passivation quality provided by the formation of a native oxide at the c-Si surface restricts the performance of the hybrid junction. Furthermore, by comparing the measured external quantum efficiency with optical simulations, we quantify the losses due to parasitic absorption of PEDOT:PSS and reflection of the device layer stack. By pointing out ways to better passivate the hybrid interface and to increase the photocurrent we discuss the full potential of PEDOT:PSS as a front contact in SHJ solar cells.

  10. Non-Destructive Detection and Separation of Radiation Damaged Cells in Miniaturized, Inexpensive Device Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Our objective is to develop and demonstrate a novel microfluidic device for non-destructive identification, sorting and counting of radiation damaged cells. A major...

  11. Peptide fibrils with altered stability, activity, and cell selectivity.

    Science.gov (United States)

    Chen, Long; Liang, Jun F

    2013-07-08

    Peptides have some unique and superior features compared to proteins. However, the use of peptides as therapeutics is hampered by their low stability and cell selectivity. In this study, a new lytic peptide (CL-1, FLGALFRALSRLL) was constructed. Under the physiological condition, peptide CL-1 self-assembled into dynamically stable aggregates with fibrils-like structures. Aggregated CL-1 demonstrated dramatically altered activity and stability in comparison with single molecule CL-1 and other lytic peptides: when incubated with cocultured bacteria and tissue cells, CL-1 aggregates killed bacteria selectively but spared cocultured human cells; CL-1 aggregates were kept intact in human serum for more than five hours. Peptide-cell interaction studies performed on lipid monolayers and live human tissue cells revealed that in comparison with monomeric CL-1, aggregated CL-1 had decreased cell affinity and membrane insertion capability on tissue cells. A dynamic process involving aggregate dissociation and rearrangement seemed to be an essential step for membrane bound CL-1 aggregates to realize its cytotoxicity to tissue cells. Our study suggests that peptide aggregation could be as important as the charge and secondary structure of a peptide in affecting peptide-cell interactions. Controlling peptide self-assembly represents a new way to increase the stability and cell selectivity of bioactive peptides for wide biomedical applications.

  12. Soft fibrin gels promote selection and growth of tumorigenic cells

    Science.gov (United States)

    Liu, Jing; Tan, Youhua; Zhang, Huafeng; Zhang, Yi; Xu, Pingwei; Chen, Junwei; Poh, Yeh-Chuin; Tang, Ke; Wang, Ning; Huang, Bo

    2012-08-01

    The identification of stem-cell-like cancer cells through conventional methods that depend on stem cell markers is often unreliable. We developed a mechanical method for selecting tumorigenic cells by culturing single cancer cells in fibrin matrices of ~100 Pa in stiffness. When cultured within these gels, primary human cancer cells or single cancer cells from mouse or human cancer cell lines grew within a few days into individual round colonies that resembled embryonic stem cell colonies. Subcutaneous or intravenous injection of 10 or 100 fibrin-cultured cells in syngeneic or severe combined immunodeficiency mice led to the formation of solid tumours at the site of injection or at the distant lung organ much more efficiently than control cancer cells selected using conventional surface marker methods or cultured on conventional rigid dishes or on soft gels. Remarkably, as few as ten such cells were able to survive and form tumours in the lungs of wild-type non-syngeneic mice.

  13. Feasibility study of using a Zener diode as the selection device for bipolar RRAM and WORM memory arrays

    International Nuclear Information System (INIS)

    Li, Yingtao; Fu, Liping; Tao, Chunlan; Jiang, Xinyu; Sun, Pengxiao

    2014-01-01

    Cross-bar arrays are usually used for the high density application of resistive random access memory (RRAM) devices. However, cross-talk interference limits an increase in the integration density. In this paper, the Zener diode is proposed as a selection device to suppress the sneak current in bipolar RRAM arrays. Measurement results show that the Zener diode can act as a good selection device, and the sneak current can be effectively suppressed. The readout margin is sufficiently improved compared to that obtained without the selection device. Due to the improvement for the reading disturbance, the size of the cross-bar array can be enhanced to more than 10 3  × 10 3 . Furthermore, the possibility of using a write-once-read-many-times (WORM) cross-bar array is also demonstrated by connecting the Zener diode and the bipolar RRAM in series. These results strongly suggest that using a Zener diode as a selection device opens up great opportunities to realize high density bipolar RRAM arrays. (paper)

  14. Assessment of Selected Parameters of the Automatic Scarification Device as an Example of a Device for Sustainable Forest Management

    Directory of Open Access Journals (Sweden)

    Ryszard Tadeusiewicz

    2017-12-01

    Full Text Available Due to technological progress in forestry, seedlings with covered root systems—especially those grown in container nurseries—have become increasingly important in forest nursery production. One the trees that is most commonly grown this way is the common oak (Quercus robur L.. For an acorn to be sown in a container, it is necessary to remove its upper part during mechanical scarification, and evaluate its sowing suitability. At present, this is mainly done manually and by visual assessment. The low effectiveness of this method of acorn preparation has encouraged a search for unconventional solutions. One of them is the use of an automated device that consists of a computer vision-based module. For economic reasons related to the cost of growing seedlings in container nurseries, it is beneficial to minimize the contribution of unhealthy seeds. The maximum accuracy, which is understood as the number of correct seed diagnoses relative to the total number of seeds being assessed, was adopted as a criterion for choosing a separation threshold. According to the method proposed, the intensity and red components of the images of scarified acorns facilitated the best results in terms of the materials examined during the experiment. On average, a 10% inaccuracy of separation was observed. A secondary outcome of the presented research is an evaluation of the ergonomic parameters of the user interface that is attached to the unit controlling the device when it is running in its autonomous operation mode.

  15. Architecture for user preference-based dynamic service selection in grid infrastructure using mobile devices for SMMEs

    CSIR Research Space (South Africa)

    Manqele, S

    2012-11-01

    Full Text Available Annual Conference on World Wide Web Applications, Durban, South Africa, 7-9 November 2012 Architecture for user preference-based dynamic service selection in grid infrastructure using mobile devices for SMMEs S. Manqele1, N.Dlodlo1, M. Adigun2, S... of available services in the Grid environment. Solution: This research proposes an architecture for user preference-based dynamic service selection in a grid infrastructure. In the architecture, using mobile devices, a grid user (SMME) makes a request for a...

  16. Organic solar cells theory, experiment, and device simulation

    CERN Document Server

    Tress, Wolfgang

    2014-01-01

    This book covers in a textbook-like fashion the basics or organic solar cells, addressing the limits of photovoltaic energy conversion and giving a well-illustrated introduction to molecular electronics with focus on the working principle and characterization of organic solar cells. Further chapters based on the author's dissertation focus on the electrical processes in organic solar cells by presenting a detailed drift-diffusion approach to describe exciton separation and charge-carrier transport and extraction. The results, although elaborated on small-molecule solar cells and with focus on

  17. Endothelial Cell Culture Under Perfusion On A Polyester-Toner Microfluidic Device.

    Science.gov (United States)

    Urbaczek, Ana Carolina; Leão, Paulo Augusto Gomes Carneiro; Souza, Fayene Zeferino Ribeiro de; Afonso, Ana; Vieira Alberice, Juliana; Cappelini, Luciana Teresa Dias; Carlos, Iracilda Zeppone; Carrilho, Emanuel

    2017-09-05

    This study presents an inexpensive and easy way to produce a microfluidic device that mimics a blood vessel, serving as a start point for cell culture under perfusion, cardiovascular research, and toxicological studies. Endpoint assays (i.e., MTT reduction and NO assays) were used and revealed that the components making up the microchip, which is made of polyester and toner (PT), did not induce cell death or nitric oxide (NO) production. Applying oxygen plasma and fibronectin improved the adhesion and proliferation endothelial cell along the microchannel. As expected, these treatments showed an increase in vascular endothelial growth factor (VEGF-A) concentration profiles, which is correlated with adherence and cell proliferation, thus promoting endothelialization of the device for neovascularization. Regardless the simplicity of the device, our "vein-on-a-chip" mimetic has a potential to serve as a powerful tool for those that demand a rapid microfabrication method in cell biology or organ-on-a-chip research.

  18. A novel modular device for 3-D bone cell culture and non-destructive cell analysis.

    Science.gov (United States)

    Kunz, Friederike; Bergemann, Claudia; Klinkenberg, Ernst-Dieter; Weidmann, Arne; Lange, Regina; Beck, Ulrich; Nebe, J Barbara

    2010-09-01

    Synthetic materials have emerged as bone substitutes for filling bone defects of critical sizes. Because bone healing requires a mechanically resistant matrix (scaffold) attractive to osteogenic cells and must allow revascularization for nutrient and oxygen supply, scaffold-based strategies focus on the further development of chemical and physical qualities of the material. Cellular ingrowth towards the scaffold center is critical; therefore selective information from inner regions, in particular from the central part, is essential. In this paper we introduce a novel modular in vitro system for three-dimensional (3-D) in vitro bone cell cultures. This 3-D system is developed exclusively for in vitro research purposes, with special emphasis on the geometrical scaffold design (pore size, pore design). The system is composed of a stack of titanium slices which are mounted on a clamp and which enable the separate monitoring of cell growth patterns on every single slice of the slide stack. In this way we are able to gain selective information about the regulation of the cell physiology in the inner part of the 3-D construct which can be used for the development of an optimized scaffold design for orthopedic implants. 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  19. Developing robust, hydrogel-based, nanofiber-enabled encapsulation devices (NEEDs) for cell therapies.

    Science.gov (United States)

    An, Duo; Ji, Yewei; Chiu, Alan; Lu, Yen-Chun; Song, Wei; Zhai, Lei; Qi, Ling; Luo, Dan; Ma, Minglin

    2015-01-01

    Cell encapsulation holds enormous potential to treat a number of hormone deficient diseases and endocrine disorders. We report a simple and universal approach to fabricate robust, hydrogel-based, nanofiber-enabled encapsulation devices (NEEDs) with macroscopic dimensions. In this design, we take advantage of the well-known capillary action that holds wetting liquid in porous media. By impregnating the highly porous electrospun nanofiber membranes of pre-made tubular or planar devices with hydrogel precursor solutions and subsequent crosslinking, we obtained various nanofiber-enabled hydrogel devices. This approach is broadly applicable and does not alter the water content or the intrinsic chemistry of the hydrogels. The devices retained the properties of both the hydrogel (e.g. the biocompatibility) and the nanofibers (e.g. the mechanical robustness). The facile mass transfer was confirmed by encapsulation and culture of different types of cells. Additional compartmentalization of the devices enabled paracrine cell co-cultures in single implantable devices. Lastly, we provided a proof-of-concept study on potential therapeutic applications of the devices by encapsulating and delivering rat pancreatic islets into chemically-induced diabetic mice. The diabetes was corrected for the duration of the experiment (8 weeks) before the implants were retrieved. The retrieved devices showed minimal fibrosis and as expected, live and functional islets were observed within the devices. This study suggests that the design concept of NEEDs may potentially help to overcome some of the challenges in the cell encapsulation field and therefore contribute to the development of cell therapies in future. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Comparison of Chip Inlet Geometry in Microfluidic Devices for Cell Studies

    Directory of Open Access Journals (Sweden)

    Yung-Shin Sun

    2016-06-01

    Full Text Available Micro-fabricated devices integrated with fluidic components provide an in vitro platform for cell studies best mimicking the in vivo micro-environment. These devices are capable of creating precise and controllable surroundings of pH value, temperature, salt concentration, and other physical or chemical stimuli. Various cell studies such as chemotaxis and electrotaxis can be performed by using such devices. Moreover, microfluidic chips are designed and fabricated for applications in cell separations such as circulating tumor cell (CTC chips. Usually, there are two most commonly used inlets in connecting the microfluidic chip to sample/reagent loading tubes: the vertical (top-loading inlet and the parallel (in-line inlet. Designing this macro-to-micro interface is believed to play an important role in device performance. In this study, by using the commercial COMSOL Multiphysics software, we compared the cell capture behavior in microfluidic devices with different inlet types and sample flow velocities. Three different inlets were constructed: the vertical inlet, the parallel inlet, and the vertically parallel inlet. We investigated the velocity field, the flow streamline, the cell capture rate, and the laminar shear stress in these inlets. It was concluded that the inlet should be designed depending on the experimental purpose, i.e., one wants to maximize or minimize cell capture. Also, although increasing the flow velocity could reduce cell sedimentation, too high shear stresses are thought harmful to cells. Our findings indicate that the inlet design and flow velocity are crucial and should be well considered in fabricating microfluidic devices for cell studies.

  1. Device physics underlying silicon heterojunction and passivating-contact solar cells: A topical review

    KAUST Repository

    Chavali, Raghu V. K.

    2018-01-15

    The device physics of commercially dominant diffused-junction silicon solar cells is well understood, allowing sophisticated optimization of this class of devices. Recently, so-called passivating-contact solar cell technologies have become prominent, with Kaneka setting the world\\'s silicon solar cell efficiency record of 26.63% using silicon heterojunction contacts in an interdigitated configuration. Although passivating-contact solar cells are remarkably efficient, their underlying device physics is not yet completely understood, not in the least because they are constructed from diverse materials that may introduce electronic barriers in the current flow. To bridge this gap in understanding, we explore the device physics of passivating contact silicon heterojunction (SHJ) solar cells. Here, we identify the key properties of heterojunctions that affect cell efficiency, analyze the dependence of key heterojunction properties on carrier transport under light and dark conditions, provide a self-consistent multiprobe approach to extract heterojunction parameters using several characterization techniques (including dark J-V, light J-V, C-V, admittance spectroscopy, and Suns-Voc), propose design guidelines to address bottlenecks in energy production in SHJ cells, and develop a process-to-module modeling framework to establish the module\\'s performance limits. We expect that our proposed guidelines resulting from this multiscale and self-consistent framework will improve the performance of future SHJ cells as well as other passivating contact-based solar cells.

  2. A PDMS Device Coupled with Culture Dish for In Vitro Cell Migration Assay.

    Science.gov (United States)

    Lv, Xiaoqing; Geng, Zhaoxin; Fan, Zhiyuan; Wang, Shicai; Pei, WeiHua; Chen, Hongda

    2018-04-30

    Cell migration and invasion are important factors during tumor progression and metastasis. Wound-healing assay and the Boyden chamber assay are efficient tools to investigate tumor development because both of them could be applied to measure cell migration rate. Therefore, a simple and integrated polydimethylsiloxane (PDMS) device was developed for cell migration assay, which could perform quantitative evaluation of cell migration behaviors, especially for the wound-healing assay. The integrated device was composed of three units, which included cell culture dish, PDMS chamber, and wound generation mold. The PDMS chamber was integrated with cell culture chamber and could perform six experiments under different conditions of stimuli simultaneously. To verify the function of this device, it was utilized to explore the tumor cell migration behaviors under different concentrations of fetal bovine serum (FBS) and transforming growth factor (TGF-β) at different time points. This device has the unique capability to create the "wound" area in parallel during cell migration assay and provides a simple and efficient platform for investigating cell migration assay in biomedical application.

  3. Cohesion and device reliability in organic bulk heterojunction photovoltaic cells

    KAUST Repository

    Brand, Vitali

    2012-04-01

    The fracture resistance of P3HT:PC 60BM-based photovoltaic devices are characterized using quantitative adhesion and cohesion metrologies that allow identification of the weakest layer or interface in the device structure. We demonstrate that the phase separated bulk heterojunction layer is the weakest layer and report quantitative cohesion values which ranged from ∼1 to 20 J m -2. The effects of layer thickness, composition, and annealing treatments on layer cohesion are investigated. Using depth profiling and X-ray photoelectron spectroscopy on the resulting fracture surfaces, we examine the gradient of molecular components through the thickness of the bulk heterojunction layer. Finally, using atomic force microscopy we show how the topography of the failure path is related to buckling of the metal electrode and how it develops with annealing. The research provides new insights on how the molecular design, structure and composition affect the cohesive properties of organic photovoltaics. © 2011 Elsevier B.V. All rights reserved.

  4. Paper-based ion concentration polarization device for selective preconcentration of muc1 and lamp-2 genes

    Science.gov (United States)

    Son, Seok Young; Lee, Hyomin; Kim, Sung Jae

    2017-12-01

    Recently, novel biomolecules separation and detection methods based on ion concentration polarization (ICP) phenomena have been extensively researched due to its high amplification ratio and high-speed accumulation. Despite of these bright advances, the fabrication of conventional ICP devices still have complicated and times-consuming tasks. As an alternative platform, a paper have been recently used for the identical ICP operations. In this work, we demonstrated the selective preconcentration of a muc1 gene fragment as human breast cancer marker and a lamp-2 gene fragment as the cause of Danon disease in paper-based ICP devices. As a result, these two DNA fragments were successfully concentrated up to 60 fold at different location in a single paper-channel. The device would be a promising platform for point-of-care device due to an economic fabrication, the easy extraction of concentrated sample and an easy disposability.

  5. Blue light effect on retinal pigment epithelial cells by display devices.

    Science.gov (United States)

    Moon, Jiyoung; Yun, Jieun; Yoon, Yeo Dae; Park, Sang-Il; Seo, Young-Jun; Park, Won-Sang; Chu, Hye Yong; Park, Keun Hong; Lee, Myung Yeol; Lee, Chang Woo; Oh, Soo Jin; Kwak, Young-Shin; Jang, Young Pyo; Kang, Jong Soon

    2017-05-22

    Blue light has high photochemical energy and induces cell apoptosis in retinal pigment epithelial cells. Due to its phototoxicity, retinal hazard by blue light stimulation has been well demonstrated using high intensity light sources. However, it has not been studied whether blue light in the displays, emitting low intensity light, such as those used in today's smartphones, monitors, and TVs, also causes apoptosis in retinal pigment epithelial cells. We attempted to examine the blue light effect on human adult retinal epithelial cells using display devices with different blue light wavelength ranges, the peaks of which specifically appear at 449 nm, 458 nm, and 470 nm. When blue light was illuminated on A2E-loaded ARPE-19 cells using these displays, the display with a blue light peak at a shorter wavelength resulted in an increased production of reactive oxygen species (ROS). Moreover, the reduction of cell viability and induction of caspase-3/7 activity were more evident in A2E-loaded ARPE-19 cells after illumination by the display with a blue light peak at a shorter wavelength, especially at 449 nm. Additionally, white light was tested to examine the effect of blue light in a mixed color illumination with red and green lights. Consistent with the results obtained using only blue light, white light illuminated by display devices with a blue light peak at a shorter wavelength also triggered increased cell death and apoptosis compared to that illuminated by display devices with a blue light peak at longer wavelength. These results show that even at the low intensity utilized in the display devices, blue light can induce ROS production and apoptosis in retinal cells. Our results also suggest that the blue light hazard of display devices might be highly reduced if the display devices contain less short wavelength blue light.

  6. Endothelial and beta cell composite aggregates for improved function of a bioartificial pancreas encapsulation device.

    Science.gov (United States)

    Skrzypek, Katarzyna; Barrera, Yazmin Brito; Groth, Thomas; Stamatialis, Dimitrios

    2018-03-01

    Encapsulation of pancreatic islets or beta cells is a promising strategy for treatment of type 1 diabetes by providing an immune isolated environment and allowing for transplantation in a different location than the liver. However, islets used for encapsulation often show lower functionality due to the damaging of islet endothelial cells during the isolation procedure. Factors produced by endothelial cells have great impact on beta cell insulin secretion. Therefore, mutual signaling between endothelial cells and beta cells should be considered for the development of encapsulation systems to achieve high insulin secretion and maintain beta cell viability. Here, we investigate whether co-culture of beta cells with endothelial cells could improve beta cell function within encapsulation devices. Mouse insulinoma MIN6 cells and human umbilical vein endothelial cells were used for creating composite aggregates on agarose microwell platform. The composite aggregates were encapsulated within flat poly(ether sulfone)/polyvinylpyrrolidone device. Their functionality was assessed by glucose-induced insulin secretion test and compared to non-encapsulated free-floating aggregates. We created composite aggregates of 80-100 µm in diameter, closely mimicking pancreatic islets. Upon glucose stimulation, their insulin secretion is improved in comparison to aggregates consisting of only MIN6 cells. Moreover, the composite aggregates encapsulated within a device secrete more insulin than aggregates consisting of only MIN6 cells. Composite aggregates of MIN6 cells with human umbilical vein endothelial cells have improved insulin secretion in comparison to MIN6 aggregates showing that the interaction of beta cell and endothelial cell is crucial for a functional encapsulation system.

  7. Automatic cell identification and visualization using digital holographic microscopy with head mounted augmented reality devices.

    Science.gov (United States)

    O'Connor, Timothy; Rawat, Siddharth; Markman, Adam; Javidi, Bahram

    2018-03-01

    We propose a compact imaging system that integrates an augmented reality head mounted device with digital holographic microscopy for automated cell identification and visualization. A shearing interferometer is used to produce holograms of biological cells, which are recorded using customized smart glasses containing an external camera. After image acquisition, segmentation is performed to isolate regions of interest containing biological cells in the field-of-view, followed by digital reconstruction of the cells, which is used to generate a three-dimensional (3D) pseudocolor optical path length profile. Morphological features are extracted from the cell's optical path length map, including mean optical path length, coefficient of variation, optical volume, projected area, projected area to optical volume ratio, cell skewness, and cell kurtosis. Classification is performed using the random forest classifier, support vector machines, and K-nearest neighbor, and the results are compared. Finally, the augmented reality device displays the cell's pseudocolor 3D rendering of its optical path length profile, extracted features, and the identified cell's type or class. The proposed system could allow a healthcare worker to quickly visualize cells using augmented reality smart glasses and extract the relevant information for rapid diagnosis. To the best of our knowledge, this is the first report on the integration of digital holographic microscopy with augmented reality devices for automated cell identification and visualization.

  8. All-in-polymer injection molded device for single cell capture using multilevel silicon master fabrication

    DEFF Research Database (Denmark)

    Tanzi, S.; Larsen, S.T.; Matteucci, M.

    2012-01-01

    This work demonstrates a novel all-in-polymer device for single cell capture applicable for biological recordings. The chip is injection molded and comprises a "cornered" (non planar) aperture. It has been demonstrated how cornered apertures are straightforward to mold in PDMS [1,2]. In this stud...... defects during demolding. Capturing of single PC12 cells has been demonstrated.......This work demonstrates a novel all-in-polymer device for single cell capture applicable for biological recordings. The chip is injection molded and comprises a "cornered" (non planar) aperture. It has been demonstrated how cornered apertures are straightforward to mold in PDMS [1,2]. In this study...

  9. Microfluidic device for continuous single cells analysis via Raman spectroscopy enhanced by integrated plasmonic nanodimers

    DEFF Research Database (Denmark)

    Perozziello, Gerardo; Candeloro, Patrizio; De Grazia, Antonio

    2016-01-01

    In this work a Raman flow cytometer is presented. It consists of a microfluidic device that takes advantages of the basic principles of Raman spectroscopy and flow cytometry. The microfluidic device integrates calibrated microfluidic channels-where the cells can flow one-by-one -, allowing single...... cell Raman analysis. The microfluidic channel integrates plasmonic nanodimers in a fluidic trapping region. In this way it is possible to perform Enhanced Raman Spectroscopy on single cell. These allow a label-free analysis, providing information about the biochemical content of membrane and cytoplasm...

  10. Durable left ventricular assist device therapy in advanced heart failure: Patient selection and clinical outcomes

    Science.gov (United States)

    Shah, Sachin P.; Mehra, Mandeep R.

    2016-01-01

    The increasing adoption of left ventricular assist devices (LVADs) into clinical practice is related to a combination of engineering advances in pump technology and improvements in understanding the appropriate clinical use of these devices in the management of patients with advanced heart failure. This review intends to assist the clinician in identifying candidates for LVAD implantation, to examine long-term outcomes and provide an overview of the common complications related to use of these devices. PMID:27056652

  11. Single cell analysis of yeast replicative aging using a new generation of microfluidic device.

    Directory of Open Access Journals (Sweden)

    Yi Zhang

    Full Text Available A major limitation to yeast aging study has been the inability to track mother cells and observe molecular markers during the aging process. The traditional lifespan assay relies on manual micro-manipulation to remove daughter cells from the mother, which is laborious, time consuming, and does not allow long term tracking with high resolution microscopy. Recently, we have developed a microfluidic system capable of retaining mother cells in the microfluidic chambers while removing daughter cells automatically, making it possible to observe fluorescent reporters in single cells throughout their lifespan. Here we report the development of a new generation of microfluidic device that overcomes several limitations of the previous system, making it easier to fabricate and operate, and allowing functions not possible with the previous design. The basic unit of the device consists of microfluidic channels with pensile columns that can physically trap the mother cells while allowing the removal of daughter cells automatically by the flow of the fresh media. The whole microfluidic device contains multiple independent units operating in parallel, allowing simultaneous analysis of multiple strains. Using this system, we have reproduced the lifespan curves for the known long and short-lived mutants, demonstrating the power of the device for automated lifespan measurement. Following fluorescent reporters in single mother cells throughout their lifespan, we discovered a surprising change of expression of the translation elongation factor TEF2 during aging, suggesting altered translational control in aged mother cells. Utilizing the capability of the new device to trap mother-daughter pairs, we analyzed mother-daughter inheritance and found age dependent asymmetric partitioning of a general stress response reporter between mother and daughter cells.

  12. Best practices for media selection for mammalian cells.

    Science.gov (United States)

    Price, Paul J

    2017-09-01

    Cell culture medium is a complex mixture of nutrients and growth factors that, along with the physical environment, can either help or destroy your experiment or production run. Nutritional requirements differ with different cell types and functions, as do optimal pH and osmolality. As cell growth proceeds, different cells will utilize amino acids and other components at different rates. By controlling for ammonia, free radicals, heavy metal toxicity, pH shifts, fluctuations in osmolality, nutrient depletion, and chemical and biological contaminants, you will optimize the chances of success. The contribution of each component of the medium is essential for the maintenance of the cell type of interest. While some cell types, such as established human cancer cell lines, may be quite able to tolerate a range of media and supplements, many normal cells and stems cells are not. Optimization of each component may be required to successfully maintain the latter cell types. The procedures for selecting and optimizing cell culture media and supplements are presented.

  13. An integrated microfluidic device for the sorting of yeast cells using image processing.

    Science.gov (United States)

    Yu, Bo Yang; Elbuken, Caglar; Shen, Chong; Huissoon, Jan Paul; Ren, Carolyn L

    2018-02-23

    The process of detection and separation of yeast cells based on their morphological characteristics is critical to the understanding of cell division cycles, which is of vital importance to the understanding of some diseases such as cancer. The traditional process of manual detection is usually tedious and inconsistent. This paper presents a microfluidic device integrated with microvalves for fluid control for the sorting of yeast cells using image processing algorithms and confirmation based on their fluorescent tag. The proposed device is completely automated, low cost and easy to implement in an academic research setting. Design details of the integrated microfluidic system are highlighted in this paper, along with experimental validation. Real time cell sorting was demonstrated with a cell detection rate of 12 cells per minute.

  14. Microfluidic device for continuous single cells analysis via Raman spectroscopy enhanced by integrated plasmonic nanodimers

    KAUST Repository

    Perozziello, Gerardo

    2015-12-11

    In this work a Raman flow cytometer is presented. It consists of a microfluidic device that takes advantages of the basic principles of Raman spectroscopy and flow cytometry. The microfluidic device integrates calibrated microfluidic channels- where the cells can flow one-by-one -, allowing single cell Raman analysis. The microfluidic channel integrates plasmonic nanodimers in a fluidic trapping region. In this way it is possible to perform Enhanced Raman Spectroscopy on single cell. These allow a label-free analysis, providing information about the biochemical content of membrane and cytoplasm of the each cell. Experiments are performed on red blood cells (RBCs), peripheral blood lymphocytes (PBLs) and myelogenous leukemia tumor cells (K562). © 2015 Optical Society of America.

  15. Insulin-Producing Endocrine Cells Differentiated In Vitro From Human Embryonic Stem Cells Function in Macroencapsulation Devices In Vivo.

    Science.gov (United States)

    Agulnick, Alan D; Ambruzs, Dana M; Moorman, Mark A; Bhoumik, Anindita; Cesario, Rosemary M; Payne, Janice K; Kelly, Jonathan R; Haakmeester, Carl; Srijemac, Robert; Wilson, Alistair Z; Kerr, Justin; Frazier, Mauro A; Kroon, Evert J; D'Amour, Kevin A

    2015-10-01

    The PEC-01 cell population, differentiated from human embryonic stem cells (hESCs), contains pancreatic progenitors (PPs) that, when loaded into macroencapsulation devices (to produce the VC-01 candidate product) and transplanted into mice, can mature into glucose-responsive insulin-secreting cells and other pancreatic endocrine cells involved in glucose metabolism. We modified the protocol for making PEC-01 cells such that 73%-80% of the cell population consisted of PDX1-positive (PDX1+) and NKX6.1+ PPs. The PPs were further differentiated to islet-like cells (ICs) that reproducibly contained 73%-89% endocrine cells, of which approximately 40%-50% expressed insulin. A large fraction of these insulin-positive cells were single hormone-positive and expressed the transcription factors PDX1 and NKX6.1. To preclude a significant contribution of progenitors to the in vivo function of ICs, we used a simple enrichment process to remove remaining PPs, yielding aggregates that contained 93%-98% endocrine cells and 1%-3% progenitors. Enriched ICs, when encapsulated and implanted into mice, functioned similarly to the VC-01 candidate product, demonstrating conclusively that in vitro-produced hESC-derived insulin-producing cells can mature and function in vivo in devices. A scaled version of our suspension culture was used, and the endocrine aggregates could be cryopreserved and retain functionality. Although ICs expressed multiple important β cell genes, the cells contained relatively low levels of several maturity-associated markers. Correlating with this, the time to function of ICs was similar to PEC-01 cells, indicating that ICs required cell-autonomous maturation after delivery in vivo, which would occur concurrently with graft integration into the host. Type 1 diabetes (T1D) affects approximately 1.25 million people in the U.S. alone and is deadly if not managed with insulin injections. This paper describes the production of insulin-producing cells in vitro and a new

  16. Cold atmospheric plasma for selectively ablating metastatic breast cancer cells.

    Science.gov (United States)

    Wang, Mian; Holmes, Benjamin; Cheng, Xiaoqian; Zhu, Wei; Keidar, Michael; Zhang, Lijie Grace

    2013-01-01

    Traditional breast cancer treatments such as surgery and radiotherapy contain many inherent limitations with regards to incomplete and nonselective tumor ablation. Cold atmospheric plasma (CAP) is an ionized gas where the ion temperature is close to room temperature. It contains electrons, charged particles, radicals, various excited molecules, UV photons and transient electric fields. These various compositional elements have the potential to either enhance and promote cellular activity, or disrupt and destroy them. In particular, based on this unique composition, CAP could offer a minimally-invasive surgical approach allowing for specific cancer cell or tumor tissue removal without influencing healthy cells. Thus, the objective of this research is to investigate a novel CAP-based therapy for selectively bone metastatic breast cancer treatment. For this purpose, human metastatic breast cancer (BrCa) cells and bone marrow derived human mesenchymal stem cells (MSCs) were separately treated with CAP, and behavioral changes were evaluated after 1, 3, and 5 days of culture. With different treatment times, different BrCa and MSC cell responses were observed. Our results showed that BrCa cells were more sensitive to these CAP treatments than MSCs under plasma dose conditions tested. It demonstrated that CAP can selectively ablate metastatic BrCa cells in vitro without damaging healthy MSCs at the metastatic bone site. In addition, our study showed that CAP treatment can significantly inhibit the migration and invasion of BrCa cells. The results suggest the great potential of CAP for breast cancer therapy.

  17. Cold atmospheric plasma for selectively ablating metastatic breast cancer cells.

    Directory of Open Access Journals (Sweden)

    Mian Wang

    Full Text Available Traditional breast cancer treatments such as surgery and radiotherapy contain many inherent limitations with regards to incomplete and nonselective tumor ablation. Cold atmospheric plasma (CAP is an ionized gas where the ion temperature is close to room temperature. It contains electrons, charged particles, radicals, various excited molecules, UV photons and transient electric fields. These various compositional elements have the potential to either enhance and promote cellular activity, or disrupt and destroy them. In particular, based on this unique composition, CAP could offer a minimally-invasive surgical approach allowing for specific cancer cell or tumor tissue removal without influencing healthy cells. Thus, the objective of this research is to investigate a novel CAP-based therapy for selectively bone metastatic breast cancer treatment. For this purpose, human metastatic breast cancer (BrCa cells and bone marrow derived human mesenchymal stem cells (MSCs were separately treated with CAP, and behavioral changes were evaluated after 1, 3, and 5 days of culture. With different treatment times, different BrCa and MSC cell responses were observed. Our results showed that BrCa cells were more sensitive to these CAP treatments than MSCs under plasma dose conditions tested. It demonstrated that CAP can selectively ablate metastatic BrCa cells in vitro without damaging healthy MSCs at the metastatic bone site. In addition, our study showed that CAP treatment can significantly inhibit the migration and invasion of BrCa cells. The results suggest the great potential of CAP for breast cancer therapy.

  18. A cell sorting and trapping microfluidic device with an interdigital channel

    Directory of Open Access Journals (Sweden)

    Jing Tu

    2016-12-01

    Full Text Available The growing interest in cell sorting and trapping is driving the demand for high performance technologies. Using labeling techniques or external forces, cells can be identified by a series of methods. However, all of these methods require complicated systems with expensive devices. Based on inherent differences in cellular morphology, cells can be sorted by specific structures in microfluidic devices. The weir filter is a basic and efficient cell sorting and trapping structure. However, in some existing weir devices, because of cell deformability and high flow velocity in gaps, trapped cells may become stuck or even pass through the gaps. Here, we designed and fabricated a microfluidic device with interdigital channels for cell sorting and trapping. The chip consisted of a sheet of silicone elastomer polydimethylsiloxane and a sheet of glass. A square-wave-like weir was designed in the middle of the channel, comprising the interdigital channels. The square-wave pattern extended the weir length by three times with the channel width remaining constant. Compared with a straight weir, this structure exhibited a notably higher trapping capacity. Interdigital channels provided more space to slow down the rate of the pressure decrease, which prevented the cells from becoming stuck in the gaps. Sorting a mixture K562 and blood cells to trap cells demonstrated the efficiency of the chip with the interdigital channel to sort and trap large and less deformable cells. With stable and efficient cell sorting and trapping abilities, the chip with an interdigital channel may be widely applied in scientific research fields.

  19. Device for welding a connection line to an electrode of a solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Lorans, D.Y.

    1976-08-05

    A method with associated device for welding connection lines to the electrodes of solar cells is described. To improve the weldability of the contacts usually consisting of silver, a weld-receiving device is vibrated with respect to the welding electrode, whereby disturbing surface layers are destroyed with a certain application pressure of the welding electrode. The method shows better results than, for example, a previous chemical cleaning of the contacts and is also more easy to handle.

  20. A new portable device for automatic controlled-gradient cryopreservation of blood mononuclear cells

    DEFF Research Database (Denmark)

    Hviid, L; Albeck, G; Hansen, B

    1993-01-01

    -controlled freezing devices. While such equipment offers large capacity and secures maximum survival and functional integrity of the lymphocytes upon thawing, it is quite costly and strictly stationary. We have previously developed and tested an alternative, manual device for controlled-gradient lymphocyte freezing......, which has proved suitable for field conditions. We report here the development and testing of a similar micro-controller regulated device, allowing unattended and automatic controlled-gradient cell freezing. The equipment exploits the temperature gradient present between the liquid N2 surface...

  1. A replication-casting device for manufacturing open-cell Mg foams

    OpenAIRE

    Lara-Rodriguez, G.A.; Figueroa, I.A.; Suarez, M.A.; Novelo-Peralta, O.; Alfonso, I.; Goodall, R.

    2016-01-01

    The development of a replication casting device with the capability of manufacturing open-cell pure Mg and Mg alloys foams, with melting points lower than 950 °C is described. The device consists of three basic parts: a cylindrical reaction chamber, a valve system for controlling the vacuum and the gas injection, and a heating system. The purpose of the present design was to improve the existing laboratory-scale devices, making them simpler than those reported in the literature, as well as to...

  2. [The cell phones as devices for the ocular fundus documentation].

    Science.gov (United States)

    Němčanský, J; Kopecký, A; Timkovič, J; Mašek, P

    2014-12-01

    To present our experience with "smart phones" when examining and documenting human eyes. From September to October 2013 fifteen patients (8 men, 7 women) eye fundus was examined, an average age during the examination was 58 year (ranging from 20-65 years). The photo-documentation was performed with dilated pupils (tropicamid hydrochloridum 1% eye drops) with mobile phone Samsung Galaxy Nexus with the operating system Android 4.3 (Google Inc., Mountain View, CA, USA) and iPhone 4 with the operating system 7.0.4 (Apple Inc., Loop Cupertino, CA, USA), and with 20D lens (Volk Optical Inc., Mentor, OH, USA). The images of the retina taken with a mobile phone and the spherical lens are of a very good quality, precise and reproducible. Learning this technique is easy and fast, the learning curve is steep. Photo-documentation of retina with a mobile phone is a safe, time-saving, easy-to-learn technique, which may be used in a routine ophthalmologic practice. The main advantage of this technique is availability, small size and easy portability of the devices.

  3. A new portable device for automatic controlled-gradient cryopreservation of blood mononuclear cells

    DEFF Research Database (Denmark)

    Hviid, L; Albeck, G; Hansen, B

    1993-01-01

    , which has proved suitable for field conditions. We report here the development and testing of a similar micro-controller regulated device, allowing unattended and automatic controlled-gradient cell freezing. The equipment exploits the temperature gradient present between the liquid N2 surface......Protection of the functional integrity of mononuclear cells stored in liquid N2 requires careful control of the freezing procedure. Consequently, optimal quality of cryopreserved cells is usually assured by freezing according to a specified time-temperature gradient generated by computer-controlled...... freezing devices. While such equipment offers large capacity and secures maximum survival and functional integrity of the lymphocytes upon thawing, it is quite costly and strictly stationary. We have previously developed and tested an alternative, manual device for controlled-gradient lymphocyte freezing...

  4. Investigating the feasibility of symmetric guanidinium based plumbate perovskites in prototype solar cell devices

    Science.gov (United States)

    Kulkarni, Sneha A.; Baikie, Tom; Muduli, Subas; Potter, Rob; Chen, Shi; Yanan, Fanan; Bishop, Peter; Sien Lim, Swee; Chien Sum, Tze; Mathews, Nripan; White, Tim J.

    2017-08-01

    In this work we have studied the feasibility of highly symmetric guanidinium (GA; CH6N3 +) cation in perovskite based solar cells. It is an alternative to the methyl ammonium (MA; CH3NH3 +) or formamidinium (FA; CH(NH2)2+) ions commonly utilized in the perovskite solar cells, may bring additional advantages due to its triad rotational symmetry and zero dipole moment (μ). We noticed that due to steric factors, GA preferably forms two-dimensional (2D) layer, where GA2PbI4 is favored monoclinic structure (E g = 2.5 eV) and the obtained device efficiency is η = 0.45%. This study provides a guideline for designing guanidinium based perovskite absorbers for solar cell devices. In addition, through further compositional engineering with mixed organic cations using GA may enhance the device performance.

  5. Rhodacyanine derivative selectively targets cancer cells and overcomes tamoxifen resistance.

    Directory of Open Access Journals (Sweden)

    John Koren

    Full Text Available MKT-077, a rhodacyanine dye, was shown to produce cancer specific cell death. However, complications prevented the use of this compound beyond clinical trials. Here we describe YM-1, a derivative of MKT-077. We found that YM-1 was more cytotoxic and localized differently than MKT-077. YM-1 demonstrated this cytotoxicity across multiple cancer cell lines. This toxicity was limited to cancer cell lines; immortalized cell models were unaffected. Brief applications of YM-1 were found to be non-toxic. Brief treatment with YM-1 restored tamoxifen sensitivity to a refractory tamoxifen-resistant MCF7 cell model. This effect is potentially due to altered estrogen receptor alpha phosphorylation, an outcome precipitated by selective reductions in Akt levels (Akt/PKB. Thus, modifications to the rhodocyanine scaffold could potentially be made to improve efficacy and pharmacokinetic properties. Moreover, the impact on tamoxifen sensitivity could be a new utility for this compound family.

  6. Development of standard technical report on using and selecting wireless device in nuclear power plants

    International Nuclear Information System (INIS)

    Koo, I. S.; Hong, S. B.; Cho, J. W.

    2011-11-01

    1. Purpose · Development of IEC technical report on wireless device using in nuclear power plants 2. Contents · IEC technical reports of draft for circulation and final draft for next planary meeting · Case study on experiment of wireless devices 3. Implementation methods · Preparation of first draft with experts group, its circulation, discussions on the results of the circulation · Organizing three teams such as preparation, reviews and experiment 4. Results · Maintenance cost will be reduced with application of the wireless technologies in nuclear power plants · Commercial wireless devices will be developed before standard is issued

  7. Stretchable living materials and devices with hydrogel-elastomer hybrids hosting programmed cells.

    Science.gov (United States)

    Liu, Xinyue; Tang, Tzu-Chieh; Tham, Eléonore; Yuk, Hyunwoo; Lin, Shaoting; Lu, Timothy K; Zhao, Xuanhe

    2017-02-28

    Living systems, such as bacteria, yeasts, and mammalian cells, can be genetically programmed with synthetic circuits that execute sensing, computing, memory, and response functions. Integrating these functional living components into materials and devices will provide powerful tools for scientific research and enable new technological applications. However, it has been a grand challenge to maintain the viability, functionality, and safety of living components in freestanding materials and devices, which frequently undergo deformations during applications. Here, we report the design of a set of living materials and devices based on stretchable, robust, and biocompatible hydrogel-elastomer hybrids that host various types of genetically engineered bacterial cells. The hydrogel provides sustainable supplies of water and nutrients, and the elastomer is air-permeable, maintaining long-term viability and functionality of the encapsulated cells. Communication between different bacterial strains and with the environment is achieved via diffusion of molecules in the hydrogel. The high stretchability and robustness of the hydrogel-elastomer hybrids prevent leakage of cells from the living materials and devices, even under large deformations. We show functions and applications of stretchable living sensors that are responsive to multiple chemicals in a variety of form factors, including skin patches and gloves-based sensors. We further develop a quantitative model that couples transportation of signaling molecules and cellular response to aid the design of future living materials and devices.

  8. Laser Process for Selective Emitter Silicon Solar Cells

    Directory of Open Access Journals (Sweden)

    G. Poulain

    2012-01-01

    Full Text Available Selective emitter solar cells can provide a significant increase in conversion efficiency. However current approaches need many technological steps and alignment procedures. This paper reports on a preliminary attempt to reduce the number of processing steps and therefore the cost of selective emitter cells. In the developed procedure, a phosphorous glass covered with silicon nitride acts as the doping source. A laser is used to open locally the antireflection coating and at the same time achieve local phosphorus diffusion. In this process the standard chemical etching of the phosphorous glass is avoided. Sheet resistance variation from 100 Ω/sq to 40 Ω/sq is demonstrated with a nanosecond UV laser. Numerical simulation of the laser-matter interaction is discussed to understand the dopant diffusion efficiency. Preliminary solar cells results show a 0.5% improvement compared with a homogeneous emitter structure.

  9. Tantalum Nitride Electron-Selective Contact for Crystalline Silicon Solar Cells

    KAUST Repository

    Yang, Xinbo

    2018-04-19

    Minimizing carrier recombination at contact regions by using carrier‐selective contact materials, instead of heavily doping the silicon, has attracted considerable attention for high‐efficiency, low‐cost crystalline silicon (c‐Si) solar cells. A novel electron‐selective, passivating contact for c‐Si solar cells is presented. Tantalum nitride (TaN x ) thin films deposited by atomic layer deposition are demonstrated to provide excellent electron‐transporting and hole‐blocking properties to the silicon surface, due to their small conduction band offset and large valence band offset. Thin TaNx interlayers provide moderate passivation of the silicon surfaces while simultaneously allowing a low contact resistivity to n‐type silicon. A power conversion efficiency (PCE) of over 20% is demonstrated with c‐Si solar cells featuring a simple full‐area electron‐selective TaNx contact, which significantly improves the fill factor and the open circuit voltage (Voc) and hence provides the higher PCE. The work opens up the possibility of using metal nitrides, instead of metal oxides, as carrier‐selective contacts or electron transport layers for photovoltaic devices.

  10. Sodium selectivity of semicircular canal duct epithelial cells

    Directory of Open Access Journals (Sweden)

    Harbidge Donald G

    2011-09-01

    Full Text Available Abstract Background Sodium absorption by semicircular canal duct (SCCD epithelial cells is thought to contribute to the homeostasis of the volume of vestibular endolymph. It was previously shown that the epithelial cells could absorb Na+ under control of a glucocorticoid hormone (dexamethasone and the absorptive transepithelial current was blocked by amiloride. The most commonly-observed target of amiloride is the epithelial sodium channel (ENaC, comprised of the three subunits α-, β- and γ-ENaC. However, other cation channels have also been observed to be sensitive in a similar concentration range. The aim of this study was to determine whether SCCD epithelial cells absorb only Na+ or also K+ through an amiloride-sensitive pathway. Parasensory K+ absorption could contribute to regulation of the transduction current through hair cells, as found to occur via vestibular transitional cells [S. H. Kim and D. C. Marcus. Regulation of sodium transport in the inner ear. Hear.Res. doi:10.1016/j.heares.2011.05.003, 2011]. Results We determined the molecular and functional expression of candidate cation channels with gene array (GEO GSE6197, whole-cell patch clamp and transepithelial recordings in primary cultures of rat SCCD. α-, β- and γ-ENaC were all previously reported as present. The selectivity of the amiloride-sensitive transepithelial and cell membrane currents was observed in Ussing chamber and whole-cell patch clamp recordings. The cell membrane currents were carried by Na+ but not K+, but the Na+ selectivity disappeared when the cells were cultured on impermeable supports. Transepithelial currents across SCCD were also carried exclusively by Na+. Conclusions These results are consistent with the amiloride-sensitive absorptive flux of SCCD mediated by a highly Na+-selective channel, likely αβγ-ENaC. These epithelial cells therefore absorb only Na+ via the amiloride-sensitive pathway and do not provide a parasensory K+ efflux from the

  11. Building-Integrated Solar Energy Devices based on Wavelength Selective Films

    Science.gov (United States)

    Ulavi, Tejas

    A potentially attractive option for building integrated solar is to employ hybrid solar collectors which serve dual purposes, combining solar thermal technology with either thin film photovoltaics or daylighting. In this study, two hybrid concepts, a hybrid photovoltaic/thermal (PV/T) collector and a hybrid 'solar window', are presented and analyzed to evaluate technical performance. In both concepts, a wavelength selective film is coupled with a compound parabolic concentrator (CPC) to reflect and concentrate the infrared portion of the solar spectrum onto a tubular absorber. The visible portion of the spectrum is transmitted through the concentrator to either a thin film Cadmium Telluride (CdTe) solar panel for electricity generation or into the interior space for daylighting. Special attention is given to the design of the hybrid devices for aesthetic building integration. An adaptive concentrator design based on asymmetrical truncation of CPCs is presented for the hybrid solar window concept. The energetic and spectral split between the solar thermal module and the PV or daylighting module are functions of the optical properties of the wavelength selective film and the concentrator geometry, and are determined using a Monte Carlo Ray-Tracing (MCRT) model. Results obtained from the MCRT can be used in conjugation with meteorological data for specific applications to study the impact of CPC design parameters including the half-acceptance angle thetac, absorber diameter D and truncation on the annual thermal and PV/daylighting efficiencies. The hybrid PV/T system is analyzed for a rooftop application in Phoenix, AZ. Compared to a system of the same area with independent solar thermal and PV modules, the hybrid PV/T provides 20% more energy, annually. However, the increase in total delivered energy is due solely to the addition of the thermal module and is achieved at an expense of a decrease in the annual electrical efficiency from 8.8% to 5.8% due to shading by

  12. Subtractive Cell-SELEX Selection of DNA Aptamers Binding Specifically and Selectively to Hepatocellular Carcinoma Cells with High Metastatic Potential

    Directory of Open Access Journals (Sweden)

    Hao Chen

    2016-01-01

    Full Text Available Relapse and metastasis are two key risk factors of hepatocellular carcinoma (HCC prognosis; thus, it is emergent to develop an early and accurate detection method for prognostic evaluation of HCC after surgery. In this study, we sought to acquire oligonucleotide DNA aptamers that specifically bind to HCC cells with high metastatic potential. Two HCC cell lines derived from the same genetic background but with different metastatic potential were employed: MHCC97L (low metastatic properties as subtractive targets and HCCLM9 (high metastatic properties as screening targets. To mimic a fluid combining environment, initial DNA aptamers library was firstly labelled with magnetic nanoparticles using biotin-streptavidin system and then applied for aptamers selection. Through 10-round selection with subtractive Cell-SELEX, six aptamers, LY-1, LY-13, LY-46, LY-32, LY-27/45, and LY-7/43, display high affinity to HCCLM9 cells and do not bind to MHCC97L cells, as well as other tumor cell lines, including breast cancer, lung cancer, colon adenocarcinoma, gastric cancer, and cervical cancer, suggesting high specificity for HCCLM9 cells. Thus, the aptamers generated here will provide solid basis for identifying new diagnostic targets to detect HCC metastasis and also may provide valuable clues for developing new targeted therapeutics.

  13. Starburst cells nondirectionally facilitate the responses of direction-selective retinal ganglion cells.

    Science.gov (United States)

    Chiao, Chuan-Chin; Masland, Richard H

    2002-12-15

    The mechanism of direction selectivity in retinal ganglion cells remains controversial. An important issue is how the starburst amacrine cells, which are known to provide a major synaptic input to the direction-selective ganglion cells, participate in the directional discrimination. Here, we present evidence that the cholinergic outputs of the starburst cells affect the responses of the ganglion cells symmetrically; they provide a feedforward excitation that facilitates the response of the ganglion cells to movement in both the preferred and null directions. This seems to place a constraint on models of the directional discrimination in which the starburst cells participate, namely, that their cholinergic synapses be nondirectional in their effects on the ganglion cells.

  14. Study of surface modifications for improved selected metal (II-VI) semiconductor based devices

    Science.gov (United States)

    Blomfield, Christopher James

    Metal-semiconductor contacts are of fundamental importance to the operation of all semiconductor devices. There are many competing theories of Schottky barrier formation but as yet no quantitative predictive model exists to adequately explain metal-semiconductor interfaces. The II-VI compound semiconductors CdTe, CdS and ZnSe have recently come to the fore with the advent of high efficiency photovoltaic cells and short wavelength light emitters. Major problems still exist however in forming metal contacts to these materials with the desired properties. This work presents results which make a significant contribution to the theory of metal/II-VI interface behaviour in terms of Schottky barriers to n-type CdTe, CdS and ZnSe.Predominantly aqueous based wet chemical etchants were applied to the surfaces of CdTe, CdS and ZnSe which were subsequently characterised by X-ray photoelectron spectroscopy. The ionic nature of these II-VI compounds meant that they behaved as insoluble salts of strong bases and weak acids. Acid etchants induced a stoichiometric excess of semiconductor anion at the surface which appeared to be predominantly in the elemental or hydrogenated state. Alkaline etchants conversely induced a stoichiometric excess of semiconductor cation at the surface which appeared to be in an oxidised state.Metal contacts were vacuum-evaporated onto these etched surfaces and characterised by current-voltage and capacitance-voltage techniques. The surface preparation was found to have a clear influence upon the electrical properties of Schottky barriers formed to etched surfaces. Reducing the native surface oxide produced near ideal Schottky diodes. An extended study of Au, Ag and Sb contacts to [mathematical formula] substrates again revealed the formation of several discrete Schottky barriers largely independent of the metal used; for [mathematical formula]. Deep levels measured within this study and those reported in the literature led to the conclusion that Fermi

  15. Room-temperature treatments for all-inorganic nanocrystal solar cell devices

    Energy Technology Data Exchange (ETDEWEB)

    Loiudice, Anna, E-mail: anna.loiudice@iit.it [Dipartimento di Matematica e Fisica " E. De Giorgi" , Università del Salento, via Arnesano, 73100 Lecce (Italy); CBN — Center for Biomolecular Nanotechnologies, Italian Institute of Technology, Energy Platform, Via Barsanti sn, 73010 Arnesano (Lecce) (Italy); Rizzo, Aurora [CBN — Center for Biomolecular Nanotechnologies, Italian Institute of Technology, Energy Platform, Via Barsanti sn, 73010 Arnesano (Lecce) (Italy); NNL CNR-Istituto Nanoscienze, c/o Distretto Tecnologico, via per Arnesano km. 5, 73100 Lecce (Italy); Corricelli, Michela [Istituto per i Processi Chimico Fisici (IPCF-CNR) Bari, c/o Department of Chemistry, University of Bari, Via Orabona 4, I-70126 Bari (Italy); Department of Chemistry, University of Bari, Via Orabona 4, I-70126 Bari (Italy); Curri, M. Lucia [Istituto per i Processi Chimico Fisici (IPCF-CNR) Bari, c/o Department of Chemistry, University of Bari, Via Orabona 4, I-70126 Bari (Italy); Belviso, Maria R. [NNL CNR-Istituto Nanoscienze, c/o Distretto Tecnologico, via per Arnesano km. 5, 73100 Lecce (Italy); Cozzoli, P. Davide [Dipartimento di Matematica e Fisica " E. De Giorgi" , Università del Salento, via Arnesano, 73100 Lecce (Italy); NNL CNR-Istituto Nanoscienze, c/o Distretto Tecnologico, via per Arnesano km. 5, 73100 Lecce (Italy); Grancini, Giulia; Petrozza, Annamaria [Center for Nano Science and Technology at PoliMi, Istituto Italiano di Tecnologia, Via Pascoli 70/3, 20133 Milano (Italy); Gigli, Giuseppe [Dipartimento di Matematica e Fisica " E. De Giorgi" , Università del Salento, via Arnesano, 73100 Lecce (Italy); CBN — Center for Biomolecular Nanotechnologies, Italian Institute of Technology, Energy Platform, Via Barsanti sn, 73010 Arnesano (Lecce) (Italy); NNL CNR-Istituto Nanoscienze, c/o Distretto Tecnologico, via per Arnesano km. 5, 73100 Lecce (Italy)

    2014-06-02

    We have developed a room-temperature solution processing approach to integrate colloidal anatase titanium dioxide nanorods (TiO{sub 2} NRs) and lead sulfide quantum dots (PbS QDs) into a heterostructured p-n junction device. To this aim we have exploited a post-deposition treatment to remove surface-adsorbed ligands by means of UV-light-irradiation of TiO{sub 2} NRs and a dilute acid treatment of PbS QDs. Here we report a systematic study on the optimization of the post-deposition treatments and device fabrication. Our approach is fully compatible with plastic device technology and is potentially useful for the integration of crystalline TiO{sub 2} as active component into disparate solar cell architectures and organic optoelectronic devices. - Highlights: • Colloidal nanocrystals offer path to low-cost manufacturing atop flexible substrates. • We fabricate an all-inorganic solar cell under room temperature treatments. • Our approach is fully compatible with plastic device technology. • It is useful for the integration of nanocrystals into disparate device architectures.

  16. Microfluidic device for rapid solution exchange to study kinetics of cell physiology

    Science.gov (United States)

    Hu, Howard; Honnatti, Meghana; Gillis, Kevin

    2006-11-01

    Exchanging the extracellular solution of the cell rapidly (less than 10ms) is an important requirement in study the kinetics of cell physiology. A microfluidic device is developed to exchange the solution around the cells as they flow through a junction at the intersection of two microfluidic channels. The solution exchange time is measured experimentally by fluorescently labeling the cell surface membranes with a styryl dye, FM1-43 or FM 2-10, and then observing the time course of cell fluorescence decay following the rapid drop in the extracellular concentration of the FM dye that occurs as the cell flows past the fluidic junction. A numerical model is developed to guide the experimental design of microfluidic device. In the model, the motion of a single cell through a fluid junction is simulated and the mixing process of the solutions is solved. The model also includes the kinetics of departitioning of FM dyes from the cell membrane. The departitioning time constants for the FM dyes are determined from fitting the measured data of the cell fluorescence decay. This departitioning kinetics is important as FM dyes are commonly used to label cell membranes for the purpose of measuring the release of neurotransmitter from synaptic vesicles via exocytosis and the subsequent reuptake of vesicular membrane by endocytosis.

  17. Nanocrystalline Silicon Carrier Collectors for Silicon Heterojunction Solar Cells and Impact on Low-Temperature Device Characteristics

    KAUST Repository

    Nogay, Gizem

    2016-09-26

    Silicon heterojunction solar cells typically use stacks of hydrogenated intrinsic/doped amorphous silicon layers as carrier selective contacts. However, the use of these layers may cause parasitic optical absorption losses and moderate fill factor (FF) values due to a high contact resistivity. In this study, we show that the replacement of doped amorphous silicon with nanocrystalline silicon is beneficial for device performance. Optically, we observe an improved short-circuit current density when these layers are applied to the front side of the device. Electrically, we observe a lower contact resistivity, as well as higher FF. Importantly, our cell parameter analysis, performed in a temperature range from -100 to +80 °C, reveals that the use of hole-collecting p-type nanocrystalline layer suppresses the carrier transport barrier, maintaining FF s in the range of 70% at -100 °C, whereas it drops to 40% for standard amorphous doped layers. The same analysis also reveals a saturation onset of the open-circuit voltage at -100 °C using doped nanocrystalline layers, compared with saturation onset at -60 °C for doped amorphous layers. These findings hint at a reduced importance of the parasitic Schottky barrier at the interface between the transparent electrodes and the selective contact in the case of nanocrystalline layer implementation. © 2011-2012 IEEE.

  18. Enhancement of device performance of organic solar cells by an interfacial perylene derivative layer

    KAUST Repository

    Kim, Inho

    2010-05-26

    We report that device performance of organic solar cells consisting of zinc phthalocyanine and fullerene (C60) can be enhanced by insertion of a perylene derivative interfacial layer between fullerene and bathocuproine (BCP) exciton blocking layer (EBL). The morphology of the BCP is influenced by the underlying N,N′-dihexyl-perylene-3,4,9,10-bis(dicarboximide) (PTCDI-C6), which promotes migration of the cathode metal into the BCP layer. Insertion of a PTCDI-C6 layer between fullerene and BCP layers enhances the power conversion efficiency to 2.5%, an improvement of 32% over devices without PTCDI-C6 layer. The enhancement in device performance by insertion of PTCDI-C6 is attributed to a reduction in series resistance due to promoted metal migration into BCP and optimized optical interference effects in multilayered devices. © 2010 American Chemical Society.

  19. Cell membrane-inspired phospholipid polymers for developing medical devices with excellent biointerfaces

    Directory of Open Access Journals (Sweden)

    Yasuhiko Iwasaki

    2012-01-01

    Full Text Available This review article describes fundamental aspects of cell membrane-inspired phospholipid polymers and their usefulness in the development of medical devices. Since the early 1990s, polymers composed of 2-methacryloyloxyethyl phosphorylcholine (MPC units have been considered in the preparation of biomaterials. MPC polymers can provide an artificial cell membrane structure at the surface and serve as excellent biointerfaces between artificial and biological systems. They have also been applied in the surface modification of some medical devices including long-term implantable artificial organs. An MPC polymer biointerface can suppress unfavorable biological reactions such as protein adsorption and cell adhesion – in other words, specific biomolecules immobilized on an MPC polymer surface retain their original functions. MPC polymers are also being increasingly used for creating biointerfaces with artificial cell membrane structures.

  20. Deformability-based red blood cell separation in deterministic lateral displacement devices-A simulation study.

    Science.gov (United States)

    Krüger, Timm; Holmes, David; Coveney, Peter V

    2014-09-01

    We show, via three-dimensional immersed-boundary-finite-element-lattice-Boltzmann simulations, that deformability-based red blood cell (RBC) separation in deterministic lateral displacement (DLD) devices is possible. This is due to the deformability-dependent lateral extension of RBCs and enables us to predict a priori which RBCs will be displaced in a given DLD geometry. Several diseases affect the deformability of human cells. Malaria-infected RBCs, for example, tend to become stiffer than their healthy counterparts. It is therefore desirable to design microfluidic devices which can detect diseases based on the cells' deformability fingerprint, rather than preparing samples using expensive and time-consuming biochemical preparation steps. Our findings should be helpful in the development of new methods for sorting cells and particles by deformability.

  1. Chromium Trioxide Hole-Selective Heterocontacts for Silicon Solar Cells.

    Science.gov (United States)

    Lin, Wenjie; Wu, Weiliang; Liu, Zongtao; Qiu, Kaifu; Cai, Lun; Yao, Zhirong; Ai, Bin; Liang, Zongcun; Shen, Hui

    2018-04-25

    A high recombination rate and high thermal budget for aluminum (Al) back surface field are found in the industrial p-type silicon solar cells. Direct metallization on lightly doped p-type silicon, however, exhibits a large Schottky barrier for the holes on the silicon surface because of Fermi-level pinning effect. As a result, low-temperature-deposited, dopant-free chromium trioxide (CrO x , x solar cell as a hole-selective contact at the rear surface. By using 4 nm CrO x between the p-type silicon and Ag, we achieve a reduction of the contact resistivity for the contact of Ag directly on p-type silicon. For further improvement, we utilize a CrO x (2 nm)/Ag (30 nm)/CrO x (2 nm) multilayer film on the contact between Ag and p-type crystalline silicon (c-Si) to achieve a lower contact resistance (40 mΩ·cm 2 ). The low-resistivity Ohmic contact is attributed to the high work function of the uniform CrO x film and the depinning of the Fermi level of the SiO x layer at the silicon interface. Implementing the advanced hole-selective contacts with CrO x /Ag/CrO x on the p-type silicon solar cell results in a power conversion efficiency of 20.3%, which is 0.1% higher than that of the cell utilizing 4 nm CrO x . Compared with the commercialized p-type solar cell, the novel CrO x -based hole-selective transport material opens up a new possibility for c-Si solar cells using high-efficiency, low-temperature, and dopant-free deposition techniques.

  2. Building Cell Selectivity into CPP-Mediated Strategies

    Directory of Open Access Journals (Sweden)

    Irene Martín

    2010-05-01

    Full Text Available There is a pressing need for more effective and selective therapies for cancer and other diseases. Consequently, much effort is being devoted to the development of alternative experimental approaches based on selective systems, which are designed to be specifically directed against target cells. In addition, a large number of highly potent therapeutic molecules are being discovered. However, they do not reach clinical trials because of their low delivery, poor specificity or their incapacity to bypass the plasma membrane. Cell-penetrating peptides (CPPs are an open door for cell-impermeable compounds to reach intracellular targets. Putting all these together, research is sailing in the direction of the design of systems with the capacity to transport new drugs into a target cell. Some CPPs show cell type specificity while others require modifications or form part of more sophisticated drug delivery systems. In this review article we summarize several strategies for directed drug delivery involving CPPs that have been reported in the literature.

  3. A design handbook for phase change thermal control and energy storage devices. [selected paraffins

    Science.gov (United States)

    Humphries, W. R.; Griggs, E. I.

    1977-01-01

    Comprehensive survey is given of the thermal aspects of phase change material devices. Fundamental mechanisms of heat transfer within the phase change device are discussed. Performance in zero-g and one-g fields are examined as it relates to such a device. Computer models for phase change materials, with metal fillers, undergoing conductive and convective processes are detailed. Using these models, extensive parametric data are presented for a hypothetical configuration with a rectangular phase change housing, using straight fins as the filler, and paraffin as the phase change material. These data are generated over a range of realistic sizes, material properties, and thermal boundary conditions. A number of illustrative examples are given to demonstrate use of the parametric data. Also, a complete listing of phase change material property data are reproduced herein as an aid to the reader.

  4. Selected fault testing of electronic isolation devices used in nuclear power plant operation

    International Nuclear Information System (INIS)

    Villaran, M.; Hillman, K.; Taylor, J.; Lara, J.; Wilhelm, W.

    1994-05-01

    Electronic isolation devices are used in nuclear power plants to provide electrical separation between safety and non-safety circuits and systems. Major fault testing in an earlier program indicated that some energy may pass through an isolation device when a fault at the maximum credible potential is applied in the transverse mode to its output terminals. During subsequent field qualification testing of isolators, concerns were raised that the worst case fault, that is, the maximum credible fault (MCF), may not occur with a fault at the maximum credible potential, but rather at some lower potential. The present test program investigates whether problems can arise when fault levels up to the MCF potential are applied to the output terminals of an isolator. The fault energy passed through an isolated device during a fault was measured to determine whether the levels are great enough to potentially damage or degrade performance of equipment on the input (Class 1E) side of the isolator

  5. Selected fault testing of electronic isolation devices used in nuclear power plant operation

    Energy Technology Data Exchange (ETDEWEB)

    Villaran, M.; Hillman, K.; Taylor, J.; Lara, J.; Wilhelm, W. [Brookhaven National Lab., Upton, NY (United States)

    1994-05-01

    Electronic isolation devices are used in nuclear power plants to provide electrical separation between safety and non-safety circuits and systems. Major fault testing in an earlier program indicated that some energy may pass through an isolation device when a fault at the maximum credible potential is applied in the transverse mode to its output terminals. During subsequent field qualification testing of isolators, concerns were raised that the worst case fault, that is, the maximum credible fault (MCF), may not occur with a fault at the maximum credible potential, but rather at some lower potential. The present test program investigates whether problems can arise when fault levels up to the MCF potential are applied to the output terminals of an isolator. The fault energy passed through an isolated device during a fault was measured to determine whether the levels are great enough to potentially damage or degrade performance of equipment on the input (Class 1E) side of the isolator.

  6. Mkit: A Cell Migration Assay Based on Microfluidic Device and Smartphone

    OpenAIRE

    Yang, Ke; Wu, Jiandong; Peretz-Soroka, Hagit; Zhu, Ling; Li, Zhigang; Sang, Yaoshuo; Hipolito, Jolly; Zhang, Michael; Santos, Susy; Hillier, Craig; de Faria, Ricardo Lobato; Liu, Yong; Lin, Francis

    2017-01-01

    Mobile sensing based on the integration of microfluidic device and smartphone, so-called MS2 technology, has enabled many applications over recent years, and continues to stimulate growing interest in both research communities and industries. In particular, it has been envisioned that MS2 technology can be developed for various cell functional assays to enable basic research and clinical applications. Toward this direction, in this paper, we describe the development of a MS2-based cell functi...

  7. Asymmetric director structures and flexoelectricity in nematic pi-cell devices

    Science.gov (United States)

    Tartan, Chloe C.; Elston, Steve J.

    2015-08-01

    The sum of the flexoelectric coefficients in a liquid crystal material has been measured in nematic pi-cell devices, based on a method that exploits the asymmetry in the director configurations of the different states in a pi-cell, the uniform surface alignment polarities, and the influence of ions. A value of |e1 + e3| = 10 pC m-1 was measured from data-theory comparisons in the standard commercial eutectic E7 nematic liquid crystal mixture.

  8. Conductivity based on selective etch for GaN devices and applications thereof

    Science.gov (United States)

    Zhang, Yu; Sun, Qian; Han, Jung

    2015-12-08

    This invention relates to methods of generating NP gallium nitride (GaN) across large areas (>1 cm.sup.2) with controlled pore diameters, pore density, and porosity. Also disclosed are methods of generating novel optoelectronic devices based on porous GaN. Additionally a layer transfer scheme to separate and create free-standing crystalline GaN thin layers is disclosed that enables a new device manufacturing paradigm involving substrate recycling. Other disclosed embodiments of this invention relate to fabrication of GaN based nanocrystals and the use of NP GaN electrodes for electrolysis, water splitting, or photosynthetic process applications.

  9. Digital Devices, Distraction, and Student Performance: Does In-Class Cell Phone Use Reduce Learning?

    Science.gov (United States)

    Duncan, Douglas K.; Hoekstra, Angel R.; Wilcox, Bethany R.

    2012-01-01

    The recent increase in use of digital devices such as laptop computers, iPads, and web-enabled cell phones has generated concern about how technologies affect student performance. Combining observation, survey, and interview data, this research assesses the effects of technology use on student attitudes and learning. Data were gathered in eight…

  10. Photovoltaic material and device measurements workshop: focus on polycrystalline thin film cells

    Energy Technology Data Exchange (ETDEWEB)

    None

    1979-01-01

    The general purpose of the workshop was to accelerate the development of thin film solar cells by improving the versatility and reliability of material and device measurement techniques. Papers were presented under the following sessions: structural/chemical session; optical/electro-optical session; charge transport session; and poster session. Each paper was processed for EDB.

  11. Thymic Selection of T Cells as Diffusion with Intermittent Traps

    Science.gov (United States)

    Košmrlj, Andrej

    2011-04-01

    T cells orchestrate adaptive immune responses by recognizing short peptides derived from pathogens, and by distinguishing them from self-peptides. To ensure the latter, immature T cells (thymocytes) diffuse within the thymus gland, where they encounter an ensemble of self-peptides presented on (immobile) antigen presenting cells. Potentially autoimmune T cells are eliminated if the thymocyte binds sufficiently strongly with any such antigen presenting cell. We model thymic selection of T cells as a random walker diffusing in a field of immobile traps that intermittently turn "on" and "off". The escape probability of potentially autoimmune T cells is equivalent to the survival probability of such a random walker. In this paper we describe the survival probability of a random walker on a d-dimensional cubic lattice with randomly placed immobile intermittent traps, and relate it to the result of a well-studied problem where traps are always "on". Additionally, when switching between the trap states is slow, we find a peculiar caging effect for the survival probability.

  12. Selective inhibition of glial cell metabolism in vivo by fluorocitrate.

    Science.gov (United States)

    Hassel, B; Paulsen, R E; Johnsen, A; Fonnum, F

    1992-03-27

    The effect of fluorocitrate on glial and neuronal amino acid metabolism was studied. One nmol of fluorocitrate administered intrastriatally in the rat caused a 95% reduction of glutamine formation from [14C]acetate, a substrate which enters the glial cells selectively. The metabolism of [14C]glucose which enters neurons, was unaffected by fluorocitrate treatment except for the glutamine formation. This is evidence that fluorocitrate is a selective inhibitor of the glial Krebs' cycle. [14C]Citrate and 2-oxoglutarate labelled amino acids in a manner similar to [14C]acetate, which shows that these substrates are taken up and metabolized by glial cells. Differences in the labelling of gamma-aminobutyric acid (GABA) from [14C]acetate and citrate suggest that astrocytes associated with GABAergic and glutamatergic nerve terminals may differ in their preference for amino acid precursors.

  13. PARP Inhibition by Flavonoids Induced Selective Cell Killing to BRCA2-Deficient Cells

    Directory of Open Access Journals (Sweden)

    Cathy Su

    2017-10-01

    Full Text Available High consumption of dietary flavonoids might contribute to a reduction of cancer risks. Quercetin and its glycosides have PARP inhibitory effects and can induce selective cytotoxicity in BRCA2-deficient cells by synthetic lethality. We hypothesized that common flavonoids in diet naringenin, hesperetin and their glycosides have a similar structure to quercetin, which might have comparable PARP inhibitory effects, and can induce selective cytotoxicity in BRCA2-deficient cells. We utilized Chinese hamster V79 wild type, V-C8 BRCA2-deficient and its gene-complemented cells. In vitro analysis revealed that both naringenin and hesperetin present a PARP inhibitory effect. This inhibitory effect is less specific than for quercetin. Hesperetin was more cytotoxic to V79 cells than quercetin and naringenin based on colony formation assay. Quercetin and naringenin killed V-C8 cells with lower concentrations, and presented selective cytotoxicity to BRCA2-deficient cells. However, the cytotoxicity of hesperetin was similar among all three cell lines. Glycosyl flavonoids, isoquercetin and rutin as well as naringin showed selective cytotoxicity to BRCA2-deficient cells; hesperidin did not. These results suggest that flavonoids with the PARP inhibitory effect can cause synthetic lethality to BRCA2-deficient cells when other pathways are not the primary cause of death.

  14. Peptide fibrils with altered stability, activity, and cell selectivity

    OpenAIRE

    Chen, Long; Liang, Jun F.

    2013-01-01

    Peptides have some unique and superior features compared to proteins. However, the use of peptides as therapeutics is hampered by their low stability and cell selectivity. In this study, a new lytic peptide (CL-1, FLGALFRALSRLL) was constructed. Under the physiological condition, peptide CL-1 self-assembled into dynamically stable aggregates with fibrils-like structures. Aggregated CL-1 demonstrated dramatically altered activity and stability in comparison with single molecule CL-1 and other ...

  15. Cell adsorption and selective desorption for separation of microbial cells by using chitosan-immobilized silica.

    Science.gov (United States)

    Kubota, Munehiro; Matsui, Masayoshi; Chiku, Hiroyuki; Kasashima, Nobuyuki; Shimojoh, Manabu; Sakaguchi, Kengo

    2005-12-01

    Cell adsorption and selective desorption for separation of microbial cells were conducted by using chitosan-immobilized silica (CIS). When chitosan was immobilized onto silica surfaces with glutaraldehyde, bacterial cells adsorbed well and retained viability. Testing of the adsorption and desorption ability of CIS using various microbes such as Escherichia coli, Aeromonas hydrophila, Pseudomonas aeruginosa, Bacillus subtilis, Micrococcus luteus, Staphylococcus aureus, Staphylococcus epidermidis, Lactobacillus casei, Streptococcus mutans, Streptococcus sobrinus, Streptococcus salivarius, Saccharomyces cerevisiae, Saccharomyces ludwigii, and Schizosaccharomyces pombe revealed that most microbes could be adsorbed and selectively desorbed under different conditions. In particular, recovery was improved when L-cysteine was added. A mixture of two bacterial strains adsorbed onto CIS could also be successfully separated by use of specific solutions for each strain. Most of the desorbed cells were alive. Thus, quantitative and selective fractionation of cells is readily achievable by employing chitosan, a known antibacterial material.

  16. Selective in situ functionalization of biosensors on LOC devices using laminar co-flow

    DEFF Research Database (Denmark)

    Parra-Cabrera, C.; Sporer, C.; Rodriguez-Villareal, I.

    2012-01-01

    Many applications involving lab-on-a-chip (LOC) devices are prevented from entering the market because of difficulties to achieve mass production and impart suitable properties allowing long-term storage. To integrate biosensors on these microfluidic chips, one of the main restrictions is the fab...

  17. Material Selection for Dye Sensitized Solar Cells Using Multiple Attribute Decision Making Approach

    Directory of Open Access Journals (Sweden)

    Sarita Baghel

    2014-01-01

    Full Text Available Dye sensitized solar cells (DSCs provide a potential alternative to conventional p-n junction photovoltaic devices. The semiconductor thin film plays a crucial role in the working of DSC. This paper aims at formulating a process for the selection of optimum semiconductor material for nanostructured thin film using multiple attribute decision making (MADM approach. Various possible available semiconducting materials and their properties like band gap, cost, mobility, rate of electron injection, and static dielectric constant are considered and MADM technique is applied to select the best suited material. It was found that, out of all possible candidates, titanium dioxide (TiO2 is the best semiconductor material for application in DSC. It was observed that the proposed results are in good agreement with the experimental findings.

  18. How to select end user clinical data entry devices. Rush University Medical Center develops tool to identify the quantity of devices needed for the implementation of a new EMR and CPOE system.

    Science.gov (United States)

    Oder, Karl; Nauseda, Susan; Carlson, Elizabeth; Llewellyn, Jane; Brown, Fred; Catrambone, Cathy; Fogg, Louis; Garcia, Brian

    2010-01-01

    Selecting the right types and quantities of computers to support data entry to an inpatient Electronic Medical Record (EMR) can be challenging. In addition to software and hardware considerations, many other variables affect the decision including staffing levels, hospital workflows, and floor plans. Rush University Medical Center (RUMC) developed a tool to help identify the quantity of devices needed in a Patient Care Unit (PCU). RUMC successfully used the tool in selecting the quantity of devices needed for the implementation of a new EMR and Computerized Provider Order Entry (CPOE) system. This case study describes the use of the tool to determine quantities of PCU devices, the advantages and disadvantages of different types of computing devices for bedside documentation and areas that require special considerations in the selection of devices.

  19. Predicting device failure after percutaneous repair of functional mitral regurgitation in advanced heart failure: Implications for patient selection.

    Science.gov (United States)

    Stolfo, Davide; De Luca, Antonio; Morea, Gaetano; Merlo, Marco; Vitrella, Giancarlo; Caiffa, Thomas; Barbati, Giulia; Rakar, Serena; Korcova, Renata; Perkan, Andrea; Pinamonti, Bruno; Pappalardo, Aniello; Berardini, Alessandra; Biagini, Elena; Saia, Francesco; Grigioni, Francesco; Rapezzi, Claudio; Sinagra, Gianfranco

    2018-04-15

    Patients with heart failure (HF) and severe symptomatic functional mitral regurgitation (FMR) may benefit from MitraClip implantation. With increasing numbers of patients being treated the success of procedure becomes a key issue. We sought to investigate the pre-procedural predictors of device failure in patients with advanced HF treated with MitraClip. From April 2012 to November 2016, 76 patients with poor functional class (NYHA class III-IV) and severe left ventricular (LV) remodeling underwent MitraClip implantation at University Hospitals of Trieste and Bologna (Italy). Device failure was assessed according to MVARC criteria. Patients were subsequently followed to additionally assess the patient success after 12months. Mean age was 67±12years, the mean Log-EuroSCORE was 23.4±16.5%, and the mean LV end-diastolic volume index and ejection fraction (EF) were 112±33ml/m 2 and 30.6±8.9%, respectively. At short-term evaluation, device failure was observed in 22 (29%) patients. Univariate predictors of device failure were LVEF, LV and left atrial volumes and anteroposterior mitral annulus diameter. Annulus dimension (OR 1.153, 95% CI 1.002-1.327, p=0.043) and LV end-diastolic volume (OR 1.024, 95% CI 1.000-1.049, p=0.049) were the only variables independently associated with the risk of device failure at the multivariate model. Pre-procedural anteroposterior mitral annulus diameter accurately predicted the risk of device failure after MitraClip in the setting of advanced HF. Its assessment might aid the selection of the best candidates to percutaneous correction of FMR. Copyright © 2018 Elsevier B.V. All rights reserved.

  20. Passive safety device and internal short tested method for energy storage cells and systems

    Science.gov (United States)

    Keyser, Matthew; Darcy, Eric; Long, Dirk; Pesaran, Ahmad

    2015-09-22

    A passive safety device for an energy storage cell for positioning between two electrically conductive layers of the energy storage cell. The safety device also comprising a separator and a non-conductive layer. A first electrically conductive material is provided on the non-conductive layer. A first opening is formed through the separator between the first electrically conductive material and one of the electrically conductive layers of the energy storage device. A second electrically conductive material is provided adjacent the first electrically conductive material on the non-conductive layer, wherein a space is formed on the non-conductive layer between the first and second electrically conductive materials. A second opening is formed through the non-conductive layer between the second electrically conductive material and another of the electrically conductive layers of the energy storage device. The first and second electrically conductive materials combine and exit at least partially through the first and second openings to connect the two electrically conductive layers of the energy storage device at a predetermined temperature.

  1. Designing and modeling a centrifugal microfluidic device to separate target blood cells

    International Nuclear Information System (INIS)

    Shamloo, Amir; Selahi, AmirAli; Madadelahi, Masoud

    2016-01-01

    The objective of this study is to design a novel and efficient portable lab-on-a-CD (LOCD) microfluidic device for separation of specific cells (target cells) using magnetic beads. In this study the results are shown for neutrophils as target cells. However, other kinds of target cells can be separated in a similar approach. The designed microfluidics can be utilized as a point of care system for neutrophil detection. This microfluidic system employs centrifugal and magnetic forces for separation. After model validation by the experimental data in the literature (that may be used as a design tool for developing centrifugo-magnetophoretic devices), two models are presented for separation of target cells using magnetic beads. The first model consists of one container in the inlet section and two containers in the outlets. Initially, the inlet container is filled with diluted blood sample which is a mixture of red blood cells (RBCs) plus neutrophils which are attached to Magnetic beads. It is shown that by using centrifugal and magnetic forces, this model can separate all neutrophils with recovery factor of ∼100%. In the second model, due to excess of magnetic beads in usual experimental analysis (to ensure that all target cells are attached to them) the geometry is improved by adding a third outlet for these free magnetic beads. It is shown that at angular velocity of 45 rad s −1 , recovery factor of 100% is achievable for RBCs, free magnetic beads and neutrophils as target cells. (paper)

  2. Designing and modeling a centrifugal microfluidic device to separate target blood cells

    Science.gov (United States)

    Shamloo, Amir; Selahi, AmirAli; Madadelahi, Masoud

    2016-03-01

    The objective of this study is to design a novel and efficient portable lab-on-a-CD (LOCD) microfluidic device for separation of specific cells (target cells) using magnetic beads. In this study the results are shown for neutrophils as target cells. However, other kinds of target cells can be separated in a similar approach. The designed microfluidics can be utilized as a point of care system for neutrophil detection. This microfluidic system employs centrifugal and magnetic forces for separation. After model validation by the experimental data in the literature (that may be used as a design tool for developing centrifugo-magnetophoretic devices), two models are presented for separation of target cells using magnetic beads. The first model consists of one container in the inlet section and two containers in the outlets. Initially, the inlet container is filled with diluted blood sample which is a mixture of red blood cells (RBCs) plus neutrophils which are attached to Magnetic beads. It is shown that by using centrifugal and magnetic forces, this model can separate all neutrophils with recovery factor of ~100%. In the second model, due to excess of magnetic beads in usual experimental analysis (to ensure that all target cells are attached to them) the geometry is improved by adding a third outlet for these free magnetic beads. It is shown that at angular velocity of 45 rad s-1, recovery factor of 100% is achievable for RBCs, free magnetic beads and neutrophils as target cells.

  3. Evaluation of bioactivity of octacalcium phosphate using osteoblastic cell aggregates on a spheroid culture device

    Directory of Open Access Journals (Sweden)

    Takahisa Anada

    2016-03-01

    Full Text Available Much attention has been paid to three-dimensional cell culture systems in the field of regenerative medicine, since three-dimensional cellular aggregates, or spheroids, are thought to better mimic the in vivo microenvironments compared to conventional monolayer cultured cells. Synthetic calcium phosphate (CaP materials are widely used as bone substitute materials in orthopedic and dental surgeries. Here we have developed a technique for constructing a hybrid spheroid consisting of mesenchymal stem cells (MSCs and synthetic CaP materials using a spheroid culture device. We found that the device is able to generate uniform-sized CaP/cell hybrid spheroids rapidly and easily. The results showed that the extent of osteoblastic differentiation from MSCs was different when cells were grown on octacalcium phosphate (OCP, hydroxyapatite (HA, or β-tricalcium phosphate (β-TCP. OCP showed the greatest ability to increase the alkaline phosphatase activity of the spheroid cells. The results suggest that the spheroids with incorporated OCP may be an effective implantable hybrid consisting of scaffold material and cells for bone regeneration. It is also possible that this CaP–cell spheroid system may be used as an in vitro method for assessing the osteogenic induction ability of CaP materials.

  4. Collateral methotrexate resistance in cisplatin-selected murine leukemia cells

    Directory of Open Access Journals (Sweden)

    Bhushan A.

    1999-01-01

    Full Text Available Resistance to anticancer drugs is a major cause of failure of many therapeutic protocols. A variety of mechanisms have been proposed to explain this phenomenon. The exact mechanism depends upon the drug of interest as well as the tumor type treated. While studying a cell line selected for its resistance to cisplatin we noted that the cells expressed a >25,000-fold collateral resistance to methotrexate. Given the magnitude of this resistance we elected to investigate this intriguing collateral resistance. From a series of investigations we have identified an alteration in a membrane protein of the resistant cell as compared to the sensitive cells that could be the primary mechanism of resistance. Our studies reviewed here indicate decreased tyrosine phosphorylation of a protein (molecular mass = 66 in the resistant cells, which results in little or no transfer of methotrexate from the medium into the cell. Since this is a relatively novel function for tyrosine phosphorylation, this information may provide insight into possible pharmacological approaches to modify therapeutic regimens by analyzing the status of this protein in tumor samples for a better survival of the cancer patients.

  5. A new portable device for automatic controlled-gradient cryopreservation of blood mononuclear cells.

    Science.gov (United States)

    Hviid, L; Albeck, G; Hansen, B; Theander, T G; Talbot, A

    1993-01-04

    Protection of the functional integrity of mononuclear cells stored in liquid N2 requires careful control of the freezing procedure. Consequently, optimal quality of cryopreserved cells is usually assured by freezing according to a specified time-temperature gradient generated by computer-controlled freezing devices. While such equipment offers large capacity and secures maximum survival and functional integrity of the lymphocytes upon thawing, it is quite costly and strictly stationary. We have previously developed and tested an alternative, manual device for controlled-gradient lymphocyte freezing, which has proved suitable for field conditions. We report here the development and testing of a similar micro-controller regulated device, allowing unattended and automatic controlled-gradient cell freezing. The equipment exploits the temperature gradient present between the liquid N2 surface and the neck in an ordinary liquid N2 refrigerator. The lymphocyte samples are placed in a small elevator, which is moved through the N2 gas phase by a stepper motor. Time and temperature are measured at regular intervals, and the position of the samples adjusted to ensure that the actual measurements closely match encoded ideal values. Results of assays of the functional integrity and phenotypic composition of human mononuclear cells frozen by the new system were comparable to those obtained when using cells frozen by a commercially available, stationary cell-freezing equipment, or fresh autologous cell samples tested in parallel. Furthermore, there was a good correlation between functional and phenotypic data obtained using frozen and autologous fresh samples of mononuclear cells. The equipment described is low weight and has low N2 consumption, and is thus suitable for the collection and cryopreservation of lymphocytes under field conditions. Furthermore, the technique provides an inexpensive alternative for researchers with a limited requirement for the simultaneous freezing of

  6. A device for real-time live-cell microscopy during dynamic dual-modal mechanostimulation

    Science.gov (United States)

    Lorusso, D.; Nikolov, H. N.; Chmiel, T.; Beach, R. J.; Sims, S. M.; Dixon, S. J.; Holdsworth, D. W.

    2017-03-01

    Mechanotransduction - the process by which cells sense and respond to mechanical stimuli - is essential for several physiological processes including skeletal homeostasis. Mammalian cells are thought to be sensitive to different modes of mechanical stimuli, including vibration and fluid shear. To better understand the mechanisms underlying the early stages of mechanotransduction, we describe the development of devices for mechanostimulation (by vibration and fluid shear) of live cells that can be integrated with real-time optical microscopy. The integrated system can deliver up to 3 Pa of fluid shear simultaneous with high-frequency sinusoidal vibrations up to 1 g. Stimuli can be applied simultaneously or independently to cells during real-time microscopic imaging. A custom microfluidic chamber was prepared from polydimethylsiloxane on a glass-bottom cell culture dish. Fluid flow was applied with a syringe pump to induce shear stress. This device is compatible with a custom-designed motion control vibration system. A voice coil actuates the system that is suspended on linear air bushings. Accelerations produced by the system were monitored with an on-board accelerometer. Displacement was validated optically using particle tracking digital high-speed imaging (1200 frames per second). During operation at nominally 45 Hz and 0.3 g, displacements were observed to be within 3.56% of the expected value. MC3T3-E1 osteoblast like cells were seeded into the microfluidic device and loaded with the calcium sensitive fluorescent probe fura-2, then mounted onto the dual-modal mechanostimulation platform. Cells were then imaged and monitored for fluorescence emission. In summary, we have developed a system to deliver physiologically relevant vibrations and fluid shear to live cells during real-time imaging and photometry. Monitoring the behavior of live cells loaded with appropriate fluorescent probes will enable characterization of the signals activated during the initial

  7. External circuit integration with electromagnetic particle in cell modeling of plasma focus devices

    International Nuclear Information System (INIS)

    Seng, Y. S.; Lee, P.; Rawat, R. S.

    2015-01-01

    The pinch performance of a plasma focus (PF) device is sensitive to the physical conditions of the breakdown phase. It is therefore essential to model and study the initial phase in order to optimize device performance. An external circuit is self consistently coupled to the electromagnetic particle in cell code to model the breakdown and initial lift phase of the United Nations University/International Centre for Theoretical Physics (UNU-ICTP) plasma focus device. Gas breakdown during the breakdown phase is simulated successfully, following a drop in the applied voltage across the device and a concurrent substantial rise in the circuit current. As a result, the plasma becomes magnetized, with the growing value of the magnetic field over time leading to the gradual lift off of the well formed current sheath into the axial acceleration phase. This lifting off, with simultaneous outward sheath motion along the anode and vertical cathode, and the strong magnetic fields in the current sheath region, was demonstrated in this work, and hence validates our method of coupling the external circuit to PF devices. Our method produces voltage waveforms that are qualitatively similar to the observed experimental voltage profiles of the UNU-ICTP device. Values of the mean electron energy before and after voltage breakdown turned out to be different, with the values after breakdown being much lower. In both cases, the electron energy density function turned out to be non-Maxwellian

  8. A hybrid microfluidic-vacuum device for direct interfacing with conventional cell culture methods

    Directory of Open Access Journals (Sweden)

    Monuki Edwin S

    2007-09-01

    Full Text Available Abstract Background Microfluidics is an enabling technology with a number of advantages over traditional tissue culture methods when precise control of cellular microenvironment is required. However, there are a number of practical and technical limitations that impede wider implementation in routine biomedical research. Specialized equipment and protocols required for fabrication and setting up microfluidic experiments present hurdles for routine use by most biology laboratories. Results We have developed and validated a novel microfluidic device that can directly interface with conventional tissue culture methods to generate and maintain controlled soluble environments in a Petri dish. It incorporates separate sets of fluidic channels and vacuum networks on a single device that allows reversible application of microfluidic gradients onto wet cell culture surfaces. Stable, precise concentration gradients of soluble factors were generated using simple microfluidic channels that were attached to a perfusion system. We successfully demonstrated real-time optical live/dead cell imaging of neural stem cells exposed to a hydrogen peroxide gradient and chemotaxis of metastatic breast cancer cells in a growth factor gradient. Conclusion This paper describes the design and application of a versatile microfluidic device that can directly interface with conventional cell culture methods. This platform provides a simple yet versatile tool for incorporating the advantages of a microfluidic approach to biological assays without changing established tissue culture protocols.

  9. A microfluidic device integrating plasmonic nanodevices for Raman spectroscopy analysis on trapped single living cells

    KAUST Repository

    Perozziello, Gerardo

    2013-11-01

    In this work we developed a microfluidic device integrating nanoplasmonic devices combined with fluidic trapping regions. The microfuidic traps allow to capture single cells in areas where plasmonic sensors are placed. In this way it is possible to perform Enhanced Raman analysis on the cell membranes. Moreover, by changing direction of the flux it is possible to change the orientation of the cell in the trap, so that it is possible to analyze different points of the membrane of the same cell. We shows an innovative procedure to fabricate and assembly the microfluidic device which combine photolithography, focused ion beam machining, and hybrid bonding between a polymer substrate and lid of Calcium fluoride. This procedure is compatible with the fabrication of the plasmonic sensors in close proximity of the microfluidic traps. Moreover, the use of Calcium fluoride as lid allows full compatibility with Raman measurements producing negligible Raman background signal and avoids Raman artifacts. Finally, we performed Raman analysis on cells to monitor their oxidative stress under particular non physiological conditions. © 2013 Elsevier B.V. All rights reserved.

  10. Moulded interconnect device fabrication by two shot molding and lasert induced selective activation

    DEFF Research Database (Denmark)

    Sun, Jie; Hansen, Hans Nørgaard

    , comparative process analysis, applications and specially two shot injection molding and laser induced selective activation in the MID area. There is also an experimental part which contains fabrication of a MID demonstrator, selective metallization as well as characterization. The realization of molded...

  11. Temporary Mechanical Circulatory Support in Cardiac Critical Care: A State of the Art Review and Algorithm for Device Selection.

    Science.gov (United States)

    Nagpal, A Dave; Singal, Rohit K; Arora, Rakesh C; Lamarche, Yoan

    2017-01-01

    With more than 60 years of continuous development and improvement, a variety of temporary mechanical circulatory support (MCS) devices and implantation strategies exist, each with unique advantages and disadvantages. A thorough understanding of each available device is essential for optimizing patient outcomes in a fiscally responsible manner. In this state of the art review we examine the entire range of commonly available peripheral and centrally cannulated temporary MCS devices, including intra-aortic balloon pumps, the Impella (Abiomed, Danvers, MA) family of microaxial pumps, the TandemHeart (CardiacAssist Inc, Pittsburg, PA) pump and percutaneous cannulas, centrally cannulated centrifugal pumps such as the CentriMag (Thoratec Corp, Pleasanton, CA/St Jude Medical, St Paul, MN/Abbott Laboratories, Abbott Park, IL) and Rotaflow (Maquet Holding BV & Co KG, Rastatt Germany), and extracorporeal membrane oxygenation. Several factors need detailed consideration when contemplating MCS in any given patient, mandating a balanced, algorithmic approach for these sick patients. In this review we describe our approach to MCS, and emphasize the need for multidisciplinary input to consider patient-related, logistical, and institutional factors. Evidence is summarized and referenced where available, but because of the lack of high-quality evidence, current best practice is described. Future directions for investigation are discussed, which will better define patient and device selection, and optimize MCS-specific patient care protocols. Copyright © 2016 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.

  12. Selective Interlayers and Contacts in Organic Photovoltaic Cells.

    Science.gov (United States)

    Ratcliff, Erin L; Zacher, Brian; Armstrong, Neal R

    2011-06-02

    Organic photovoltaic cells (OPVs) are promising solar electric energy conversion systems with impressive recent optimization of active layers. OPV optimization must now be accompanied by the development of new charge-selective contacts and interlayers. This Perspective considers the role of interface science in energy harvesting using OPVs, looking back at early photoelectrochemical (photogalvanic) energy conversion platforms, which suffered from a lack of charge carrier selectivity. We then examine recent platforms and the fundamental aspects of selective harvesting of holes and electrons at opposite contacts. For blended heterojunction OPVs, contact/interlayer design is especially critical because charge harvesting competes with recombination at these same contacts. New interlayer materials can modify contacts to both control work function and introduce selectivity and chemical compatibility with nonpolar active layers and add thermodynamic and kinetic selectivity to charge harvesting. We briefly discuss the surface and interface science required for the development of new interlayer materials and take a look ahead at the challenges yet to be faced in their optimization.

  13. Thermocouple-based Temperature Sensing System for Chemical Cell Inside Micro UAV Device

    Science.gov (United States)

    Han, Yanhui; Feng, Yue; Lou, Haozhe; Zhang, Xinzhao

    2018-03-01

    Environmental temperature of UAV system is crucial for chemical cell component inside. Once the temperature of this chemical cell is over 259 °C and keeps more than 20 min, the high thermal accumulation would result in an explosion, which seriously damage the whole UAV system. Therefore, we develop a micro temperature sensing system for monitoring the temperature of chemical cell thermally influenced by UAV device deployed in a 300 °C temperature environment, which is quite useful for insensitive munitions and UAV safety enhancement technologies.

  14. Continuum and KMC simulations of realistic bulk heterostructure solar cell photovoltaic devices

    Science.gov (United States)

    Pimcharoen, Kanokkorn; Olds, Daniel; Duxbury, Phillip

    2011-03-01

    Design of novel solar cell architectures is significantly assisted by reliable continuum device models, and computational methods capable of solving these models in one, two and three dimensions. We are developing computational methods for these models and are validating them using Kinetic Monte Carlo simulations in the same morphologies. We present simulations using idealized morphologies to test approximations in the continuum models, and we present results for bulk heterostructure morphologies deduced by refining digital nanostructures to experimental neutron relectometry and small angle scattering data. In particular we discuss the ability of one dimensional device models to capture the physics of photovoltaic response of realistic bulk heterostructures.

  15. Modelling organs, tissues, cells and devices using Matlab and Comsol multiphysics

    CERN Document Server

    Dokos, Socrates

    2017-01-01

    This book presents a theoretical and practical overview of computational modeling in bioengineering, focusing on a range of applications including electrical stimulation of neural and cardiac tissue, implantable drug delivery, cancer therapy, biomechanics, cardiovascular dynamics, as well as fluid-structure interaction for modelling of organs, tissues, cells and devices. It covers the basic principles of modeling and simulation with ordinary and partial differential equations using MATLAB and COMSOL Multiphysics numerical software. The target audience primarily comprises postgraduate students and researchers, but the book may also be beneficial for practitioners in the medical device industry.

  16. METHOD OF PHYSIOTHERAPY MEDICAL PROCEDURES FOR THERMAL IMPACT ON SELECTED AREAS WITH HUMAN HANDS THERMOELECTRIC DEVICES

    Directory of Open Access Journals (Sweden)

    A. B. Sulin

    2015-01-01

    Full Text Available The device for thermal impact on separate zones of a hand of the person executed on the basis of thermoelectric converters of energy is considered. The advantages consisting in high environmental friendliness, noiselessness, reliability, functionality, universality are noted it. The technique of carrying out medical (preventive physiotherapeutic procedures, the hands of the person consisting in contrast thermal impact on a site with various level of heating and cooling, and also lasting expositions is described.

  17. Laser Direct Writing and Selective Metallization of Metallic Circuits for Integrated Wireless Devices.

    Science.gov (United States)

    Cai, Jinguang; Lv, Chao; Watanabe, Akira

    2018-01-10

    Portable and wearable devices have attracted wide research attention due to their intimate relations with human daily life. As basic structures in the devices, the preparation of high-conductive metallic circuits or micro-circuits on flexible substrates should be facile, cost-effective, and easily integrated with other electronic units. In this work, high-conductive carbon/Ni composite structures were prepared by using a facile laser direct writing method, followed by an electroless Ni plating process, which exhibit a 3-order lower sheet resistance of less than 0.1 ohm/sq compared to original structures before plating, showing the potential for practical use. The carbon/Ni composite structures exhibited a certain flexibility and excellent anti-scratch property due to the tight deposition of Ni layers on carbon surfaces. On the basis of this approach, a wireless charging and storage device on a polyimide film was demonstrated by integrating an outer rectangle carbon/Ni composite coil for harvesting electromagnetic waves and an inner carbon micro-supercapacitor for energy storage, which can be fast charged wirelessly by a commercial wireless charger. Furthermore, a near-field communication (NFC) tag was prepared by combining a carbon/Ni composite coil for harvesting signals and a commercial IC chip for data storage, which can be used as an NFC tag for practical application.

  18. Comparative analysis of selected exhaled breath biomarkers obtained with two different temperature-controlled devices

    Directory of Open Access Journals (Sweden)

    Brüning Thomas

    2009-11-01

    Full Text Available Abstract Background The collection of exhaled breath condensate (EBC is a suitable and non-invasive method for evaluation of airway inflammation. Several studies indicate that the composition of the condensate and the recovery of biomarkers are affected by physical characteristics of the condensing device and collecting circumstances. Additionally, there is an apparent influence of the condensing temperature, and often the level of detection of the assay is a limiting factor. The ECoScreen2 device is a new, partly single-use disposable system designed for studying different lung compartments. Methods EBC samples were collected from 16 healthy non-smokers by using the two commercially available devices ECoScreen2 and ECoScreen at a controlled temperature of -20°C. EBC volume, pH, NOx, LTB4, PGE2, 8-isoprostane and cys-LTs were determined. Results EBC collected with ECoScreen2 was less acidic compared to ECoScreen. ECoScreen2 was superior concerning condensate volume and detection of biomarkers, as more samples were above the detection limit (LTB4 and PGE2 or showed higher concentrations (8-isoprostane. However, NOx was detected only in EBC sampled by ECoScreen. Conclusion ECoScreen2 in combination with mediator specific enzyme immunoassays may be suitable for measurement of different biomarkers. Using this equipment, patterns of markers can be assessed that are likely to reflect the complex pathophysiological processes in inflammatory respiratory disease.

  19. A microfluidic device for separation of amniotic fluid mesenchymal stem cells utilizing louver-array structures.

    Science.gov (United States)

    Wu, Huei-Wen; Lin, Xi-Zhang; Hwang, Shiaw-Min; Lee, Gwo-Bin

    2009-12-01

    Human mesenchymal stem cells can differentiate into multiple lineages for cell therapy and, therefore, have attracted considerable research interest recently. This study presents a new microfluidic device for bead and cell separation utilizing a combination of T-junction focusing and tilted louver-like structures. For the first time, a microfluidic device is used for continuous separation of amniotic stem cells from amniotic fluids. An experimental separation efficiency as high as 82.8% for amniotic fluid mesenchymal stem cells is achieved. Furthermore, a two-step separation process is performed to improve the separation efficiency to 97.1%. These results are based on characterization experiments that show that this microfluidic chip is capable of separating beads with diameters of 5, 10, 20, and 40 microm by adjusting the volume-flow-rate ratio between the flows in the main and side channels of the T-junction focusing structure. An optimal volume-flow-rate ratio of 0.5 can lead to high separation efficiencies of 87.8% and 85.7% for 5-microm and 10-microm beads, respectively, in a one-step separation process. The development of this microfluidic chip may be promising for future research into stem cells and for cell therapy.

  20. Device to position selectively a tool carried by a vehicle moving on the perforated plate of a tube bundle

    International Nuclear Information System (INIS)

    Bernardin, M.

    1985-01-01

    The aim of the invention is an examination device for a tube bundle of an apparatus such as, but not restrictively, a steam generator, situated in a dangerous zone, e.g. radioactive and designed to be introduced into the water box of the said and placed against the perforated plate of the tube bundle by an operator working outside of the said apparatus and able to operate whatever the vertical or horizontal position of the tube plate. The device has a selectively positionable tool - carrying vehicle comprising pistons positioning fingers extendable into the tubes and mounted on extendable supports perpendicular to the pistons and to each other, and an articulated telescopic arm fixed at one end to a rotary mounting on the vehicle and at the other end to an access opening in the vessel containing the tube plate, to hold the vehicle against the plate [fr

  1. Recommended safety procedures for the selection and use of demonstration-type gas discharge devices in schools

    International Nuclear Information System (INIS)

    1979-01-01

    A 1972 survey of 30 Ottawa secondary schools revealed a total of 347 actual or potential X-ray sources available in these schools. More than half of these sources were gas discharge tubes. Some gas discharge tubes, in particular the cold cathode type, can emit X-rays at significantly high levels. Unless such tubes are used carefully, and with regard for good radiation safety practices, they can result in exposures to students that are in excess of the maximum levels recommended by the International Commission on Radiological Protection. Several cases of the recommended dose being exceeded were found in the classes surveyed. This document has been prepared to assist science teachers and others using demonstration-type gas discharge devices to select and use such devices so as to present negligible risk to themselves and students. Useful information on safety procedures to be followed when performing demonstrations or experiments is included. (J.T.A.)

  2. Selection of aptamers for Candida albicans by cell-SELEX

    International Nuclear Information System (INIS)

    Miranda, Alessandra Nunes Duarte

    2017-01-01

    The growing concern with invasive fungal infections, responsible for an alarming mortality rate of immunosuppressed patients and in Intensive Care Units, evidences the need for a fast and specific method for the Candida albicans detection, since this species is identified as one of the main causes of septicemia. Commonly, it is a challenge for clinicians to determine the primary infection foci, the dissemination degree, or whether the site of a particular surgery is involved. Although scintigraphic imaging represents a promising tool for infectious foci detection, it still lacks a methodology for C. albicans diagnosis due to the absence of specific radiotracers for this microorganism. Aptamers are molecules that have almost ideal properties for use as diagnostic radiopharmaceuticals, such as high specificity for their molecular targets, lack of immunogenicity and toxicity, high tissue penetration and rapid blood clearance. Aptamers can also be labeled with different radionuclides. This work aims to obtain aptamers for specific binding to C. albicans cells for future application as a radiopharmaceutical. It was used a variation of the SELEX (Systematic Evolution of Ligands by EXponential Enrichment) technique, termed cell-SELEX, in which cells are the targets for selection. A selection protocol was standardized using a random library of single-stranded oligonucleotides, each containing two fixed regions flanking a sequence of 40 random nucleotides. This library was incubated with C. albicans cells in the presence of competitors. Then, the binding sequences were separated by centrifugation, resuspended and amplified by PCR. The amplification was confirmed by agarose gel electrophoresis. After that, the ligands were purified to obtain a new pool of ssDNA, from which a new incubation was carried out. The selection parameters were gradually modified in order to increase stringency. This cycle was repeated 12 times to allow the selection of sequences with the maximum

  3. Immuno Nanoparticles Integrated Electrical Control of Targeted Cancer Cell Development Using Whole Cell Bioelectronic Device

    Science.gov (United States)

    Hondroulis, Evangelia; Zhang, Rui; Zhang, Chengxiao; Chen, Chunying; Ino, Kosuke; Matsue, Tomokazu; Li, Chen-Zhong

    2014-01-01

    Electrical properties of cells determine most of the cellular functions, particularly ones which occur in the cell's membrane. Manipulation of these electrical properties may provide a powerful electrotherapy option for the treatment of cancer as cancerous cells have been shown to be more electronegative than normal proliferating cells. Previously, we used an electrical impedance sensing system (EIS) to explore the responses of cancerous SKOV3 cells and normal HUVEC cells to low intensity (electrotherapy for clinical and drug delivery applications. PMID:25057316

  4. Induction and selection of Sox17-expressing endoderm cells generated from murine embryonic stem cells.

    Science.gov (United States)

    Schroeder, Insa S; Sulzbacher, Sabine; Nolden, Tobias; Fuchs, Joerg; Czarnota, Judith; Meisterfeld, Ronny; Himmelbauer, Heinz; Wobus, Anna M

    2012-01-01

    Embryonic stem (ES) cells offer a valuable source for generating insulin-producing cells. However, current differentiation protocols often result in heterogeneous cell populations of various developmental stages. Here we show the activin A-induced differentiation of mouse ES cells carrying a homologous dsRed-IRES-puromycin knock-in within the Sox17 locus into the endoderm lineage. Sox17-expressing cells were selected by fluorescence-assisted cell sorting (FACS) and characterized at the transcript and protein level. Treatment of ES cells with high concentrations of activin A for 10 days resulted in up to 19% Sox17-positive cells selected by FACS. Isolated Sox17-positive cells were characterized by defini- tive endoderm-specific Sox17/Cxcr4/Foxa2 transcripts, but lacked pluripotency-associated Oct4 mRNA and protein. The Sox17-expressing cells showed downregulation of extraembryonic endoderm (Sox7, Afp, Sdf1)-, mesoderm (Foxf1, Meox1)- and ectoderm (Pax6, NeuroD6)-specific transcripts. The presence of Hnf4α, Hes1 and Pdx1 mRNA demonstrated the expression of primitive gut/foregut cell-specific markers. Ngn3, Nkx6.1 and Nkx2.2 transcripts in Sox17-positive cells were determined as properties of pancreatic endocrine progenitors. Immunocytochemistry of activin A-induced Sox17-positive embryoid bodies revealed coexpression of Cxcr4 and Foxa2. Moreover, the histochemical demonstration of E-cadherin-, Cxcr4-, Sox9-, Hnf1β- and Ngn3-positive epithelial-like structures underlined the potential of Sox17-positive cells to further differentiate into the pancreatic lineage. By reducing the heterogeneity of the ES cell progeny, Sox17-expressing cells are a suitable model to evaluate the effects of growth and differentiation factors and of culture conditions to delineate the differentiation process for the generation of pancreatic cells in vitro. Copyright © 2011 S. Karger AG, Basel.

  5. Deformation of filamentous Escherichia coli cells in a microfluidic device: a new technique to study cell mechanics.

    Directory of Open Access Journals (Sweden)

    Yaron Caspi

    Full Text Available The mechanical properties of bacterial cells are determined by their stress-bearing elements. The size of typical bacterial cells, and the fact that different time and length scales govern their behavior, necessitate special experimental techniques in order to probe their mechanical properties under various spatiotemporal conditions. Here, we present such an experimental technique to study cell mechanics using hydrodynamic forces in a microfluidic device. We demonstrate the application of this technique by calculating the flexural rigidity of non-growing Escherichia coli cells. In addition, we compare the deformation of filamentous cells under growing and non-growing conditions during the deformation process. We show that, at low forces, the force needed to deform growing cells to the same extent as non-growing cells is approximately two times smaller. Following previous works, we interpret these results as the outcome of the difference between the elastic response of non-growing cells and the plastic-elastic response of growing cells. Finally, we observe some heterogeneity in the response of individual cells to the applied force. We suggest that this results from the individuality of different bacterial cells.

  6. Selective emitter using porous silicon for crystalline silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Inyong; Kim, Kyunghae; Kim, Youngkuk; Han, Kyumin; Kyeong, Doheon; Kwon, Taeyoung; Vinh Ai, Dao; Lee, Jeongchul; Yi, Junsin [School of Information and Communication Engineering, Sungkyunkwan University, Chunchun-dong, Jangan-Gu, Suwon-City, Kyunggi-Do 440-746 (Korea); Thamilselvan, M. [School of Information and Communication Engineering, Sungkyunkwan University, Chunchun-dong, Jangan-Gu, Suwon-City, Kyunggi-Do 440-746 (Korea); Government College of Technology, Coimbatore, Tamilnadu (India); Ju, Minkyu; Lee, Kyungsoo [KPE Ins. Chunchun-dong, Jangan-Gu, Suwon-City, Kyunggi-Do 440-746 (Korea)

    2009-06-15

    This study is devoted to the formation of high-low-level-doped selective emitter for crystalline silicon solar cells for photovoltaic application. We report here the formation of porous silicon under chemical reaction condition. The chemical mixture containing hydrofluoric and nitric acid, with de-ionized water, was used to make porous on the half of the silicon surface of size 125 x 125 cm. Porous and non-porous areas each share half of the whole silicon surface. H{sub 3}PO{sub 4}:methanol gives the best deposited layer with acceptable adherence and uniformity on the non-porous and porous areas of the silicon surface to get high- and low-level-doped regions. The volume concentration of H{sub 3}PO{sub 4} does not exceed 10% of the total volume emulsion. Phosphoric acid was used as an n-type doping source to make emitter for silicon solar cells. The measured emitter sheet resistances at the high- and low-level-doped regions were 30-35 and 97-474 {omega}/{open_square} respectively. A simple process for low- and high-level doping has been achieved by forming porous and porous-free silicon surface, in this study, which could be applied for solar cells selective emitter doping. (author)

  7. Selective removal of carbon dioxide contained in the effluent from ion chromatography suppressors using a new non-vacuum device.

    Science.gov (United States)

    Masunaga, Hiroto; Higo, Yuji; Ishii, Mizuo; Maruyama, Noboru; Yamazaki, Shigeo

    2015-05-01

    In this paper, a new CO2 gas removal device optimized to selectively remove CO2 gas contained in the effluent from suppressors used in ion chromatography (IC) under non-vacuum conditions is described. This device consists of a closed vessel equipped with gas permeable tubing (GPT) and a CO2 adsorbent. During operation, the CO2 adsorbent adsorbs CO2 gas in the vessel, creating CO2 partial pressure difference between the inside of the GPT and the vessel. The CO2 gas contained in the effluent being pumped into the GPT is selectively removed from the effluent based on the diffusion of the CO2 associated with the CO2 partial pressure difference. The purpose of this study is to optimize the IC operating conditions with the aim of selectively removing HCO3(-) (CO3(2-)) contained in the effluent and reducing the electrical conductivity of the effluent under non-vacuum conditions. The electrical conductivity of the effluent and the signal intensity of the water dip is decreased by approximately 25 μS/cm (from 30 to 5 μS/cm) and by approximately twentieth, respectively, using the optimized CO2 remover. In addition, the anion detection limit achieved in IC instruments with a CO2 remover is on the order of a few ppb. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. RETRACTED: Advances in colloidal quantum dot solar cells: The depleted-heterojunction device

    KAUST Repository

    Kramer, Illan J.

    2011-08-01

    Colloidal quantum dot (CQD) photovoltaics combine low-cost solution processibility with quantum size-effect tunability to match absorption with the solar spectrum. Recent advances in CQD photovoltaics have led to 3.6% AM1.5 solar power conversion efficiencies. Here we report CQD photovoltaic devices on transparent conductive oxides and show that our devices rely on the establishment of a depletion region for field-driven charge transport and separation. The resultant depleted-heterojunction solar cells provide a 5.1% AM1.5 power conversion efficiency. The devices employ infrared-bandgap size-effect-tuned PbS colloidal quantum dots, enabling broadband harvesting of the solar spectrum. © 2010 Elsevier B.V.

  9. Electrical Impedance Spectroscopy for Detection of Cells in Suspensions Using Microfluidic Device with Integrated Microneedles

    Directory of Open Access Journals (Sweden)

    Muhammad Asraf Mansor

    2017-02-01

    Full Text Available In this study, we introduce novel method of flow cytometry for cell detection based on impedance measurements. The state of the art method for impedance flow cytometry detection utilizes an embedded electrode in the microfluidic to perform measurement of electrical impedance of the presence of cells at the sensing area. Nonetheless, this method requires an expensive and complicated electrode fabrication process. Furthermore, reuse of the fabricated electrode also requires an intensive and tedious cleaning process. Due to that, we present a microfluidic device with integrated microneedles. The two microneedles are placed at the half height of the microchannel for cell detection and electrical measurement. A commercially-available Tungsten needle was utilized for the microneedles. The microneedles are easily removed from the disposable PDMS (Polydimethylsiloxane microchannel and can be reused with a simple cleaning process, such as washing by ultrasonic cleaning. Although this device was low cost, it preserves the core functionality of the sensor, which is capable of detecting passing cells at the sensing area. Therefore, this device is suitable for low-cost medical and food safety screening and testing process in developing countries.

  10. Fabrication and characterization of a cell electrostimulator device combining physical vapor deposition and laser ablation

    Science.gov (United States)

    Aragón, Angel L.; Pérez, Eliseo; Pazos, Antonio; Bao-Varela, Carmen; Nieto, Daniel

    2017-08-01

    In this work we present the process of fabrication and optimization of a prototype of a cell electrostimulator device for medical application combining physical vapor deposition and laser ablation. The fabrication of the first prototype begins with a deposition of a thin layer of 200 nm of aluminium on a borosilicate glass substrate using physical vapor deposition (PVD). In the second stage the geometry design of the electrostimulator is made in a CAD-like software available in a Nd:YVO4 Rofin Power line 20E, operating at the fundamental wavelength of 1064 nm and 20 ns pulse width. Choosing the proper laser parameters the negative of the electrostimulator desing is ablated. After that the glass is assembled between two polycarbonate sheets and a thick sheet of polydimethylsiloxane (PDMS). The PDMS sheet has a round hole in where cells are placed. There is also included a thin soda-lime silicate glass (100 μm) between the electrostimulator and the PMDS to prevent the cells for being in contact with the electric circuit. In order to control the electrical signal applied to the electrostimulator is used a digital I/O device from National Instruments (USB-6501) which provides 5 V at the output monitored by a software programmed in LabVIEW. Finally, the optical and electrical characterization of the cell electrostimulator device is presented.

  11. Bioenergy conversion and storage systems: from conventional electrochemical cells to hybrid bioelectronic devices

    DEFF Research Database (Denmark)

    Pankratov, Dmitrii; Chi, Qijin

    2017-01-01

    The rapid development and popularization of wearable and implantable self-sustainable electronics has increasingly demanded new-generation miniature and biocompatible power systems that can function under near-neutral pH solution and ambient conditions. Towards this end, enzymatic fuel cells (EFCs......) using biocatalysts can offer an effective alternative to conventional batteries or fuel cells attributed to high biocatalytic activity, substrate specified selectivity, and non-toxic end products with ecofriendly impacts. Newly emerging photobioelectrochemical cells (PBCs), exploiting photosynthetic...

  12. Integration of Rabbit Adipose Derived Mesenchymal Stem Cells to Hydroxyapatite Burr Hole Button Device for Bone Interface Regeneration

    Directory of Open Access Journals (Sweden)

    Viswanathan Gayathri

    2016-01-01

    Full Text Available Adipose Derived Mesenchymal Stem Cells, multipotent stem cells isolated from adipose tissue, present close resemblance to the natural in vivo milieu and microenvironment of bone tissue and hence widely used for in bone tissue engineering applications. The present study evaluates the compatibility of tissue engineered hydroxyapatite burr hole button device (HAP-BHB seeded with Rabbit Adipose Derived Mesenchymal Stem Cells (ADMSCs. Cytotoxicity, oxidative stress response, apoptotic behavior, attachment, and adherence of adipose MSC seeded on the device were evaluated by scanning electron and confocal microscopy. The results of the MTT (3-(4,5-dimethylthiazol-2,5-diphenyl tetrazolium bromide assay indicated that powdered device material was noncytotoxic up to 0.5 g/mL on cultured cells. It was also observed that oxidative stress related reactive oxygen species production and apoptosis on cell seeded device were similar to those of control (cells alone except in 3-day period which showed increased reactive oxygen species generation. Further scanning electron and confocal microscopy indicated a uniform attachment of cells and viability up to 200 μm deep inside the device, respectively. Based on the results, it can be concluded that the in-house developed HAP-BHB device seeded with ADMSCs is nontoxic/safe compatible device for biomedical application and an attractive tissue engineered device for calvarial defect regeneration.

  13. Reversible energy storage on a fuel cell-supercapacitor hybrid device

    Energy Technology Data Exchange (ETDEWEB)

    Zerpa Unda, Jesus Enrique

    2011-02-18

    A new concept of energy storage based on hydrogen which operates reversibly near ambient conditions and without important energy losses is investigated. This concept involves the hybridization between a proton exchange membrane fuel cell and a supercapacitor. The main idea consists in the electrochemical splitting of hydrogen at a PEM fuel cell-type electrode into protons and electrons and then in the storage of these two species separately in the electrical double layer of a supercapacitor-type electrode which is made of electrically conductive large-surface area carbon materials. The investigation of this concept was performed first using a two-electrode fuel cell-supercapacitor hybrid device. A three-electrode hybrid cell was used to explore the application of this concept as a hydrogen buffer integrated inside a PEM fuel cell to be used in case of peak power demand. (orig.)

  14. Development of dielectrophoresis MEMS device for PC12 cell patterning to elucidate nerve-network generation

    Science.gov (United States)

    Nakamachi, Eiji; Koga, Hirotaka; Morita, Yusuke; Yamamoto, Koji; Sakamoto, Hidetoshi

    2018-01-01

    We developed a PC12 cell trapping and patterning device by combining the dielectrophoresis (DEP) methodology and the micro electro mechanical systems (MEMS) technology for time-lapse observation of morphological change of nerve network to elucidate the generation mechanism of neural network. We succeeded a neural network generation, which consisted of cell body, axon and dendrites by using tetragonal and hexagonal cell patterning. Further, the time laps observations was carried out to evaluate the axonal extension rate. The axon extended in the channel and reached to the target cell body. We found that the shorter the PC12 cell distance, the less the axonal connection time in both tetragonal and hexagonal structures. After 48 hours culture, a maximum success rate of network formation was 85% in the case of 40 μm distance tetragonal structure.

  15. Radiographic implications of procedures involving cardiac implantable electronic devices (CIEDs – Selected aspects

    Directory of Open Access Journals (Sweden)

    Roman Steckiewicz

    2017-06-01

    Full Text Available Background: Some cardiac implantable electronic device (CIED implantation procedures require the use of X-rays, which is reflected by such parameters as total fluoroscopy time (TFT and dose-area product (DAP – defined as the absorbed dose multiplied by the area irradiated. Material and Methods: This retrospective study evaluated 522 CIED implantation (424 de novo and 98 device upgrade and new lead placement procedures in 176 women and 346 men (mean age 75±11 years over the period 2012–2015. The recorded procedure-related parameters TFT and DAP were evaluated in the subgroups specified below. The group of 424 de novo procedures included 203 pacemaker (PM and 171 implantable cardioverter-defibrillator (ICD implantation procedures, separately stratified by single-chamber and dual-chamber systems. Another subgroup of de novo procedures involved 50 cardiac resynchronization therapy (CRT devices. The evaluated parameters in the group of 98 upgrade procedures were compared between 2 subgroups: CRT only and combined PM and ICD implantation procedures. Results: We observed differences in TFT and DAP values between procedure types, with PM-related procedures showing the lowest, ICD – intermediate (with values for single-chamber considerably lower than those for dual-chamber systems and CRT implantation procedures – highest X-ray exposure. Upgrades to CRT were associated with 4 times higher TFT and DAP values in comparison to those during other upgrade procedures. Cardiac resynchronization therapy de novo implantation procedures and upgrades to CRT showed similar mean values of these evaluated parameters. Conclusions: Total fluoroscopy time and DAP values correlated progressively with CIED implantation procedure complexity, with CRT-related procedures showing the highest values of both parameters. Med Pr 2017;68(3:363–374

  16. Quantum efficiency as a device-physics interpretation tool for thin-film solar cells

    Science.gov (United States)

    Nagle, Timothy J.

    2007-12-01

    Thin-film solar cells made from CdTe and CIGS p-type absorbers are promising candidates for generating pollution-free electricity. The challenge faced by the thin-film photovoltaics (PV) community is to improve the electrical properties of devices, without straying from low-cost, industry-friendly techniques. This dissertation will focus on the use of quantum-efficiency (QE) measurements to deduce the device physics of thin-film devices, in the hope of improving electrical properties and efficiencies of PV materials. Photons which are absorbed, but not converted into electrical energy can modify the energy bands in the solar cell. Under illumination, photoconductivity in the CdS window layer can result in bands different from those in the dark. QE data presented here was taken under a variety of light-bias conditions. These results suggest that 0.10 sun of white-light bias incident on the CdS layer is usually sufficient to achieve accurate QE results. QE results are described by models based on carrier collection by drift and diffusion, and photon absorption. These models are sensitive to parameters such as carrier mobility and lifetime. Comparing calculated QE curves with experiments, it was determined that electron lifetimes in CdTe are less than 0.1 ns. Lifetime determinations also suggest that copper serves as a recombination center in CdTe. The spatial uniformity of QE results has been investigated with the LBIC apparatus, and several experiments are described which investigate cell uniformity. Electrical variations that occur in solar cells often occur in a nonuniform fashion, and can be detected with the LBIC apparatus. Studies discussed here include investigation of patterned deposition of Cu in back-contacts, the use of high-resistivity TCO layers to mitigate nonuniformity, optical effects, and local shunts. CdTe devices with transparent back contacts were also studied with LBIC, including those that received a strong bromine/dichrol/hydrazine (BDH) etch

  17. The feasibility of using particle-in-cell technique for modeling liquid crystal devices

    Science.gov (United States)

    Leung, Wing Ching

    1997-12-01

    Liquid crystal materials are used in a variety of electronic devices, but the dynamical behavior of such devices is still not clearly understood. The primary reason for this is that there is a lack of rigorous models for a theoretical treatment for the devices. For the first time we demonstrate here the feasibility of treating such liquid crystal devices using the particle- in-cell (PIC) simulation technique. In a PIC simulation model, the liquid crystal medium is represented by a certain number of particles, each particle representing a fairly large number of real molecules in the medium. The dynamical behavior of the medium is obtained by solving the equations of motions of the particles in self- consistent appropriate fields. The motions may include both translation (flow) and rotation. By neglecting the translational motion and the conductive effects of the materials in this first innovative effort, 1- and 2- dimensional PIC codes, including viscous, electric, and elastic torques affecting the rotation of molecules, are developed for modeling a parallel-plate capacitor cell filled with a nematic liquid crystal material. Using these codes we reproduce the well known phenomenon of Fredericksz transition. Our simulations yield results in excellent agreement with the available analytical results on the threshold voltage for the Fredericksz transition. In addition, we are able to reveal the dynamical behavior of liquid crystal molecules in the device as the material undergoes the Fredericksz transition in response to an applied voltage across the liquid crystal cell. By using the 2-dimensional PIC code to simulate a segmented electrode cell, like those used in liquid crystal devices for optical gratings, the simulation results show the formation and dynamics of the defect walls. The defect wall joins the regions of the material having topologically different orientations. We found that the defect wall is associated with a large gradient in the polarization vector P

  18. A size selective nanoparticle collection device based on diffusion and thermophoresis

    International Nuclear Information System (INIS)

    Lyyraenen, Jussi; Backman, Ulrika; Tapper, Unto; Auvinen, Ari; Jokiniemi, Jorma

    2009-01-01

    There is a growing industry fabricating products that are based on nanoparticles (particle diameter d p ≤100 nm). The production of these particles requires detection, classification and characterisation of even smaller particles because of, e.g. preventing unwanted particle emissions from the processes and health issues. Monitoring of the processes is needed on one hand for product quality determinations, on the other hand to ensure safe and particle-free working conditions. Thus simple, fast and reliable measurement devices are needed for particle characterisation.

  19. Direction selectivity in a model of the starburst amacrine cell.

    Science.gov (United States)

    Tukker, John J; Taylor, W Rowland; Smith, Robert G

    2004-01-01

    The starburst amacrine cell (SBAC), found in all mammalian retinas, is thought to provide the directional inhibitory input recorded in On-Off direction-selective ganglion cells (DSGCs). While voltage recordings from the somas of SBACs have not shown robust direction selectivity (DS), the dendritic tips of these cells display direction-selective calcium signals, even when gamma-aminobutyric acid (GABAa,c) channels are blocked, implying that inhibition is not necessary to generate DS. This suggested that the distinctive morphology of the SBAC could generate a DS signal at the dendritic tips, where most of its synaptic output is located. To explore this possibility, we constructed a compartmental model incorporating realistic morphological structure, passive membrane properties, and excitatory inputs. We found robust DS at the dendritic tips but not at the soma. Two-spot apparent motion and annulus radial motion produced weak DS, but thin bars produced robust DS. For these stimuli, DS was caused by the interaction of a local synaptic input signal with a temporally delayed "global" signal, that is, an excitatory postsynaptic potential (EPSP) that spread from the activated inputs into the soma and throughout the dendritic tree. In the preferred direction the signals in the dendritic tips coincided, allowing summation, whereas in the null direction the local signal preceded the global signal, preventing summation. Sine-wave grating stimuli produced the greatest amount of DS, especially at high velocities and low spatial frequencies. The sine-wave DS responses could be accounted for by a simple mathematical model, which summed phase-shifted signals from soma and dendritic tip. By testing different artificial morphologies, we discovered DS was relatively independent of the morphological details, but depended on having a sufficient number of inputs at the distal tips and a limited electrotonic isolation. Adding voltage-gated calcium channels to the model showed that their

  20. Velocity effect on aptamer-based circulating tumor cell isolation in microfluidic devices.

    Science.gov (United States)

    Wan, Yuan; Tan, Jifu; Asghar, Waseem; Kim, Young-tae; Liu, Yaling; Iqbal, Samir M

    2011-12-01

    The isolation and detection of rare circulating tumor cells (CTCs) has been one of the focuses of intense research recently. In a microfluidic device, a number of factors can influence the enrichment capability of surface-bound probe molecules. This article analyzes the important factor of flow velocity in a microfluidic channel. The competition of surface-grafted anti-EGFR aptamers to bind the overexpressed EGFR on cell membranes against the drag force from the fluid flow is an important efficiency determining factor. The flow rate variations are applied both in experiments and in simulation models to study their effects on CTC capture efficiency. A mixture of mononuclear cells and human Glioblastoma cells is used to isolate cancer cells from the cellular flow. The results show interdependence between the adhesion probability, isolation efficiency, and flow rate. This work can help in designing flow-through lab-on-chip devices that use surface-bound probe affinities against overexpressed biomarkers for cell isolation. This work demonstrates that microfluidic based approaches have strong potential applications in CTC detection and isolation. © 2011 American Chemical Society

  1. Spin and tunneling dynamics in an asymmetrical double quantum dot with spin-orbit coupling: Selective spin transport device

    Science.gov (United States)

    Singh, Madhav K.; Jha, Pradeep K.; Bhattacherjee, Aranya B.

    2017-09-01

    In this article, we study the spin and tunneling dynamics as a function of magnetic field in a one-dimensional GaAs double quantum dot with both the Dresselhaus and Rashba spin-orbit coupling. In particular, we consider different spatial widths for the spin-up and spin-down electronic states. We find that the spin dynamics is a superposition of slow as well as fast Rabi oscillations. It is found that the Rashba interaction strength as well as the external magnetic field strongly modifies the slow Rabi oscillations which is particularly useful for implementing solid state selective spin transport device.

  2. Single HeLa and MCF-7 cell measurement using minimized impedance spectroscopy and microfluidic device

    Science.gov (United States)

    Wang, Min-Haw; Kao, Min-Feng; Jang, Ling-Sheng

    2011-06-01

    This study presents an impedance measurement system for single-cell capture and measurement. The microwell structure which utilizes nDEP force is used to single-cell capture and a minimized impedance spectroscopy which includes a power supply chip, an impedance measurement chip and a USB microcontroller chip is used to single-cell impedance measurement. To improve the measurement accuracy of the proposed system, Biquadratic fitting is used in this study. The measurement accuracy and reliability of the proposed system are compared to those of a conventional precision impedance analyzer. Moreover, a stable material, latex beads, is used to study the impedance measurement using the minimized impedance spectroscopy with cell-trapping device. Finally, the proposed system is used to measure the impedance of HeLa cells and MCF-7 cells. The impedance of single HeLa cells decreased from 9.55 × 103 to 3.36 × 103 Ω and the impedance of single MCF-7 cells decreased from 3.48 × 103 to 1.45 × 103 Ω at an operate voltage of 0.5 V when the excitation frequency was increased from 11 to 101 kHz. The results demonstrate that the proposed impedance measurement system successfully distinguishes HeLa cells and MCF-7 cells.

  3. Electro-Deformation of Fused Cells in a Microfluidic Array Device

    Directory of Open Access Journals (Sweden)

    Yan Liu

    2016-11-01

    Full Text Available We present a new method of analyzing the deformability of fused cells in a microfluidic array device. Electrical stresses—generated by applying voltages (4–20 V across discrete co-planar microelectrodes along the side walls of a microfluidic channel—have been used to electro-deform fused and unfused stem cells. Under an electro-deformation force induced by applying an alternating current (AC signal, we observed significant electro-deformation phenomena. The experimental results show that the fused stem cells were stiffer than the unfused stem cells at a relatively low voltage (<16 V. However, at a relatively high voltage, the fused stem cells were more easily deformed than were the unfused stem cells. In addition, the electro-deformation process is modeled based on the Maxwell stress tensor and structural mechanics of cells. The theoretical results show that a positive correlation is found between the deformation of the cell and the applied voltage, which is consistent with the experimental results. Combined with a numerical analysis and experimental study, the results showed that the significant difference of the deformation ratio of the fused and unfused cells is not due to their size difference. This demonstrates that some other properties of cell membranes (such as the membrane structure were also changed in the electrofusion process, in addition to the size modification of that process.

  4. Minimally invasive and targeted therapeutic cell delivery to the skin using microneedle devices.

    Science.gov (United States)

    Gualeni, B; Coulman, S A; Shah, D; Eng, P F; Ashraf, H; Vescovo, P; Blayney, G J; Piveteau, L-D; Guy, O J; Birchall, J C

    2018-03-01

    Translation of cell therapies to the clinic is accompanied by numerous challenges, including controlled and targeted delivery of the cells to their site of action, without compromising cell viability and functionality. To explore the use of hollow microneedle devices (to date only used for the delivery of drugs and vaccines into the skin and for the extraction of biological fluids) to deliver cells into skin in a minimally invasive, user-friendly and targeted fashion. Melanocyte, keratinocyte and mixed epidermal cell suspensions were passed through various types of microneedles and subsequently delivered into the skin. Cell viability and functionality are maintained after injection through hollow microneedles with a bore size ≥ 75 μm. Healthy cells are delivered into the skin at clinically relevant depths. Hollow microneedles provide an innovative and minimally invasive method for delivering functional cells into the skin. Microneedle cell delivery represents a potential new treatment option for cell therapy approaches including skin repigmentation, wound repair, scar and burn remodelling, immune therapies and cancer vaccines. © 2017 British Association of Dermatologists.

  5. Design of user interfaces for selective editing of digital photos on touchscreen devices

    Science.gov (United States)

    Binder, Thomas; Steiding, Meikel; Wille, Manuel; Kokemohr, Nils

    2013-03-01

    When editing images it is often desirable to apply a filter with a spatially varying strength. With the usual selection tools like gradient, lasso, brush, or quick selection tools, creating masks containing such spatially varying strength values is time-consuming and cumbersome. We present an interactive filtering approach which allows to process photos selectively without the intermediate step of creating a mask containing strength values. In using this approach, the user only needs to place reference points (called control points) on the image and to adjust the spatial influence and filter strength for each control point. The filter is then applied selectively to the image, with strength values interpolated for each pixel between control points. The interpolation is based on a mixture of distances in space, luminance, and color; it is therefore a low-level operation. Since the main goal of the approach is to make selective image editing intuitive, easy, and playful, emphasis is put on the user interface: We describe the process of developing an existing mouse-driven user interface into a touch-driven one. Many question needed to be answered anew, such as how to present a slider widget on a touchscreen. Several variants are discussed and compared.

  6. Incorporation of wavelength selective devices into waveguides with applications to a miniature spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Stallard, B. R.; Kaushik, S.; Hadley, G. R.; Fritz, I. J.; Howard, A. J.; Vawter, G. A.; Wendt, J. R.; Corless, R

    1996-02-01

    This report pertains to a Laboratory Directed Research and Development project which was funded for FY94 and FY95. The goal was to develop building blocks for small, cheap sensors that use optical spectroscopy as a means of detecting chemical analytes. Such sensors can have an impact on a wide variety of technologies, such as: industrial process control, environmental monitors, chemical analysis in medicine, and automotive monitors. We describe work in fabricating and demonstrating a waveguide/grating device that can serve as the wavelength dispersive component in a miniature spectrometer. Also, we describe the invention and modeling of a new way to construct an array of optical interference filters using sub-wavelength lithography to tune the index of refraction of a fixed Fabry-Perot cavity. Next we describe progress in more efficiently calculating the fields in grating devices. Finally we present the invention of a new type of near field optical probe, applicable to scanning microscopy or optical data storage, which is based on a circular grating constructed in a waveguide. This result diverges from the original goal of the project but is quite significant in that it promises to increase the data storage capacity of CD-ROMs by 10 times.

  7. College grade point average as a personnel selection device: ethnic group differences and potential adverse impact.

    Science.gov (United States)

    Roth, P L; Bobko, P

    2000-06-01

    College grade point average (GPA) is often used in a variety of ways in personnel selection. Unfortunately, there is little empirical research literature in human resource management that informs researchers or practitioners about the magnitude of ethnic group differences and any potential adverse impact implications when using cumulative GPA for selection. Data from a medium-sized university in the Southeast (N = 7,498) indicate that the standardized average Black-White difference for cumulative GPA in the senior year is d = 0.78. The authors also conducted analyses at 3 GPA screens (3.00, 3.25, and 3.50) to demonstrate that employers (or educators) might face adverse impact at all 3 levels if GPA continues to be implemented as part of a selection system. Implications and future research are discussed.

  8. Kelvin Probe Measurements on Solar Cells and Other Thin Film Devices

    Science.gov (United States)

    Delk, John; Dils, D. W.; Lush, G. B.; Mackey, Willie R. (Technical Monitor)

    2001-01-01

    The Kelvin Probe (KP) has been used for years to measure the surface potential of metals and semiconductors. The KP is an elegantly simple but powerful tool invented by Lord Kelvin around the turn of the century. Using changes in surface potentials as a result of changing the intensity and wavelength of illumination, the KP returns data on material parameters such as band gap energies and the energy levels of interface states. We have employed the KP in the study of CdTe-based solar cells and quantum dot-based solar cells, as well as other thin-film devices. We hope eventually that the KP will be used as an in-line testing station for a fabrication process so that unfinished devices that will not meet requirements can be thrown out before the processing is completed, thus saving resources. Results of these studies will be presented.

  9. A novel cell-containing device for regenerative medicine: biodegradable nonwoven filters with peripheral blood cells promote wound healing.

    Science.gov (United States)

    Iwamoto, Ushio; Hori, Hideo; Takami, Yoshihiro; Tokushima, Yasuo; Shinzato, Masanori; Yasutake, Mikitomo; Kitaguchi, Nobuya

    2015-12-01

    The efficacy of skin regeneration devices consisting of nonwoven filters and peripheral blood cells was investigated for wound healing. We previously found that human peripheral blood cells enhanced their production of growth factors, such as transforming growth factor β1 (TGF-β1) and vascular endothelial growth factor, when they were captured on nonwoven filters. Cells on biodegradable filters were expected to serve as a local supply of growth factors and cell sources when they were placed in wounded skin. Nonwoven filters made of biodegradable polylactic acid (PLA) were cut out as 13-mm disks and placed into cell-capturing devices. Mouse peripheral blood was filtered, resulting in PLA filters with mouse peripheral blood cells (m-PBCs) at capture rates of 65.8 ± 5.2%. Then, the filters were attached to full-thickness surgical wounds in a diabetic db/db mouse skin for 14 days as a model of severe chronic wounds. The wound area treated with PLA nonwoven filters with m-PBCs (PLA/B+) was reduced to 8.5 ± 12.2% when compared with day 0, although the non-treated control wounds showed reduction only to 60.6 ± 27.8%. However, the PLA filters without m-PBCs increased the wound area to 162.9 ± 118.7%. By histopathological study, the PLA/B+ groups more effectively accelerated formation of epithelium. The m-PBCs captured on the PLA filters enhanced keratinocyte growth factor (FGF-7) and TGF-β1 productions in vitro, which may be related to wound healing. This device is useful for regeneration of wounded skin and may be adaptable for another application.

  10. Few-Layer WSe2Schottky Junction-Based Photovoltaic Devices through Site-Selective Dual Doping.

    Science.gov (United States)

    Ko, Seungpil; Na, Junhong; Moon, Young-Sun; Zschieschang, Ute; Acharya, Rachana; Klauk, Hagen; Kim, Gyu-Tae; Burghard, Marko; Kern, Klaus

    2017-12-13

    Ultrathin sheets of two-dimensional (2D) materials like transition metal dichalcogenides have attracted strong attention as components of high-performance light-harvesting devices. Here, we report the implementation of Schottky junction-based photovoltaic devices through site-selective surface doping of few-layer WSe 2 in lateral contact configuration. Specifically, whereas the drain region is covered by a strong molecular p-type dopant (NDP-9) to achieve an Ohmic contact, the source region is coated with an Al 2 O 3 layer, which causes local n-type doping and correspondingly an increase of the Schottky barrier at the contact. By scanning photocurrent microscopy using green laser light, it could be confirmed that photocurent generation is restricted to the region around the source contact. The local photoinduced charge separation is associated with a photoresponsivity of up to 20 mA W -1 and an external quantum efficiency of up to 1.3%. The demonstrated device concept should be easily transferrable to other van der Waals 2D materials.

  11. Concomitant differentiation of a population of mouse embryonic stem cells into neuron-like cells and Schwann cell-like cells in a slow-flow microfluidic device

    Science.gov (United States)

    Ramamurthy, Poornapriya; White, Joshua B.; Park, Joong Yull; Hume, Richard I.; Ebisu, Fumi; Mendez, Flor; Takayama, Shuichi; Barald, Kate F

    2016-01-01

    Background To send meaningful information to the brain, an inner ear cochlear implant (CI) must become closely coupled to as large and healthy a population of remaining Spiral Ganglion Neurons (SGN) as possible. Inner ear gangliogenesis depends on macrophage migration inhibitory factor (MIF), a directionally attractant neurotrophic cytokine made by both Schwann and supporting cells (Bank et al., 2012). MIF-induced mouse embryonic stem cell (mESC)-derived “neurons” could potentially substitute for lost or damaged SGN. mESC-derived “Schwann cells” produce MIF as do all Schwann cells (Huang et al., 2002; Roth et al., 2007, 2008) and could attract SGN to “ cell coated” implant. Results Neuron- and Schwann cell-like cells were produced from a common population of mESC in an ultra-slow flow microfluidic device. As the populations interacted; “neurons” grew over the “Schwann cell” lawn and early events in myelination were documented. Blocking MIF on the Schwann cell side greatly reduced directional neurite outgrowth. MIF-expressing “Schwann cells” were used to “coat” a CI: mouse SGN and MIF-induced “neurons” grew directionally to the CI and to a wild type but not MIF-knock out Organ of Corti explant. Conclusions Two novel stem cell-based approaches for treating the problem of sensorineural hearing loss are described. PMID:27761977

  12. Influence of Biphasic Stimulation on Olfactory Ensheathing Cells for Neuroprosthetic Devices.

    Science.gov (United States)

    Hassarati, Rachelle T; Foster, L John R; Green, Rylie A

    2016-01-01

    The recent success of olfactory ensheathing cell (OEC) assisted regeneration of injured spinal cord has seen a rising interest in the use of these cells in tissue-engineered systems. Previously shown to support neural cell growth through glial scar tissue, OECs have the potential to assist neural network formation in living electrode systems to produce superior neuroprosthetic electrode surfaces. The following study sought to understand the influence of biphasic electrical stimulation (ES), inherent to bionic devices, on cell survival and function, with respect to conventional metallic and developmental conductive hydrogel (CH) coated electrodes. The CH utilized in this study was a biosynthetic hydrogel consisting of methacrylated poly(vinyl-alcohol) (PVA), heparin and gelatin through which poly(3,4-ethylenedioxythiophene) (PEDOT) was electropolymerised. OECs cultured on Pt and CH surfaces were subjected to biphasic ES. Image-based cytometry yielded little significant difference between the viability and cell cycle of OECs cultured on the stimulated and passive samples. The significantly lower voltages measured across the CH electrodes (147 ± 3 mV) compared to the Pt (317 ± 5 mV), had shown to influence a higher percentage of viable cells on CH (91-93%) compared to Pt (78-81%). To determine the functionality of these cells following electrical stimulation, OECs co-cultured with PC12 cells were found to support neural cell differentiation (an indirect measure of neurotrophic factor production) following ES.

  13. Influence of Biphasic Stimulation on Olfactory Ensheathing Cells for Neuroprosthetic Devices

    Directory of Open Access Journals (Sweden)

    Rachelle Therese Hassarati

    2016-10-01

    Full Text Available The recent success of olfactory ensheathing cell (OEC assisted regeneration of injured spinal cord has seen a rising interest in the use of these cells in tissue-engineered systems. Previously shown to support neural cell growth through glial scar tissue, OECs have the potential to assist neural network formation in living electrode systems to produce superior neuroprosthetic electrode surfaces. The following study sought to understand the influence of biphasic electrical stimulation (ES, inherent to bionic devices, on cell survival and function, with respect to conventional metallic and developmental conductive hydrogel (CH coated electrodes. The CH utilised in this study was a biosynthetic hydrogel consisting of methacrylated poly(vinyl-alcohol (PVA, heparin and gelatin through which poly(3,4-ethylenedioxythiophene (PEDOT was electropolymerised. OECs cultured on Pt and CH surfaces were subjected to biphasic ES. Image-based cytometry yielded little significant difference between the viability and cell cycle of OECs cultured on the stimulated and passive samples. The significantly lower voltages measured across the CH electrodes (147 ± 3 mV compared to the Pt (317 ± 5 mV, had shown to influence a higher percentage of viable cells on CH (91 - 93 % compared to Pt (78 - 81 %. To determine the functionality of these cells following electrical stimulation, OECs co-cultured with PC12 cells were found to support neural cell differentiation (an indirect measure of neurotrophic factor production following ES.

  14. Aberration-free FTIR spectroscopic imaging of live cells in microfluidic devices.

    Science.gov (United States)

    Chan, K L Andrew; Kazarian, Sergei G

    2013-07-21

    The label-free, non-destructive chemical analysis offered by FTIR spectroscopic imaging is a very attractive and potentially powerful tool for studies of live biological cells. FTIR imaging of live cells is a challenging task, due to the fact that cells are cultured in an aqueous environment. While the synchrotron facility has proven to be a valuable tool for FTIR microspectroscopic studies of single live cells, we have demonstrated that high quality infrared spectra of single live cells using an ordinary Globar source can also be obtained by adding a pair of lenses to a common transmission liquid cell. The lenses, when placed on the transmission cell window, form pseudo hemispheres which removes the refraction of light and hence improve the imaging and spectral quality of the obtained data. This study demonstrates that infrared spectra of single live cells can be obtained without the focus shifting effect at different wavenumbers, caused by the chromatic aberration. Spectra of the single cells have confirmed that the measured spectral region remains in focus across the whole range, while spectra of the single cells measured without the lenses have shown some erroneous features as a result of the shift of focus. It has also been demonstrated that the addition of lenses can be applied to the imaging of cells in microfabricated devices. We have shown that it was not possible to obtain a focused image of an isolated cell in a droplet of DPBS in oil unless the lenses are applied. The use of the approach described herein allows for well focused images of single cells in DPBS droplets to be obtained.

  15. Stem cell culture and differentiation in microfluidic devices toward organ-on-a-chip.

    Science.gov (United States)

    Zhang, Jie; Wei, Xiaofeng; Zeng, Rui; Xu, Feng; Li, XiuJun

    2017-06-01

    Microfluidic lab-on-a-chip provides a new platform with unique advantages to mimic complex physiological microenvironments in vivo and has been increasingly exploited to stem cell research. In this review, we highlight recent advances of microfluidic devices for stem cell culture and differentiation toward the development of organ-on-a-chip, especially with an emphasis on vital innovations within the last 2 years. Various aspects for improving on-chip stem-cell culture and differentiation, particularly toward organ-on-a-chip, are discussed, along with microenvironment control, surface modification, extracellular scaffolds, high throughput and stimuli. The combination of microfluidic technologies and stem cells hold great potential toward versatile systems of 'organ-on-a-chip' as desired. Adapted with permission from [1-8].

  16. ZnO nanotube-based dye-sensitized solar cell and its application in self-powered devices

    KAUST Repository

    Han, Jingbin

    2010-09-10

    Abstract High-density vertically aligned ZnO nanotube arrays were fabricated on FTO substrates by a simple and facile chemical etching process from electrodeposited ZnO nanorods. The nanotube formation was rationalized in terms of selective dissolution of the (001) polar face. The morphology of the nanotubes can be readily controlled by electrodeposition parameters for the nanorod precursor. By employing the 5.1 μm-length nanotubes as the photoanode for a dye-sensitized solar cell (DSSC), a full-sun conversion efficiency of 1.18% was achieved. Furthermore, we show that the DSSC unit can serve as a robust power source to drive a humidity sensor, with a potential for self-powered devices. © 2010 IOP Publishing Ltd.

  17. A Membrane-Free Neutral pH Formate Fuel Cell Enabled by a Selective Nickel Sulfide Oxygen Reduction Catalyst.

    Science.gov (United States)

    Yan, Bing; Concannon, Nolan M; Milshtein, Jarrod D; Brushett, Fikile R; Surendranath, Yogesh

    2017-06-19

    Polymer electrolyte membranes employed in contemporary fuel cells severely limit device design and restrict catalyst choice, but are essential for preventing short-circuiting reactions at unselective anode and cathode catalysts. Herein, we report that nickel sulfide Ni 3 S 2 is a highly selective catalyst for the oxygen reduction reaction in the presence of 1.0 m formate. We combine this selective cathode with a carbon-supported palladium (Pd/C) anode to establish a membrane-free, room-temperature formate fuel cell that operates under benign neutral pH conditions. Proof-of-concept cells display open circuit voltages of approximately 0.7 V and peak power values greater than 1 mW cm -2 , significantly outperforming the identical device employing an unselective platinum (Pt) cathode. The work establishes the power of selective catalysis to enable versatile membrane-free fuel cells. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. B cell activating factor (BAFF) selects IL-10-B cells over IL-10+B cells during inflammatory responses.

    Science.gov (United States)

    Ma, Ning; Zhang, Yu; Liu, Qilin; Wang, Zhiding; Liu, Xiaoling; Zhu, Gaizhi; Yu, Dandan; Han, Gencheng; Chen, Guojiang; Hou, Chunmei; Wang, Tianxiao; Ma, Yuanfang; Shen, Beifen; Li, Yan; Xiao, He; Wang, Renxi

    2017-05-01

    B cell activating factor (BAFF) regulates B cell maturation, survival, function, and plays a critical pathogenic role in autoimmune diseases. It remains unclear how BAFF affects IL-10 - B cells versus regulatory B cells (Bregs) in inflammatory responses. In this study, we found that IL-10-expressing Bregs decreased in lupus-prone MRL/lpr mice and experimental allergic encephalomyelitis (EAE) mice. On blockade of the effects of BAFF with TACI-IgG, IL-10 + Bregs were upregulated in MRL/lpr and EAE mice. In addition, BAFF expanded IL-10 + B cells over IL-10 - B cells under noninflammatory conditions in vitro, whereas it expanded IL-10 - B cells over IL-10 + B cells during inflammatory responses, such as stimulation with autoantigen and LPS. Finally, the selection of IL-10 - B cells over IL-10 + B cells by BAFF was dependent on BAFF receptors (BAFFR, TACI, and BCMA) that were upregulated by inflammatory responses. This study suggests that BAFF selects IL-10 - B cells over IL-10 + regulatory B cells via BAFF receptors in inflammatory responses. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Quantitative control of mitochondria transfer between live single cells using a microfluidic device

    Directory of Open Access Journals (Sweden)

    Ken-Ichi Wada

    2017-12-01

    Full Text Available Quantitative control of mitochondria transfer between live cells is a promising approach for genetic manipulation of mitochondrial DNA (mtDNA because single mitochondrion transfer to a mtDNA-less (ρ0 cell potentially leads to homoplasmy of mtDNA. In this paper, we describe a method for quantitative control of mitochondria transfer between live single cells. For this purpose, we fabricated novel microfluidic devices having cell paring structures with a 4.1, 5.6 or 10.0 μm-length microtunnel. When cells were fused through a microtunnel using the Sendai virus envelope-based method, a strictured cytoplasmic connection was achieved with a length corresponding to that of the microtunnel. Elongation of the cytoplasmic connection led to a decrease in mitochondria transfer to the fusion partner. Moreover, some cell pairs that fused through a 10.0 μm-length microtunnel showed single mitochondrion transfer. Fused cells were spontaneously disconnected from each other when they were recovered in a normal culture medium. These results suggest that our cell fusion method can perform quantitative control of mitochondria transfer that includes a single mitochondrion transfer.

  20. Alantolactone selectively ablates acute myeloid leukemia stem and progenitor cells

    Directory of Open Access Journals (Sweden)

    Yahui Ding

    2016-09-01

    Full Text Available Abstract Background The poor outcomes for patients diagnosed with acute myeloid leukemia (AML are largely attributed to leukemia stem cells (LSCs which are difficult to eliminate with conventional therapy and responsible for relapse. Thus, new therapeutic strategies which could selectively target LSCs in clinical leukemia treatment and avoid drug resistance are urgently needed. However, only a few small molecules have been reported to show anti-LSCs activity. Methods The aim of the present study was to identify alantolactone as novel agent that can ablate acute myeloid leukemia stem and progenitor cells from AML patient specimens and evaluate the anticancer activity of alantolactone in vitro and in vivo. Results The present study is the first to demonstrate that alantolactone, a prominent eudesmane-type sesquiterpene lactone, could specifically ablate LSCs from AML patient specimens. Furthermore, in comparison to the conventional chemotherapy drug, cytosine arabinoside (Ara-C, alantolactone showed superior effects of leukemia cytotoxicity while sparing normal hematopoietic cells. Alantolactone induced apoptosis with a dose-dependent manner by suppression of NF-kB and its downstream target proteins. DMA-alantolactone, a water-soluble prodrug of alantolactone, could suppress tumor growth in vivo. Conclusions Based on these results, we propose that alantolactone may represent a novel LSCs-targeted therapy and eudesmane-type sesquiterpene lactones offer a new scaffold for drug discovery towards anti-LSCs agents.

  1. Right or left? Side selection for a totally implantable vascular access device: a randomised observational study.

    Science.gov (United States)

    Lin, Wen-Ying; Lin, Chih-Peng; Hsu, Chih-Hung; Lee, Ying-Hui; Lin, Yi-Ting; Hsu, Meng-Chi; Shao, Yu-Yun

    2017-09-26

    Totally implantable vascular access device (TIVAD)-related complications interfere in the anticancer treatment and increase medical expenses. We examined whether the implantation side of central line TIVADs is associated with the occurrence of thrombotic or occlusion events. We enrolled patients with cancer who required central line TIVADs and randomised them to receive the TIVAD implantation on either the left or right side. The primary endpoint was the occurrence of catheter-related thrombotic or occlusion events. We randomised 240 patients, of which 235 received TIVAD implantation according to the protocol. In the per-protocol cohort, 117 and 118 patients received implantation on the left and right sides, respectively. Catheter-related thrombotic or occlusion events occurred in 9 (4%) patients, accounting for 0.065 events per 1000 catheter-days. Between the patients with left- and right-sided implantations, the occurrence rates (P=0.333) and the time from catheter implantation to the occurrence of thrombotic or occlusion events (P=0.328) were both similar. In the multivariate analysis, the side of implantation remained unassociated with the occurrence of thrombotic or occlusion events. The side of central line TIVAD implantation was not associated with the occurrence of catheter-related thrombotic or occlusion events in patients with cancer.

  2. Evaluation of mitochondrial membrane potential using a computerized device with a tetraphenylphosphonium-selective electrode

    Czech Academy of Sciences Publication Activity Database

    Labajová, A.; Vojtíšková, Alena; Křiváková, P.; Kofránek, J.; Drahota, Zdeněk; Houštěk, Josef

    2006-01-01

    Roč. 353, č. 1 (2006), s. 37-42 ISSN 0003-2697 R&D Projects: GA ČR(CZ) GD303/03/H065; GA ČR(CZ) GA303/06/1261 Grant - others:GA UK(CZ) 126/04/C; IGA MŠk(CZ) RP 394 Institutional research plan: CEZ:AV0Z50110509 Keywords : membrane potential * TPP -selective electrode Subject RIV: CE - Biochemistry Impact factor: 2.948, year: 2006

  3. Ventricular assist device support as a bridge to heart transplantation in patients with giant cell myocarditis.

    Science.gov (United States)

    Murray, Lindsay K; González-Costello, Jose; Jonas, Samual N; Sims, Daniel B; Morrison, Kerry A; Colombo, Paolo C; Mancini, Donna M; Restaino, Susan W; Joye, Evan; Horn, Evelyn; Takayama, Hiroo; Marboe, Charles C; Naka, Yoshifumi; Jorde, Ulrich P; Uriel, Nir

    2012-03-01

    Giant cell myocarditis (GCM) carries a poor prognosis and many patients require end-stage therapies. This study sought to determine the outcome of patients bridged with ventricular assist devices (VAD) to orthotopic heart transplantation (OHT). A retrospective data collection of all patients with GCM was performed. Diagnosis was determined by endomyocardial or explanted heart biopsy. Eight patients were found, but two of those patients went directly to OHT and were excluded. The remaining six patients received VADs, and these patients, aged 44 ± 18 years, were included. Five of the six patients were bridged with biventricular support and one patient was supported by left ventricular assist device (LVAD) alone. Two patients died on device support. Four patients were bridged to OHT 77 ± 42 days after device implantation. All four patients bridged with a VAD are alive, with a mean follow-up of 5.7 ± 4.1 years. Two patients were found to have recurrent GCM in the transplanted heart and were treated successfully with immunosuppression. Three patients had high grade (2R) rejection at 66 ± 52 days post-OHT. Cardiac function was preserved in all patients, and only one patient had cardiac allograft vasculopathy. Patients with end-stage GCM can be successfully bridged with VADs to OHT with very good post-OHT survival. The proper immunosuppressive regimen for this group needs further investigation given the frequency of rejection and GCM recurrence.

  4. Fabrication of cyclo olefin polymer microfluidic devices for trapping and culturing of yeast cells.

    Science.gov (United States)

    Puza, Sevde; Gencturk, Elif; Odabasi, Irem E; Iseri, Emre; Mutlu, Senol; Ulgen, Kutlu O

    2017-06-01

    A microfluidic platform is designed and fabricated to investigate the role of uncharacterized YOR060C (Sld7) protein in aging in yeast cells for the first time. Saccharomyces cerevisiae yeast cells are trapped in the series of C-shaped regions (0.5 nL) of COP (cyclo olefin polymer), PMMA (poly methylmethacrylate), or PS (polystyrene) microbioreactors. The devices are fabricated using hot embossing and thermo-compression bonding methods. Photolithography and electrochemical etching are used to form the steel mold needed for hot embossing. The cell cycle processes are investigated by monitoring green fluorescent protein (GFP) tagged Sld7 expressions under normal as well as calorie restricted conditions. The cells are loaded at 1 μL/min flowrate and trapped successfully within each chamber. The medium is continuously fed at 0.1 μL/min throughout the experiments. Fluorescent signals of the low abundant Sld7 proteins could be distinguished only on COP devices. The background fluorescence of COP is found 1.22 and 7.24 times lower than that of PMMA, and PS, respectively. Hence, experiments are continued with COP, and lasted for more than 40 h without any contamination. The doubling time of the yeast cells are found as 72 min and 150 min, and the growth rates as 9.63 × 10 -3  min -1 and 4.62 × 10 -3  min -1 , in 2% glucose containing YPD and YNB medium, respectively. The product concentration (Sld7p:GFP) increased in accordance with cell growth. The dual role of Sld7 protein in both cell cycle and chronological aging needs to be further investigated following the preliminary experimental results.

  5. Microfluidic devices for stem-cell cultivation, differentiation and toxicity testing

    Science.gov (United States)

    Becker, Holger; Hansen-Hagge, Thomas; Kurtz, Andreas; Mrowka, Ralf; Wölfl, Stefan; Gärtner, Claudia

    2017-02-01

    The development of new drugs is time-consuming, extremely expensive and often promising drug candidates fail in late stages of the development process due to the lack of suitable tools to either predict toxicological effects or to test drug candidates in physiologically relevant environments prior to clinical tests. We therefore try to develop diagnostic multiorgan microfluidic chips based on patient specific induced pluripotent stem cell (iPS) technology to explore liver dependent toxic effects of drugs on individual human tissues such as liver or kidney cells. Based initially on standardized microfluidic modules for cell culture, we have developed integrated microfluidic devices which contain different chambers for cell/tissue cultivation. The devices are manufactured using injection molding of thermoplastic polymers such as polystyrene or cyclo-olefin polymer. In the project, suitable surface modification methods of the used materials had to be explored. We have been able to successfully demonstrate the seeding, cultivation and further differentiation of modified iPS, as shown by the use of differentiation markers, thus providing a suitable platform for toxicity testing and potential tissue-tissue interactions.

  6. Interplay between efficiency and device architecture for small molecule organic solar cells.

    Science.gov (United States)

    Williams, Graeme; Sutty, Sibi; Aziz, Hany

    2014-06-21

    Small molecule organic solar cells (OSCs) have experienced a resurgence of interest over their polymer solar cell counterparts, owing to their improved batch-to-batch (thus, cell-to-cell) reliability. In this systematic study on OSC device architecture, we investigate five different small molecule OSC structures, including the simple planar heterojunction (PHJ) and bulk heterojunction (BHJ), as well as several planar-mixed structures. The different OSC structures are studied over a wide range of donor:acceptor mixing concentrations to gain a comprehensive understanding of their charge transport behavior. Transient photocurrent decay measurements provide crucial information regarding the interplay between charge sweep-out and charge recombination, and ultimately hint toward space charge effects in planar-mixed structures. Results show that the BHJ/acceptor architecture, comprising a BHJ layer with high C60 acceptor content, generates OSCs with the highest performance by balancing charge generation with charge collection. The performance of other device architectures is largely limited by hole transport, with associated hole accumulation and space charge effects.

  7. Separation of red blood cells in deep deterministic lateral displacement devices

    Science.gov (United States)

    Kabacaoglu, Gokberk; Biros, George

    2017-11-01

    Microfluidic cell separation techniques are of great interest since they help rapid medical diagnoses and tests. Deterministic lateral displacement (DLD) is one of them. A DLD device consists of arrays of pillars. Main flow and alignment of the pillars define two different directions. Size-based separation of rigid spherical particles is possible as they follow one of these directions depending on their sizes. However, the separation of non-spherical deformable particles such as red blood cells (RBCs) is more complicated than that due to their intricate dynamics. We study the separation of RBCs in DLD using an in-house integral equation solver. We systematically investigate the effects of the interior fluid viscosity and the membrane elasticity of an RBC on its behavior. These mechanical properties of a cell determine its deformability, which can be altered by several diseases. We particularly consider deep devices in which an RBC can show rich dynamics such as tank-treading and tumbling. It turns out that strong hydrodynamic lift force moves the tank-treading cells along the pillars and downward force leads the tumbling ones to move with the flow. Thereby, deformability-based separation of RBCs is possible.

  8. Application of the Sensor Selection Approach in Polymer Electrolyte Membrane Fuel Cell Prognostics and Health Management

    Directory of Open Access Journals (Sweden)

    Lei Mao

    2017-09-01

    Full Text Available In this paper, the sensor selection approach is investigated with the aim of using fewer sensors to provide reliable fuel cell diagnostic and prognostic results. The sensitivity of sensors is firstly calculated with a developed fuel cell model. With sensor sensitivities to different fuel cell failure modes, the available sensors can be ranked. A sensor selection algorithm is used in the analysis, which considers both sensor sensitivity to fuel cell performance and resistance to noise. The performance of the selected sensors in polymer electrolyte membrane (PEM fuel cell prognostics is also evaluated with an adaptive neuro-fuzzy inference system (ANFIS, and results show that the fuel cell voltage can be predicted with good quality using the selected sensors. Furthermore, a fuel cell test is performed to investigate the effectiveness of selected sensors in fuel cell fault diagnosis. From the results, different fuel cell states can be distinguished with good quality using the selected sensors.

  9. Processing and modeling issues for thin-film solar cell devices. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Birkmire, R.W.; Phillips, J.E. [Univ. of Delaware, Newark, DE (United States). Institute of Energy Conversion

    1997-11-01

    During the third phase of the subcontract, IEC researchers have continued to provide the thin film PV community with greater depth of understanding and insight into a wide variety of issues including: the deposition and characterization of CuIn{sub 1-x}Ga{sub x}Se{sub 2}, a-Si, CdTe, CdS, and TCO thin films; the relationships between film and device properties; and the processing and analysis of thin film PV devices. This has been achieved through the systematic investigation of all aspects of film and device production and through the analysis and quantification of the reaction chemistries involved in thin film deposition. This methodology has led to controlled fabrications of 15% efficient CuIn{sub 1-x}Ga{sub x}Se{sub 2} solar cells over a wide range of Ga compositions, improved process control of the fabrication of 10% efficient a-Si solar cells, and reliable and generally applicable procedures for both contacting and doping films. Additional accomplishments are listed below.

  10. Effect of Mesostructured Layer upon Crystalline Properties and Device Performance on Perovskite Solar Cells.

    Science.gov (United States)

    Listorti, Andrea; Juarez-Perez, Emilio J; Frontera, Carlos; Roiati, Vittoria; Garcia-Andrade, Laura; Colella, Silvia; Rizzo, Aurora; Ortiz, Pablo; Mora-Sero, Ivan

    2015-05-07

    One of the most fascinating characteristics of perovskite solar cells (PSCs) is the retrieved obtainment of outstanding photovoltaic (PV) performances withstanding important device configuration variations. Here we have analyzed CH3NH3PbI3-xClx in planar or in mesostructured (MS) configurations, employing both titania and alumina scaffolds, fully infiltrated with perovskite material or presenting an overstanding layer. The use of the MS scaffold induces to the perovskite different structural properties, in terms of grain size, preferential orientation, and unit cell volume, in comparison to the ones of the material grown with no constraints, as we have found out by X-ray diffraction analyses. We have studied the effect of the PSC configuration on photoinduced absorption and time-resolved photoluminescence, complementary techniques that allow studying charge photogeneration and recombination. We have estimated electron diffusion length in the considered configurations observing a decrease when the material is confined in the MS scaffold with respect to a planar architecture. However, the presence of perovskite overlayer allows an overall recovering of long diffusion lengths explaining the record PV performances obtained with a device configuration bearing both the mesostructure and a perovskite overlayer. Our results suggest that performance in devices with perovskite overlayer is mainly ruled by the overlayer, whereas the mesoporous layer influences the contact properties.

  11. β-escin selectively targets the glioblastoma-initiating cell population and reduces cell viability.

    Science.gov (United States)

    Harford-Wright, Elizabeth; Bidère, Nicolas; Gavard, Julie

    2016-10-11

    Glioblastoma multiforme (GBM) is a highly aggressive tumour of the central nervous system and is associated with an extremely poor prognosis. Within GBM exists a subpopulation of cells, glioblastoma-initiating cells (GIC), which possess the characteristics of progenitor cells, have the ability to initiate tumour growth and resist to current treatment strategies. We aimed at identifying novel specific inhibitors of GIC expansion through use of a large-scale chemical screen of approved small molecules. Here, we report the identification of the natural compound β-escin as a selective inhibitor of GIC viability. Indeed, β-escin was significantly cytotoxic in nine patient-derived GIC, whilst exhibiting no substantial effect on the other human cancer or control cell lines tested. In addition, β-escin was more effective at reducing GIC growth than current clinically used cytotoxic agents. We further show that β-escin triggers caspase-dependent cell death combined with a loss of stemness properties. However, blocking apoptosis could not rescue the β-escin-induced reduction in sphere formation or stemness marker activity, indicating that β-escin directly modifies the stem identity of GIC, independent of the induction of cell death. Thus, this study has repositioned β-escin as a promising potential candidate to selectively target the aggressive population of initiating cells within GBM.

  12. Holographic optical tweezers combined with a microfluidic device for exposing cells to fast environmental changes

    Science.gov (United States)

    Eriksson, Emma; Scrimgeour, Jan; Enger, Jonas; Goksör, Mattias

    2007-05-01

    Optical manipulation techniques have become an important research tool for single cell experiments in microbiology. Using optical tweezers, single cells can be trapped and held during long experiments without risk of cross contamination or compromising viability. However, it is often desirable to not only control the position of a cell, but also to control its environment. We have developed a method that combines optical tweezers with a microfluidic device. The microfluidic system is fabricated by soft lithography in which a constant flow is established by a syringe pump. In the microfluidic system multiple laminar flows of different media are combined into a single channel, where the fluid streams couple viscously. Adjacent media will mix only by diffusion, and consequently two different environments will be separated by a mixing region a few tens of micrometers wide. Thus, by moving optically trapped cells from one medium to another we are able to change the local environment of the cells in a fraction of a second. The time needed to establish a change in environment depends on several factors such as the strength of the optical traps and the steepness of the concentration gradient in the mixing region. By introducing dynamic holographic optical tweezers several cells can be trapped and analyzed simultaneously, thus shortening data acquisition time. The power of this system is demonstrated on yeast (Saccharomyces cerevisiae) subjected to osmotic stress, where the volume of the yeast cell and the spatial localization of green fluorescent proteins (GFP) are monitored using fluorescence microscopy.

  13. Mkit: A cell migration assay based on microfluidic device and smartphone.

    Science.gov (United States)

    Yang, Ke; Wu, Jiandong; Peretz-Soroka, Hagit; Zhu, Ling; Li, Zhigang; Sang, Yaoshuo; Hipolito, Jolly; Zhang, Michael; Santos, Susy; Hillier, Craig; de Faria, Ricardo Lobato; Liu, Yong; Lin, Francis

    2018-01-15

    Mobile sensing based on the integration of microfluidic device and smartphone, so-called MS 2 technology, has enabled many applications over recent years, and continues to stimulate growing interest in both research communities and industries. In particular, it has been envisioned that MS 2 technology can be developed for various cell functional assays to enable basic research and clinical applications. Toward this direction, in this paper, we describe the development of a MS 2 -based cell functional assay for testing cell migration (the M kit ). The system is constructed as an integrated test kit, which includes microfluidic chips, a smartphone-based imaging platform, the phone apps for image capturing and data analysis, and a set of reagent and accessories for performing the cell migration assay. We demonstrated that the M kit can effectively measure purified neutrophil and cancer cell chemotaxis. Furthermore, neutrophil chemotaxis can be tested from a drop of whole blood using the M kit with red blood cell (RBC) lysis. The effects of chemoattractant dose and gradient profile on neutrophil chemotaxis were also tested using the M kit . In addition to research applications, we demonstrated the effective use of the M kit for on-site test at the hospital and for testing clinical samples from chronic obstructive pulmonary disease patient. Thus, this developed M kit provides an easy and integrated experimental platform for cell migration related research and potential medical diagnostic applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. High-Efficiency Multiscale Modeling of Cell Deformations in Confined Microenvironments in Microcirculation and Microfluidic Devices

    Science.gov (United States)

    Lu, Huijie; Peng, Zhangli

    2017-11-01

    Our goal is to develop a high-efficiency multiscale modeling method to predict the stress and deformation of cells during the interactions with their microenvironments in microcirculation and microfluidic devices, including red blood cells (RBCs) and circulating tumor cells (CTCs). There are more than 1 billion people in the world suffering from RBC diseases, e.g. anemia, sickle cell diseases, and malaria. The mechanical properties of RBCs are changed in these diseases due to molecular structure alternations, which is not only important for understanding the disease pathology but also provides an opportunity for diagnostics. On the other hand, the mechanical properties of cancer cells are also altered compared to healthy cells. This can lead to acquired ability to cross the narrow capillary networks and endothelial gaps, which is crucial for metastasis, the leading cause of cancer mortality. Therefore, it is important to predict the deformation and stress of RBCs and CTCs in microcirculations. We are developing a high-efficiency multiscale model of cell-fluid interaction to study these two topics.

  15. Symmetric synaptic patterns between starburst amacrine cells and direction selective ganglion cells in the rabbit retina.

    Science.gov (United States)

    Chen, Yung-Cheng; Chiao, Chuan-Chin

    2008-05-01

    Inputs from starburst amacrine cells (SACs) to ON-OFF direction selective ganglion cells (DSGCs) in the rabbit retina are themselves directional. However, the synaptic asymmetry between SACs and DSGCs required for generating direction selectivity has been controversial. We investigated dendritic contacts and distribution of inhibitory synapses between SACs and their overlapped DSGCs. Double injection of SAC/DSGC pairs and quantitative analysis revealed no obvious asymmetry of dendritic contacts between SACs and DSGCs. Furthermore, examination of the inhibitory input pattern on the dendrites of DSGCs using antibodies against GABA(A) receptors also suggested an isotropic arrangement with the overlapping SACs in both the preferred and the null directions. Therefore, the presynaptic mechanism of direction selectivity upon DSGCs may not result from a simple asymmetric arrangement with overlapping SACs. Multiple layer interactions and sophisticated synaptic connections between SACs and DSGCs are necessary. (c) 2008 Wiley-Liss, Inc.

  16. Microfluidic device for DNA amplification of single cancer cells isolated from whole blood by self-seeding microwells

    NARCIS (Netherlands)

    Yang, Yoon Sun; Rho, Hoon Suk; Stevens, Michiel; Tibbe, Arjan G.J.; Gardeniers, Johannes G.E.; Terstappen, Leonardus Wendelinus Mathias Marie

    2015-01-01

    Self-seeding microwell chips can sort single cells into 6400 wells based on cell size and their identity verified by immunofluorescence staining. Here, we developed a microfluidic device in which these single cells can be placed, lysed and their DNA amplified for further interrogation. Whole blood

  17. High-throughput deterministic single-cell encapsulation and droplet pairing, fusion, and shrinkage in a single microfluidic device

    NARCIS (Netherlands)

    Schoeman, R.M.; Kemna, Evelien; Wolbers, F.; van den Berg, Albert

    In this article, we present a microfluidic device capable of successive high-yield single-cell encapsulation in droplets, with additional droplet pairing, fusion, and shrinkage. Deterministic single-cell encapsulation is realized using Dean-coupled inertial ordering of cells in a Yin-Yang-shaped

  18. Gene transfer and protein dynamics in stem cells using single cell electroporation in a microfluidic device

    NARCIS (Netherlands)

    Valero, Ana; Post, Janine Nicole; van Nieuwkasteele, Jan William; ter Braak, Paulus Martinus; Kruijer, W.; van den Berg, Albert

    There is great interest in genetic modification of bone marrow-derived mesenchymal stem cells (MSC), not only for research purposes but also for use in (autologous) patient-derived-patient-used transplantations. A major drawback of bulk methods for genetic modifications of (stem) cells, like

  19. Characteristics of isotope-selective chemical reactor with gas-separating device

    International Nuclear Information System (INIS)

    Gorshunov, N.M.; Kalitin, S.A.; Laguntsov, N.I.; Neshchimenko, Yu.P.; Sulaberidze, G.A.

    1988-01-01

    A study was made on characteristics of separating stage, composed of isotope-selective chemical (or photochemical) reactor and membrane separating cascade (MSC), designated for separation of isotope-enriched products from lean reagents. MSC represents the counterflow cascade for separation of two-component mixtures. Calculations show that for the process of carton isotope separation the electric power expences for MSC operation are equal to 20 kWxh/g of CO 2 final product at 13 C isotope content in it equal to 75%. Application of the membrane gas-separating cascade at rather small electric power expenses enables to perform cascading of isotope separation in the course of nonequilibrium chemical reactions

  20. A versatile microfluidic device for high throughput production of microparticles and cell microencapsulation.

    Science.gov (United States)

    Akbari, Samin; Pirbodaghi, Tohid; Kamm, Roger D; Hammond, Paula T

    2017-06-13

    Biocompatible microparticles are valuable tools in biomedical research for applications such as drug delivery, cell transplantation therapy, and analytical assays. However, their translation into clinical research and the pharmaceutical industry has been slow due to the lack of techniques that can produce microparticles with controlled physicochemical properties at high throughput. We introduce a robust microfluidic platform for the production of relatively homogeneous microdroplets at a generation frequency of up to 3.1 MHz, which is about three orders of magnitude higher than the production rate of a conventional microfluidic drop maker. We demonstrated the successful implementation of our device for production of biocompatible microparticles with various crosslinking mechanisms and cell microencapsulation with high cell viability.

  1. Device characterization for design optimization of 4 junction inverted metamorphic concentrator solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Geisz, John F.; France, Ryan M.; Steiner, Myles A.; Friedman, Daniel J. [National Renewable Energy Laboratory, Golden, CO 80401 (United States); García, Iván [National Renewable Energy Laboratory, Golden, CO 80401 USA and Instituto de Energía Solar, Universidad Politécnica de Madrid, Avda Complutense s/n, 28040 Madrid (Spain)

    2014-09-26

    Quantitative electroluminescence (EL) and luminescent coupling (LC) analysis, along with more conventional characterization techniques, are combined to completely characterize the subcell JV curves within a fourjunction (4J) inverted metamorphic solar cell (IMM). The 4J performance under arbitrary spectral conditions can be predicted from these subcell JV curves. The internal radiative efficiency (IRE) of each junction has been determined as a function of current density from the external radiative efficiency using optical modeling, but this required the accurate determination of the individual junction current densities during the EL measurement as affected by LC. These measurement and analysis techniques can be applied to any multijunction solar cell. The 4J IMM solar cell used to illustrate these techniques showed excellent junction quality as exhibited by high IRE and a one-sun AM1.5D efficiency of 36.3%. This device operates up to 1000 suns without limitations due to any of the three tunnel junctions.

  2. Device for equalizing molten electrolyte content in a fuel cell stack

    Science.gov (United States)

    Smith, J.L.

    1985-12-23

    A device for equalizing the molten electrolyte content throughout the height of a fuel cell stack is disclosed. The device includes a passageway for electrolyte return with electrolyte wettable wicking material in the opposite end portions of the passageway. One end portion is disposed near the upper, negative end of the stack where electrolyte flooding occurs. The second end portion is placed near the lower, positive end of the stack where electrolyte is depleted. Heating means are provided at the upper portion of the passageway to increase electrolyte vapor pressure in the upper wicking material. The vapor is condensed in the lower passageway portion and conducted as molten electrolyte in the lower wick to the positive end face of the stack. An inlet is provided to inject a modifying gas into the passageway and thereby control the rate of electrolyte return.

  3. Organic light-emitting devices integrated with solar cells: High contrast and energy recycling

    Science.gov (United States)

    Yang, Chih-Jen; Cho, Ting-Yi; Lin, Chun-Liang; Wu, Chung-Chih

    2007-04-01

    In this letter, the authors report that by integrating organic light-emitting devices (OLEDs) with solar cells, luminous ambient-light reflection as low as 1.4% (even superior to that achieved with polarizers) can be achieved without compromising the electroluminescence efficiency for high-contrast display applications. Furthermore, in such a configuration, the photon energies of the incident ambient light and the portion of OLED emission not getting outside of the device can be recycled into useful electrical power via the photovoltaic action, instead of being totally wasted as in other reported contrast-enhancement techniques. These features, the authors believe, shall make this technique attractive for high-contrast display applications and portable/mobile electronics that are highly power aware.

  4. Optically induced dielectropheresis sorting with automated medium exchange in an integrated optofluidic device resulting in higher cell viability.

    Science.gov (United States)

    Lee, Gwo-Bin; Wu, Huan-Chun; Yang, Po-Fu; Mai, John D

    2014-08-07

    We demonstrated the integration of a microfluidic device with an optically induced dielectrophoresis (ODEP) device such that the critical medium replacement process was performed automatically and the cells could be subsequently manipulated by using digitally projected optical images. ODEP has been demonstrated to generate sufficient forces for manipulating particles/cells by projecting a light pattern onto photoconductive materials which creates virtual electrodes. The production of the ODEP force usually requires a medium that has a suitable electrical conductivity and an appropriate dielectric constant. Therefore, a 0.2 M sucrose solution is commonly used. However, this requires a complicated medium replacement process before one is able to manipulate cells. Furthermore, the 0.2 M sucrose solution is not suitable for the long-term viability of cells. In comparison to conventional manual processes, our automated medium replacement process only took 25 minutes. Experimental data showed that there was up to a 96.2% recovery rate for the manipulated cells. More importantly, the survival rate of the cells was greatly enhanced due to this faster automated process. This newly developed microfluidic chip provided a promising platform for the rapid replacement of the cell medium and this was also the first time that an ODEP device was integrated with other active flow control components in a microfluidic device. By improving cell viability after cell manipulation, this design may contribute to the practical integration of ODEP modules into other lab-on-a-chip devices and biomedical applications in the future.

  5. Photovoltaic device

    Energy Technology Data Exchange (ETDEWEB)

    Reese, Jason A.; Keenihan, James R.; Gaston, Ryan S.; Kauffmann, Keith L.; Langmaid, Joseph A.; Lopez, Leonardo C.; Maak, Kevin D.; Mills, Michael E.; Ramesh, Narayan; Teli, Samar R.

    2015-09-01

    The present invention is premised upon an improved photovoltaic device ("PV device"), more particularly to an improved photovoltaic device (10) with a multilayered photovoltaic cell assembly (100) and a body portion (200) joined at an interface region (410) and including an intermediate layer (500), at least one interconnecting structural member (1500), relieving feature (2500), unique component geometry, or any combination thereof.

  6. Photovoltaic device

    Energy Technology Data Exchange (ETDEWEB)

    Reese, Jason A; Keenihan, James R; Gaston, Ryan S; Kauffmann, Keith L; Langmaid, Joseph A; Lopez, Leonardo; Maak, Kevin D; Mills, Michael E; Ramesh, Narayan; Teli, Samar R

    2017-03-21

    The present invention is premised upon an improved photovoltaic device ("PV device"), more particularly to an improved photovoltaic device with a multilayered photovoltaic cell assembly and a body portion joined at an interface region and including an intermediate layer, at least one interconnecting structural member, relieving feature, unique component geometry, or any combination thereof.

  7. Functional characterization of circulating tumor cells with a prostate-cancer-specific microfluidic device.

    Directory of Open Access Journals (Sweden)

    Brian J Kirby

    Full Text Available Cancer metastasis accounts for the majority of cancer-related deaths owing to poor response to anticancer therapies. Molecular understanding of metastasis-associated drug resistance remains elusive due to the scarcity of available tumor tissue. Isolation of circulating tumor cells (CTCs from the peripheral blood of patients has emerged as a valid alternative source of tumor tissue that can be subjected to molecular characterization. However, issues with low purity and sensitivity have impeded adoption to clinical practice. Here we report a novel method to capture and molecularly characterize CTCs isolated from castrate-resistant prostate cancer patients (CRPC receiving taxane chemotherapy. We have developed a geometrically enhanced differential immunocapture (GEDI microfluidic device that combines an anti-prostate specific membrane antigen (PSMA antibody with a 3D geometry that captures CTCs while minimizing nonspecific leukocyte adhesion. Enumeration of GEDI-captured CTCs (defined as intact, nucleated PSMA+/CD45- cells revealed a median of 54 cells per ml identified in CRPC patients versus 3 in healthy donors. Direct comparison with the commercially available CellSearch® revealed a 2-400 fold higher sensitivity achieved with the GEDI device. Confocal microscopy of patient-derived GEDI-captured CTCs identified the TMPRSS2:ERG fusion protein, while sequencing identified specific androgen receptor point mutation (T868A in blood samples spiked with only 50 PC C4-2 cells. On-chip treatment of patient-derived CTCs with docetaxel and paclitaxel allowed monitoring of drug-target engagement by means of microtubule bundling. CTCs isolated from docetaxel-resistant CRPC patients did not show any evidence of drug activity. These measurements constitute the first functional assays of drug-target engagement in living circulating tumor cells and therefore have the potential to enable longitudinal monitoring of target response and inform the development of new

  8. A key role of starburst amacrine cells in originating retinal directional selectivity and optokinetic eye movement.

    Science.gov (United States)

    Yoshida, K; Watanabe, D; Ishikane, H; Tachibana, M; Pastan, I; Nakanishi, S

    2001-06-01

    The directional selectivity of retinal ganglion cell responses represents a primitive pattern recognition that operates within a retinal neural circuit. The cellular origin and mechanism of directional selectivity were investigated by selectively eliminating retinal starburst amacrine cells, using immunotoxin-mediated cell targeting techniques. Starburst cell ablation in the adult retina abolished not only directional selectivity of ganglion cell responses but also an optokinetic eye reflex derived by stimulus movement. Starburst cells therefore serve as the key element that discriminates the direction of stimulus movement through integrative synaptic transmission and play a pivotal role in information processing that stabilizes image motion.

  9. Automatic illumination compensation device based on a photoelectrochemical biofuel cell driven by visible light

    Science.gov (United States)

    Yu, You; Han, Yanchao; Xu, Miao; Zhang, Lingling; Dong, Shaojun

    2016-04-01

    Inverted illumination compensation is important in energy-saving projects, artificial photosynthesis and some forms of agriculture, such as hydroponics. However, only a few illumination adjustments based on self-powered biodetectors that quantitatively detect the intensity of visible light have been reported. We constructed an automatic illumination compensation device based on a photoelectrochemical biofuel cell (PBFC) driven by visible light. The PBFC consisted of a glucose dehydrogenase modified bioanode and a p-type semiconductor cuprous oxide photocathode. The PBFC had a high power output of 161.4 μW cm-2 and an open circuit potential that responded rapidly to visible light. It adjusted the amount of illumination inversely irrespective of how the external illumination was changed. This rational design of utilizing PBFCs provides new insights into automatic light adjustable devices and may be of benefit to intelligent applications.Inverted illumination compensation is important in energy-saving projects, artificial photosynthesis and some forms of agriculture, such as hydroponics. However, only a few illumination adjustments based on self-powered biodetectors that quantitatively detect the intensity of visible light have been reported. We constructed an automatic illumination compensation device based on a photoelectrochemical biofuel cell (PBFC) driven by visible light. The PBFC consisted of a glucose dehydrogenase modified bioanode and a p-type semiconductor cuprous oxide photocathode. The PBFC had a high power output of 161.4 μW cm-2 and an open circuit potential that responded rapidly to visible light. It adjusted the amount of illumination inversely irrespective of how the external illumination was changed. This rational design of utilizing PBFCs provides new insights into automatic light adjustable devices and may be of benefit to intelligent applications. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr00759g

  10. Current Constriction at Electrode/Electrolyte Interfaces in Solid Oxide Cell Electrochemical Devices Calculated Via 3D Reconstructions

    DEFF Research Database (Denmark)

    Nielsen, Jimmi; Jørgensen, Peter Stanley; Graves, Christopher R.

    2016-01-01

    Electrochemical devices such as batteries, fuel cells, electrolysers, electrochemical reactors and electrochemical sensors are important technologies for the present and the future society. For further improvement or maturing of the various technologies it is important to understand, characterize...

  11. 4β-Hydroxywithanolide E selectively induces oxidative DNA damage for selective killing of oral cancer cells.

    Science.gov (United States)

    Tang, Jen-Yang; Huang, Hurng-Wern; Wang, Hui-Ru; Chan, Ya-Ching; Haung, Jo-Wen; Shu, Chih-Wen; Wu, Yang-Chang; Chang, Hsueh-Wei

    2018-03-01

    Reactive oxygen species (ROS) induction had been previously reported in 4β-hydroxywithanolide (4βHWE)-induced selective killing of oral cancer cells, but the mechanism involving ROS and the DNA damage effect remain unclear. This study explores the role of ROS and oxidative DNA damage of 4βHWE in the selective killing of oral cancer cells. Changes in cell viability, morphology, ROS, DNA double strand break (DSB) signaling (γH2AX foci in immunofluorescence and DSB signaling in western blotting), and oxidative DNA damage (8-oxo-2'deoxyguanosine [8-oxodG]) were detected in 4βHWE-treated oral cancer (Ca9-22) and/or normal (HGF-1) cells. 4βHWE decreased cell viability, changed cell morphology and induced ROS generation in oral cancer cells rather than oral normal cells, which were recovered by a free radical scavenger N-acetylcysteine (NAC). For immunofluorescence, 4βHWE also accumulated more of the DSB marker, γH2AX foci, in oral cancer cells than in oral normal cells. For western blotting, DSB signaling proteins such as γH2AX and MRN complex (MRE11, RAD50, and NBS1) were overexpressed in 4βHWE-treated oral cancer cells in different concentrations and treatment time. In the formamidopyrimidine-DNA glycolyase (Fpg)-based comet assay and 8-oxodG-based flow cytometry, the 8-oxodG expressions were higher in 4βHWE-treated oral cancer cells than in oral normal cells. All the 4βHWE-induced DSB and oxidative DNA damage to oral cancer cells were recovered by NAC pretreatment. Taken together, the 4βHWE selectively induced DSB and oxidative DNA damage for the ROS-mediated selective killing of oral cancer cells. © 2017 Wiley Periodicals, Inc.

  12. Study of ions - molecules reactions in the gas phase with collision reaction cell devices: Applications to the direct resolution of spectroscopic interferences in ICP-MS

    International Nuclear Information System (INIS)

    Favre, G.

    2008-12-01

    Inductively Coupled Plasma Mass Spectrometry emerged as the most widespread mass spectrometry technique in inorganic analytical chemistry for determining the concentration of a given isotope or an isotope ratio. The problem of spectroscopic interferences, inherent to this technique, finds a solution through the use of reaction cell devices. An in situ interference removal is feasible with the addition of a well selected gas in the cell. The understanding of the chemistry of ions-molecules interactions in the gas phase is however fundamental to optimize the efficiency of such devices. An accurate knowledge of experimental conditions in the reaction zone according to instrumental parameters appears crucial in order to interpret observed reactivities. This preliminary study is then used for the resolution of two nuclear field characteristic interferences. (author)

  13. All polymer photovoltaics: From small inverted devices to large roll-to-roll coated and printed solar cells

    DEFF Research Database (Denmark)

    Liu, Yao; Larsen-Olsen, Thue Trofod; Zhao, Xingang

    2013-01-01

    Inverted all polymer solar cells based on a blend of a perylene diimide based polymer acceptor and a dithienosilole based polymer donor were fabricated from small area devices to roll-to-roll (R2R) coated and printed large area modules. The device performance was successfully optimized by using...... solution processibility and R2R coated and printed large area (4.2 cm 2) solar cells exhibited a PCE of 0.20%. © 2013 Elsevier B.V....

  14. Process and device for the selective excitation and separation of isotopes

    International Nuclear Information System (INIS)

    Ducas, T.W.

    1976-01-01

    Description is given of a method for selectively populating high-lying excited states of atoms or molecules. It comprises: excitation of atoms or molecules with a first circularly polarized pulsed radiation, the coherent frequency components of first pulsed radiation have frequencies corresponding to the energy difference between a lower energy level and the frequency split levels of an intermediate energy level, the duration of pulse being less than 2π/Δω, where Δω is the frequency difference of the split levels; applying a second circularly polarized pulsed radiation to atoms or molecules for a time subsequent to the termination of first radiation, the coherent frequency components of second pulsed radiation have frequencies corresponding to the energy difference between the split levels of intermediate energy level and an upper energy level, the duration of second pulse being less than 2π/Δω. The first and second radiation have the same handedness of circular polarization, whereby upper energy level has a greater population than prior to excitation by first and second radiation pulses [fr

  15. Measurements of Ion Selective Containment on the RF Charge Breeder Device BRIC

    CERN Document Server

    Variale, Vincenzo; Batazova, Marina; Boggia, Antonio; Clauser, Tarcisio; Kuznetsov, Gennady I; Rainò, Antonio; Shiyankov, Sergey; Skarbo, Boris A; Valentino, Vincenzo; Verrone, Grazia

    2005-01-01

    The "charge state breeder" BRIC (BReeding Ion Charge) is based on an EBIS source and it is designed to accept Radioactive Ion Beam (RIB) with charge +1, in a slow injection mode, to increase their charge state up to +n. BRIC has been developed at the INFN section of Bari (Italy) during these last 3 years with very limited funds. Now, it has been assembled at the LNL (Italy) where are in progress the first tests as stand alone source. The new feature of BRIC, with respect to the classical EBIS, is given by the insertion, in the ion drift chamber, of a Radio Frequency (RF) Quadrupole aiming to filtering the unwanted elements and then making a more efficient containment of the wanted ions. In this contribution, the measurements of the selective effect on the ion charge state containement of the RF quadrupole field, applied on the ion chamber, will be reported and discussed. The ion charge state analisys of the ions trapped in BRIC seem confirm, as foreseen by simulation results carried out previously, that the s...

  16. Selection method and device for reactor core performance calculation input indication

    International Nuclear Information System (INIS)

    Yuto, Yoshihiro.

    1994-01-01

    The position of a reactor core component on a reactor core map, which is previously designated and optionally changeable, is displayed by different colors on a CRT screen by using data of a data file incorporating results of a calculation for reactor core performance, such as incore thermal limit values. That is, an operator specifies the kind of the incore component to be sampled on a menu screen, to display the position of the incore component which satisfies a predetermined condition on the CRT screen by different colors in the form of a reactor core map. The position for the reactor core component displayed on the CRT screen by different colors is selected and designated on the screen by a touch panel, a mouse or a light pen, thereby automatically outputting detailed data of evaluation for the reactor core performance of the reactor core component at the indicated position. Retrieval of coordinates of fuel assemblies to be data sampled and input of the coordinates and demand for data sampling can be conducted at once by one menu screen. (N.H.)

  17. Digital Devices, Distraction and Student Performance - Does Cell Phone Use Reduce Learning?

    Science.gov (United States)

    Duncan, Douglas K.; Hoekstra, A. R.; Wilcox, B. R.

    2012-01-01

    The recent increase in the use of digital devices such as laptop computers, iPads and web-enabled cell phones has generated concern about how technologies affect student performance. Combining observation, survey, and interview data, this research assesses the effects of technology use for student attitudes and learning. Data were gathered in eight introductory science courses at one large public university in 2010-2011. Results show a significant negative correlation between in-class cell phone use and overall course grades, corresponding to a drop of 0.36 ± 0.08 on a 4-point scale where 4.0 = A. These findings are consistent with recent research[1] suggesting students cannot multi-task nearly as effectively as they think they can. While 75% of students reported regular cell phone use, observation data suggests undergraduates typically under-report the frequency of in-class digital device use. [1] Ophir, E., Nass, C. and A.D. Wagner. 2009. "Cognitive Control in Media Multi-Taskers.” Proceedings of the National Academy of Sciences, 106: 15583-15587.

  18. Review on the degradation and device physics of quantum dot solar cells

    Science.gov (United States)

    Afshar, Elham N.; Rouhi, Rasoul; Gorji, Nima E.

    2015-12-01

    Briefly, we reviewed the latest progress in energy conversion efficiency and degradation rate of the quantum dot (QD) solar cells. QDs are zero dimension nanoparticles with tunable size and accordingly tunable band gap. The maximum performance of the most advanced QD solar cells was reported to be around 10%. Nevertheless, majority of research groups do not investigate the stability of such devices. QDs are cheaper replacements for silicon or other thin film materials with a great potential to significantly increase the photon conversion efficiency via two ways: (i) creating multiple excitons by absorbing a single hot photon, and (ii) formation of intermediate bands (IBs) in the band gap of the background semiconductor that enables the absorption of low energy photons (two-step absorption of sub-band gap photons). Apart from low conversion efficiency, QD solar cells also suffer from instability under real operation and stress conditions. Strain, dislocations and variation in size of the dots (under pressure of the other layers) are the main degradation resources. While some new materials (i.e. perovskites) showed an acceptable high performance, the QD devices are still inefficient with an almost medium rate of 4% (2010) to 10% (2015).

  19. Numerical study on the complete blood cell sorting using particle tracing and dielectrophoresis in a microfluidic device

    Science.gov (United States)

    Ali, Haider; Park, Cheol Woo

    2016-11-01

    In this study, a numerical model of a microfluidic device with particle tracing and dielectrophoresis field-flow fractionation was employed to perform a complete and continuous blood cell sorting. A low voltage was applied to electrodes to separate the red blood cells, white blood cells, and platelets based on their cell size. Blood cell sorting and counting were performed by evaluating the cell trajectories, displacements, residence times, and recovery rates in the device. A novel numerical technique was used to count the number of separated blood cells by estimating the displacement and residence time of the cells in a microfluidic device. For successful blood cell sorting, the value of cells displacement must be approximately equal to or higher than the corresponding maximum streamwise distance. The study also proposed different outlet designs to improve blood cell separation. The basic outlet design resulted in a higher cells recovery rate than the other outlets design. The recovery rate decreased as the number of inlet cells and flow rates increased because of the high particle-particle interactions and collisions with walls. The particle-particle interactions significantly affect blood cell sorting and must therefore be considered in future work.

  20. Proteomic Selection of Immunodiagnostic Antigens for Human African Trypanosomiasis and Generation of a Prototype Lateral Flow Immunodiagnostic Device

    Science.gov (United States)

    Sullivan, Lauren; Wall, Steven J.; Carrington, Mark; Ferguson, Michael A. J.

    2013-01-01

    Background The diagnosis of Human African Trypanosomiasis relies mainly on the Card Agglutination Test for Trypanosomiasis (CATT). While this test is successful, it is acknowledged that there may be room for improvement. Our aim was to develop a prototype lateral flow test based on the detection of antibodies to trypanosome antigens. Methodology/Principal Findings We took a non-biased approach to identify potential immunodiagnostic parasite protein antigens. The IgG fractions from the sera from Trypanosoma brucei gambiense infected and control patients were isolated using protein-G affinity chromatography and then immobilized on Sepharose beads. The IgG-beads were incubated with detergent lysates of trypanosomes and those proteins that bound were identified by mass spectrometry-based proteomic methods. This approach provided a list of twenty-four trypanosome proteins that selectively bound to the infection IgG fraction and that might, therefore, be considered as immunodiagnostic antigens. We selected four antigens from this list (ISG64, ISG65, ISG75 and GRESAG4) and performed protein expression trials in E. coli with twelve constructs. Seven soluble recombinant protein products (three for ISG64, two for ISG65 and one each for ISG75 and GRESAG4) were obtained and assessed for their immunodiagnostic potential by ELISA using individual and/or pooled patient sera. The ISG65 and ISG64 construct ELISAs performed well with respect to detecting T. b. gambiense infections, though less well for detecting T. b. rhodesiense infections, and the best performing ISG65 construct was used to develop a prototype lateral flow diagnostic device. Conclusions/Significance Using a panel of eighty randomized T. b. gambiense infection and control sera, the prototype showed reasonable sensitivity (88%) and specificity (93%) using visual readout in detecting T. b. gambiense infections. These results provide encouragement to further develop and optimize the lateral flow device for clinical

  1. Proteomic selection of immunodiagnostic antigens for human African trypanosomiasis and generation of a prototype lateral flow immunodiagnostic device.

    Directory of Open Access Journals (Sweden)

    Lauren Sullivan

    Full Text Available The diagnosis of Human African Trypanosomiasis relies mainly on the Card Agglutination Test for Trypanosomiasis (CATT. While this test is successful, it is acknowledged that there may be room for improvement. Our aim was to develop a prototype lateral flow test based on the detection of antibodies to trypanosome antigens.We took a non-biased approach to identify potential immunodiagnostic parasite protein antigens. The IgG fractions from the sera from Trypanosoma brucei gambiense infected and control patients were isolated using protein-G affinity chromatography and then immobilized on Sepharose beads. The IgG-beads were incubated with detergent lysates of trypanosomes and those proteins that bound were identified by mass spectrometry-based proteomic methods. This approach provided a list of twenty-four trypanosome proteins that selectively bound to the infection IgG fraction and that might, therefore, be considered as immunodiagnostic antigens. We selected four antigens from this list (ISG64, ISG65, ISG75 and GRESAG4 and performed protein expression trials in E. coli with twelve constructs. Seven soluble recombinant protein products (three for ISG64, two for ISG65 and one each for ISG75 and GRESAG4 were obtained and assessed for their immunodiagnostic potential by ELISA using individual and/or pooled patient sera. The ISG65 and ISG64 construct ELISAs performed well with respect to detecting T. b. gambiense infections, though less well for detecting T. b. rhodesiense infections, and the best performing ISG65 construct was used to develop a prototype lateral flow diagnostic device.Using a panel of eighty randomized T. b. gambiense infection and control sera, the prototype showed reasonable sensitivity (88% and specificity (93% using visual readout in detecting T. b. gambiense infections. These results provide encouragement to further develop and optimize the lateral flow device for clinical use.

  2. Efficient Regular Perovskite Solar Cells Based on Pristine [70]Fullerene as Electron-Selective Contact.

    Science.gov (United States)

    Collavini, Silvia; Kosta, Ivet; Völker, Sebastian F; Cabanero, German; Grande, Hans J; Tena-Zaera, Ramón; Delgado, Juan Luis

    2016-06-08

    [70]Fullerene is presented as an efficient alternative electron-selective contact (ESC) for regular-architecture perovskite solar cells (PSCs). A smart and simple, well-described solution processing protocol for the preparation of [70]- and [60]fullerene-based solar cells, namely the fullerene saturation approach (FSA), allowed us to obtain similar power conversion efficiencies for both fullerene materials (i.e., 10.4 and 11.4 % for [70]- and [60]fullerene-based devices, respectively). Importantly, despite the low electron mobility and significant visible-light absorption of [70]fullerene, the presented protocol allows the employment of [70]fullerene as an efficient ESC. The [70]fullerene film thickness and its solubility in the perovskite processing solutions are crucial parameters, which can be controlled by the use of this simple solution processing protocol. The damage to the [70]fullerene film through dissolution during the perovskite deposition is avoided through the saturation of the perovskite processing solution with [70]fullerene. Additionally, this fullerene-saturation strategy improves the performance of the perovskite film significantly and enhances the power conversion efficiency of solar cells based on different ESCs (i.e., [60]fullerene, [70]fullerene, and TiO2 ). Therefore, this universal solution processing protocol widens the opportunities for the further development of PSCs. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. A comprehensive device modelling of perovskite solar cell with inorganic copper iodide as hole transport material

    Science.gov (United States)

    Zulqarnain Haider, Syed; Anwar, Hafeez; Wang, Mingqing

    2018-03-01

    Hole transport material (HTM) plays an important role in the efficiency and stability of perovskite solar cells (PSCs). Spiro-MeOTAD, the commonly used HTM, is costly and can be easily degraded by heat and moisture, thus offering hindrance to commercialize PSCs. There is dire need to find an alternate inorganic and stable HTM to exploit PSCs with their maximum capability. In this paper, a comprehensive device simulation is used to study various possible parameters that can influence the performance of perovskite solar cell with CuI as HTM. These include the effect of doping density, defect density and thickness of absorber layer, along with the influence of diffusion length of carriers as well as electron affinity of electron transport layer (ETM) and HTM on the performance of PSCs. In addition, hole mobility and doping density of HTM is also investigated. CuI is a p-type inorganic material with low cost and relatively high stability. It is found that concentration of dopant in absorber layer and HTM, the electron affinity of HTM and ETM affect the performance of solar cell minutely, while cell performance improves greatly with the reduction of defect density. Upon optimization of parameters, power conversion efficiency for this device is found to be 21.32%. The result shows that lead-based PSC with CuI as HTM is an efficient system. Enhancing the stability and reduction of defect density are critical factors for future research. These factors can be improved by better fabrication process and proper encapsulation of solar cell.

  4. All-in-polymer injection molded device for single cell capture using multilevel silicon master fabrication

    DEFF Research Database (Denmark)

    Tanzi, S.; Larsen, S.T.; Matteucci, M.

    2012-01-01

    This work demonstrates a novel all-in-polymer device for single cell capture applicable for biological recordings. The chip is injection molded and comprises a "cornered" (non planar) aperture. It has been demonstrated how cornered apertures are straightforward to mold in PDMS [1,2]. In this study...... we demonstrate cornered apertures made in a thermoplastic polymer. One of the advantages of cornered apertures is the ease of microscopy under a standard inverted optical microscope, when using transparent materials. After the part is injection molded, the sealing of the chip is performed by thermal...

  5. Technical approaches to induce selective cell death of pluripotent stem cells.

    Science.gov (United States)

    Jeong, Ho-Chang; Cho, Seung-Ju; Lee, Mi-Ok; Cha, Hyuk-Jin

    2017-07-01

    Despite the recent promising results of clinical trials using human pluripotent stem cell (hPSC)-based cell therapies for age-related macular degeneration (AMD), the risk of teratoma formation resulting from residual undifferentiated hPSCs remains a serious and critical hurdle for broader clinical implementation. To mitigate the tumorigenic risk of hPSC-based cell therapy, a variety of approaches have been examined to ablate the undifferentiated hPSCs based on the unique molecular properties of hPSCs. In the present review, we offer a brief overview of recent attempts at selective elimination of undifferentiated hPSCs to decrease the risk of teratoma formation in hPSC-based cell therapy.

  6. A new device to select carriers for biomass immobilization and application in an aerobic/anaerobic fixed-bed sequencing batch biofilm reactor for nitrogen removal.

    Science.gov (United States)

    Sarti, A; Lamon, A W; Ono, A; Foresti, E

    2016-12-01

    This study proposes a new approach to selecting a biofilm carrier for immobilization using dissolved oxygen (DO) microsensors to measure the thickness of aerobic and anaerobic layers in biofilm. The biofilm carriers tested were polyurethane foam, mineral coal (MC), basaltic gravel, and low-density polyethylene. Development of layers in the biofilm carrier surface was evaluated using a flow cell device, and DO profiles were conducted to determine the size of the layers (aerobic and anaerobic). MC was the biofilm carrier selected due to allowing the development of larger aerobic and anaerobic layers in the biofilm (896 and 1,058 μm, respectively). This ability is supposed to improve simultaneous nitrogen removal by nitrification and denitrification biological processes. Thus, as a biofilm carrier, MC was used in a fixed-bed sequencing batch biofilm reactor (FB-SBBR) for treatment of wastewater with a high ammonia concentration (100-400 mgNH 4 + -N L -1 ). The FB-SBBR (15.0 L) was filled with matrices of the carrier and operated under alternating aeration and non-aeration periods of 6 h each. At a mean nitrogen loading rate of 0.55 ± 0.10 kgNH 4 + -N m -3 d -1 , the reactor attained a mean nitrification efficiency of 95 ± 9% with nitrite as the main product (aerobic period). Mean denitrification efficiency during the anoxic period was 72 ± 13%.

  7. New screening methodology for selection of polymeric materials for transdermal drug delivery devices

    Science.gov (United States)

    Falcone, Roberto P.

    As medical advances extend the human lifespan, the level of chronic illnesses will increase and thus straining the needs of the health care system that, as a result, governments will need to balance expenses without upsetting national budgets. Therefore, the selection of a precise and affordable drug delivery technology is seen as the most practical solution for governments, health care professionals, and consumers. Transdermal drug delivery patches (TDDP) are one of the best economical technologies that are favored by pharmaceutical companies and physicians alike because it offers fewer complications when compared to other delivery technologies. TDDP provides increased efficiency, safety and convenience for the patient. The TDDP segment within the US and Global drug delivery markets were valued at 5.6 and 12.7 billion respectively in 2009. TDDP is forecasted to reach $31.5 billion in 2015. The present TDDP technology involves the fabrication of a patch that consists of a drug embedded in a polymeric matrix. The diffusion coefficient is determined from the slope of the cumulative drug release versus time. It is a trial and error method that is time and labor consuming. With all the advantages that TDDPs can offer, the methodology used to achieve the so-called optimum design has resulted in several incidents where the safety and design have been put to question in recent times (e.g. Fentanyl). A more logical screening methodology is needed. This work shows the use of a modified Duda Zielinsky equation (DZE). Experimental release curves from commercial are evaluated. The experimental and theoretical Diffusion Coefficient values are found to be within the limits specified in the patent literature. One interesting finding is that the accuracy of the DZE is closer to experimental values when the type of Molecular Shape and Radius are used. This work shows that the modified DZE could be used as an excellent screening tool to determine the optimal polymeric matrices that

  8. The influence of electrical effects on device performance of organic solar cells with nano-structured electrodes

    DEFF Research Database (Denmark)

    Mirsafaei, Mina; Rubahn, Horst-Günter; Madsen, Morten

    2017-01-01

    in inorganic devices. While this light-trapping concept can be transferred to organic devices, one has to also consider nanostructure-induced electrical effects on the device performance, due to the fundamental difference in the organic semiconducting material properties compared to their inorganic......Integration of light-trapping features and exploitation of metal nanostructure plasmonic effects are promising approaches for enhancing the power conversion efficiency of organic solar cells. These approaches’ effects on the light absorption enhancement have been widely studied, especially...... counterparts. In this contribution, we exemplarily model the electrical properties of organic solar cells with rectangular-grating structures, as compared to planar reference devices. Based on our numeric results, we demonstrate that, beyond an optical absorption enhancement, the device fill factor improves...

  9. Analysis of Performance Resulting from the Design of Selected Hand-Held Input Control Devices and Visual Displays

    OpenAIRE

    Spencer, Ronald Allen

    2000-01-01

    Since the introduction of graphical user interfaces (GUI), input control devices have become an integral part of desktop computing. When interfacing with GUIs, these input control devices have become the human's primary means of communicating with the computer. Although there have been a number of experiments conducted on pointing devices for desktop machine, there is little research on pointing devices for wearable computer technology. This is surprising because pointing devices are a maj...

  10. The Architecture of Colloidal Quantum Dot Solar Cells: Materials to Devices

    KAUST Repository

    Kramer, Illan J.

    2014-01-08

    The materials chemistry of Colloidal Quantum Dot (CQDs) suspended in solution and processed into films has provided a foundation onto which useful photovoltaic devices can be built. These active materials offer the benefits of solution processing paired with the flexibility of adjustable bandgaps, tailored to suit a particular need. In parallel with these advances, pursuing device geometries that better leverage the available electronic properties of CQD films has borne fruit in further advancing CQD solar cell performance. For active materials such as CQD films where 1/α, where alpha is the absorption coefficient, is of the same order as the free carrier extraction length, external quantum efficiency (EQE) measurements have proved useful in profiling the effectiveness of each nanometer of device thickness at extracting photogenerated carriers. Because CQD films have the added complications of being made of variable-sized constituent material building blocks as well as being deposited from solution, the nature of charge transport through the films can also be size-dependent and matrix dependent.

  11. The antimicrobial peptide nisin Z induces selective toxicity and apoptotic cell death in cultured melanoma cells.

    Science.gov (United States)

    Lewies, Angélique; Wentzel, Johannes Frederik; Miller, Hayley Christy; Du Plessis, Lissinda Hester

    2018-01-01

    Reprogramming of cellular metabolism is now considered one of the hallmarks of cancer. Most malignant cells present with altered energy metabolism which is associated with elevated reactive oxygen species (ROS) generation. This is also evident for melanoma, the leading cause of skin cancer related deaths. Altered mechanisms affecting mitochondrial bioenergetics pose attractive targets for novel anticancer therapies. Antimicrobial peptides have been shown to exhibit selective anticancer activities. In this study, the anti-melanoma potential of the antimicrobial peptide, nisin Z, was evaluated in vitro. Nisin Z was shown to induce selective toxicity in melanoma cells compared to non-malignant keratinocytes. Furthermore, nisin Z was shown to negatively affect the energy metabolism (glycolysis and mitochondrial respiration) of melanoma cells, increase reactive oxygen species generation and cause apoptosis. Results also indicate that nisin Z can decrease the invasion and proliferation of melanoma cells demonstrating its potential use against metastasis associated with melanoma. As nisin Z seems to place a considerable extra burden on the energy metabolism of melanoma cells, combination therapies with known anti-melanoma agents may be effective treatment options. Copyright © 2017 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.

  12. A portable cell-based optical detection device for rapid detection of Listeria and Bacillus toxins

    Science.gov (United States)

    Banerjee, Pratik; Banada, Padmapriya P.; Rickus, Jenna L.; Morgan, Mark T.; Bhunia, Arun K.

    2005-11-01

    A mammalian cell-based optical biosensor was built to detect pathogenic Listeria and Bacillus species. This sensor measures the ability of the pathogens to infect and induce cytotoxicity on hybrid lymphocyte cell line (Ped-2E9) resulting in the release of alkaline phosphatase (ALP) that can be detected optically using a portable spectrophotometer. The Ped-2E9 cells were encapsulated in collagen gel matrices and grown in 48-well plates or in specially designed filtration tube units. Toxin preparations or bacterial cells were introduced and ALP release was assayed after 3-5 h. Pathogenic L. monocytogenes strains or the listeriolysin toxins preparation showed cytotoxicity ranging from 55% - 92%. Toxin preparations (~20 μg/ml) from B. cereus strains showed 24 - 98% cytotoxicity. In contrast, a non-pathogenic L. innocua (F4247) and a B. substilis induced only 2% and 8% cytotoxicity, respectively. This cell-based detection device demonstrates its ability to detect the presence of pathogenic Listeria and Bacillus species and can potentially be used onsite for food safety or in biosecurity application.

  13. Microfluidic dielectrophoresis device for trapping, counting and detecting Shewanella oneidensis at the cell level.

    Science.gov (United States)

    Chen, Xiangyu; Liang, Zhiting; Li, Daobo; Xiong, Ying; Xiong, Penghui; Guan, Yong; Hou, Shuangyue; Hu, Yue; Chen, Shan; Liu, Gang; Tian, Yangchao

    2018-01-15

    Shewanella oneidensis, a model organism for electrochemical activity bacteria, has been widely studied at the biofilm level. However, to obtain more information regarding this species, it is essential to develop an approach to trap and detect S. oneidensis at the cell level. In this study, we report a rapid and label-free microfluidic platform for trapping, counting and detecting S. oneidensis cells. A microfluidic chip was integrated with a modified dielectrophoresis (DEP) trapping technique and hole arrays of different hole sizes. By numerical simulation and an elaborate electric field distribution design, S. oneidensis cells were successfully trapped and positioned in the hole arrays. Real time fluorescence imaging was also used to observe the trapping process. With the aid of a homemade image program, the trapped bacteria were accurately counted, and the results demonstrated that the amount of bacteria correlated with the hole sizes. As one of the significant applications of the device, Raman identification and detection of countable S. oneidensis cells was accomplished in two kinds of holes. The microfluidic platform provides a quantitative sample preparation and analysis method at the cell level that could be widely applied in the environmental and energy fields. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. A mathematical model of breast cancer cell motion through a microfluidic device

    Science.gov (United States)

    Barber, Jared

    2017-11-01

    Deaths due to breast cancer are usually caused by metastases at other locations (e.g. bone), not by the primary tumor. Much research has targeted understanding how to lower the metastatic potential of individual breast cancer cells with the end goal being the mitigation of the effects of breast cancer on the 3.5 million people in the US affected by the disease. Experiments show that metastatic potential correlates well with the physical properties of a cell and its surrounding environment. Biology also suggests that mechanotransduction of cellular pathways (e.g. apoptosis, division) can affect metastatic potential. Because of these insights, we are developing a mechanical model of breast cancer cell translocation in microvessels. Our first model is a two-dimensional model with interconnected viscoelastic elements submersed in a surrounding Stokes flow. This model has been used to consider breast cancer cell translocation through a microfluidic device that was designed as a diagnostic tool for assessing the metastatic potential of breast cells. We will present this current model and share results. We believe that further development of this model will allow consideration of metastatic potential in both in vitro and in vivo settings.

  15. Copper-substituted perovskite compositions for solid oxide fuel cell cathodes and oxygen reduction electrodes in other electrochemical devices

    Science.gov (United States)

    Rieke, Peter C [Pasco, WA; Coffey, Gregory W [Richland, WA; Pederson, Larry R [Kennewick, WA; Marina, Olga A [Richland, WA; Hardy, John S [Richland, WA; Singh, Prabhaker [Richland, WA; Thomsen, Edwin C [Richland, WA

    2010-07-20

    The present invention provides novel compositions that find advantageous use in making electrodes for electrochemical cells. Also provided are electrochemical devices that include active oxygen reduction electrodes, such as solid oxide fuel cells, sensors, pumps and the like. The compositions comprises a copper-substituted ferrite perovskite material. The invention also provides novel methods for making and using the electrode compositions and solid oxide fuel cells and solid oxide fuel cell assemblies having cathodes comprising the compositions.

  16. Visual cells remember earlier applied target: plasticity of orientation selectivity.

    Directory of Open Access Journals (Sweden)

    Narcis Ghisovan

    Full Text Available BACKGROUND: A canonical proposition states that, in mature brain, neurons responsive to sensory stimuli are tuned to specific properties installed shortly after birth. It is amply demonstrated that that neurons in adult visual cortex of cats are orientation-selective that is they respond with the highest firing rates to preferred oriented stimuli. METHODOLOGY/PRINCIPAL FINDINGS: In anesthetized cats, prepared in a conventional fashion for single cell recordings, the present investigation shows that presenting a stimulus uninterruptedly at a non-preferred orientation for twelve minutes induces changes in orientation preference. Across all conditions orientation tuning curves were investigated using a trial by trial method. Contrary to what has been previously reported with shorter adaptation duration, twelve minutes of adaptation induces mostly attractive shifts, i.e. toward the adapter. After a recovery period allowing neurons to restore their original orientation tuning curves, we carried out a second adaptation which produced three major results: (1 more frequent attractive shifts, (2 an increase of their magnitude, and (3 an additional enhancement of responses at the new or acquired preferred orientation. Additionally, we also show that the direction of shifts depends on the duration of the adaptation: shorter adaptation in most cases produces repulsive shifts, whereas adaptation exceeding nine minutes results in attractive shifts, in the same unit. Consequently, shifts in preferred orientation depend on the duration of adaptation. CONCLUSION/SIGNIFICANCE: The supplementary response improvements indicate that neurons in area 17 keep a memory trace of the previous stimulus properties, thereby upgrading cellular performance. It also highlights the dynamic nature of basic neuronal properties in adult cortex since repeated adaptations modified both the orientation tuning selectivity and the response strength to the preferred orientation. These

  17. Influence of the starting materials on performance of high temperature oxide fuel cells devices

    Directory of Open Access Journals (Sweden)

    Emília Satoshi Miyamaru Seo

    2004-03-01

    Full Text Available High temperature solid oxide fuel cells (SOFCs offer an environmentally friendly technology to convert gaseous fuels such as hydrogen, natural gas or gasified coal into electricity at high efficiencies. Besides the efficiency, higher than those obtained from the traditional energy conversion systems, a fuel cell provides many other advantages like reliability, modularity, fuel flexibility and very low levels of NOx and SOx emissions. The high operating temperature (950-1000 °C used by the current generation of the solid oxide fuel cells imposes severe constraints on materials selection in order to improve the lifetime of the cell. Besides the good electrical, electrochemical, mechanical and thermal properties, the individual cell components must be stable under the fuel cell operating atmospheres. Each material has to perform not only in its own right but also in conjunction with other system components. For this reason, each cell component must fulfill several different criteria. This paper reviews the materials and the methods used to fabricate the different cell components, such as the cathode, the electrolyte, the anode and the interconnect. Some remarkable results, obtained at IPEN (Nuclear Energy Research Institute in São Paulo, have been presented.

  18. Using injection molding and reversible bonding for easy fabrication of magnetic cell trapping and sorting devices

    Science.gov (United States)

    Royet, David; Hériveaux, Yoann; Marchalot, Julien; Scorretti, Riccardo; Dias, André; Dempsey, Nora M.; Bonfim, Marlio; Simonet, Pascal; Frénéa-Robin, Marie

    2017-04-01

    Magnetism and microfluidics are two key elements for the development of inexpensive and reliable tools dedicated to high-throughput biological analysis and providing a large panel of applications in domains ranging from fundamental biology to medical diagnostics. In this work, we introduce a simple protocol, relying on injection molding and reversible bonding for fabrication of magnetic cell trapping and sorting devices using only standard soft-lithography equipment. Magnetic strips or grids made of Polydimethylsiloxane (PDMS) doped with hard (NdFeB) or soft (carbonyl iron) magnetic powders were integrated at the bottom of whole PDMS chips. Preliminary results show the effective deviation/trapping of magnetic beads or magnetically-labeled bacteria as the sample flows through the microchannel, proving the potential of this rapid prototyping approach for easy fabrication of magnetic cell sorters.

  19. Design of activation counter cell for counting of fast neutrons produced by plasma focus device

    International Nuclear Information System (INIS)

    Rajabi Moghadam, S.; Abbasi Davani, F.

    2009-01-01

    In this paper two geometries for pulsed neutron counter structure have been introduced and to increase the activation counter efficiency, plastic scintillation along with silver foils was used. Cubic and cylindrical geometries for activation counter cell were modeled using MCNP4C code. In respect of absorption reaction rate in silver, the number of silver foils and the length of the counter were optimized. The optimum length of 14 centimeters had been proposed for counter cell and because of the economic aspects, the optimum number of silver foils for cubic and cylindrical geometries are 20 and 10, respectively. The optimum data were used to construct a cubic counter and the neutron yield of SBUPF1 plasma focus device was measured by this counter. Experimental results show that about 3.71*10 7 neutrons are produced per pulse.

  20. Development of a miniature autofluorescence device for the early diagnosis of squamous cell carcinoma

    Science.gov (United States)

    Patil, Ajeetkumar; Rao K., Swati; V. K., Unnikrishnan; Pai, Keerthilatha M.; Kartha, V. B.; Chidangil, Santhosh

    2017-07-01

    Autofluorescence spectroscopy offer noninvasive and promising tools for the detection of alternations biochemical compositions of tissues and cells, in presence of disease. They have the added advantage of being highly objective due to the fact that diagnostic evaluation is by statistical methods, eliminating errors from lack of experience, fatigue factor, and subjectivity of visual perceptions. The present research work involves in designing and assembling of a low cost, miniature oral cancer screening device with for routine clinical applications. A miniature system was designed and assembled with much smaller and cost-effective components like compact light source and miniature spectrometer, in a hand-held unit configuration. The performance of the system was evaluated using animal -mouse- SCC model. The current system can be used in handheld operation, which makes it very useful for many applications like, screening of squamous cell carcinoma susceptible population.

  1. Role of Molecular Weight on the Mechanical Device Properties of Organic Polymer Solar Cells

    KAUST Repository

    Bruner, Christopher

    2014-02-11

    For semiconducting polymers, such as regioregular poly(3-hexylthiophene-2, 5-diyl) (rr-P3HT), the molecular weight has been correlated to charge carrier field-effect mobilities, surface morphology, and gelation rates in solution and therefore has important implications for long-Term reliability, manufacturing, and future applications of electronic organic thin films. In this work, we show that the molecular weight rr-P3HT in organic solar cells can also significantly change the internal cohesion of the photoactive layer using micromechanical testing techniques. Cohesive values ranged from ∼0.5 to ∼17 J m -2, following the general trend of greater cohesion with increasing molecular weight. Using nanodynamic mechanical analysis, we attribute the increase in cohesion to increased plasticity which helps dissipate the applied energy. Finally, we correlate photovoltaic efficiency with cohesion to assess the device physics pertinent to optimizing device reliability. This research elucidates the fundamental parameters which affect both the mechanical stability and efficiency of polymer solar cells. © 2014 American Chemical Society.

  2. A cell impedance measurement device for the cytotoxicity assay dependent on the velocity of supplied toxic fluid

    Science.gov (United States)

    Kang, Yoon-Tae; Kim, Min-Ji; Cho, Young-Ho

    2018-04-01

    We present a cell impedance measurement chip capable of characterizing the toxic response of cells depending on the velocity of the supplied toxic fluid. Previous impedance-based devices using a single open-top chamber have been limited to maintaining a constant supply velocity, and devices with a single closed-top chamber present difficulties in simultaneous cytotoxicity assay for varying levels of supply velocities. The present device, capable of generating constant and multiple levels of toxic fluid velocity simultaneously within a single stepwise microchannel, performs a cytotoxicity assay dependent on toxic fluid velocity, in order to find the effective velocity of toxic fluid to cells for maximizing the cytotoxic effect. We analyze the cellular toxic response of 5% ethanol media supplied to cancer cells within a toxic fluid velocity range of 0-8.3 mm s-1. We observe the velocity-dependent cell detachment rate, impedance, and death rate. We find that the cell detachment rate decreased suddenly to 2.4% at a velocity of 4.4 mm s-1, and that the change rates of cell resistance and cell capacitance showed steep decreases to 8% and 41%, respectively, at a velocity of 5.7 mm s-1. The cell death rate and impedance fell steeply to 32% at a velocity of 5.7 mm s-1. We conclude that: (1) the present device is useful in deciding on the toxic fluid velocity effective to cytotoxicity assay, since the cellular toxic response is dependent on the velocity of toxic fluid, and; (2) the cell impedance analysis facilitates a finer cellular response analysis, showing better correlation with the cell death rate, compared to conventional visual observation. The present device, capable of performing the combinational analysis of toxic fluid velocity and cell impedance, has potential for application to the fine cellular toxicity assay of drugs with proper toxic fluid velocity.

  3. Stratification of alpha ganglion cells and ON/OFF directionally selective ganglion cells in the rabbit retina

    OpenAIRE

    ZHANG, JIAN; LI, WEI; HOSHI, HIDEO; MILLS, STEPHEN L.; MASSEY, STEPHEN C.

    2005-01-01

    The correlation between cholinergic sensitivity and the level of stratification for ganglion cells was examined in the rabbit retina. As examples, we have used ON or OFF α ganglion cells and ON/OFF directionally selective (DS) ganglion cells. Nicotine, a cholinergic agonist, depolarized ON/OFF DS ganglion cells and greatly enhanced their firing rates but it had modest excitatory effects on ON or OFF α ganglion cells. As previously reported, we conclude that DS ganglion cells are the most sens...

  4. Single cell dual adherent-suspension co-culture micro-environment for studying tumor-stromal interactions with functionally selected cancer stem-like cells.

    Science.gov (United States)

    Chen, Yu-Chih; Zhang, Zhixiong; Fouladdel, Shamileh; Deol, Yadwinder; Ingram, Patrick N; McDermott, Sean P; Azizi, Ebrahim; Wicha, Max S; Yoon, Euisik

    2016-08-07

    Considerable evidence suggests that cancer stem-like cells (CSCs) are critical in tumor pathogenesis, but their rarity and transience has led to much controversy about their exact nature. Although CSCs can be functionally identified using dish-based tumorsphere assays, it is difficult to handle and monitor single cells in dish-based approaches; single cell-based microfluidic approaches offer better control and reliable single cell derived sphere formation. However, like normal stem cells, CSCs are heavily regulated by their microenvironment, requiring tumor-stromal interactions for tumorigenic and proliferative behaviors. To enable single cell derived tumorsphere formation within a stromal microenvironment, we present a dual adherent/suspension co-culture device, which combines a suspension environment for single-cell tumorsphere assays and an adherent environment for co-culturing stromal cells in close proximity by selectively patterning polyHEMA in indented microwells. By minimizing dead volume and improving cell capture efficiency, the presented platform allows for the use of small numbers of cells (<100 cells). As a proof of concept, we co-cultured single T47D (breast cancer) cells and primary cancer associated fibroblasts (CAF) on-chip for 14 days to monitor sphere formation and growth. Compared to mono-culture, co-cultured T47D have higher tumorigenic potential (sphere formation rate) and proliferation rates (larger sphere size). Furthermore, 96-multiplexed single-cell transcriptome analyses were performed to compare the gene expression of co-cultured and mono-cultured T47D cells. Phenotypic changes observed in co-culture correlated with expression changes in genes associated with proliferation, apoptotic suppression, tumorigenicity and even epithelial-to-mesechymal transition. Combining the presented platform with single cell transcriptome analysis, we successfully identified functional CSCs and investigated the phenotypic and transcriptome effects induced

  5. Regulatory domain selectivity in the cell-type specific PKN-dependence of cell migration.

    Directory of Open Access Journals (Sweden)

    Sylvie Lachmann

    Full Text Available The mammalian protein kinase N (PKN family of Serine/Threonine kinases comprises three isoforms, which are targets for Rho family GTPases. Small GTPases are major regulators of the cellular cytoskeleton, generating interest in the role(s of specific PKN isoforms in processes such as cell migration and invasion. It has been reported that PKN3 is required for prostate tumour cell invasion but not PKN1 or 2. Here we employ a cell model, the 5637 bladder tumour cell line where PKN2 is relatively highly expressed, to assess the potential redundancy of these isoforms in migratory responses. It is established that PKN2 has a critical role in the migration and invasion of these cells. Furthermore, using a PKN wild-type and chimera rescue strategy, it is shown that PKN isoforms are not simply redundant in supporting migration, but appear to be linked through isoform specific regulatory domain properties to selective upstream signals. It is concluded that intervention in PKNs may need to be directed at multiple isoforms to be effective in different cell types.

  6. Regulatory domain selectivity in the cell-type specific PKN-dependence of cell migration.

    Science.gov (United States)

    Lachmann, Sylvie; Jevons, Amy; De Rycker, Manu; Casamassima, Adele; Radtke, Simone; Collazos, Alejandra; Parker, Peter J

    2011-01-01

    The mammalian protein kinase N (PKN) family of Serine/Threonine kinases comprises three isoforms, which are targets for Rho family GTPases. Small GTPases are major regulators of the cellular cytoskeleton, generating interest in the role(s) of specific PKN isoforms in processes such as cell migration and invasion. It has been reported that PKN3 is required for prostate tumour cell invasion but not PKN1 or 2. Here we employ a cell model, the 5637 bladder tumour cell line where PKN2 is relatively highly expressed, to assess the potential redundancy of these isoforms in migratory responses. It is established that PKN2 has a critical role in the migration and invasion of these cells. Furthermore, using a PKN wild-type and chimera rescue strategy, it is shown that PKN isoforms are not simply redundant in supporting migration, but appear to be linked through isoform specific regulatory domain properties to selective upstream signals. It is concluded that intervention in PKNs may need to be directed at multiple isoforms to be effective in different cell types.

  7. Efficient kesterite solar cells with high open-circuit voltage for applications in powering distributed devices

    Science.gov (United States)

    Antunez, Priscilla D.; Bishop, Douglas M.; Luo, Yu; Haight, Richard

    2017-11-01

    Simultaneously achieving high voltage and high efficiency in thin-film solar cells is of paramount importance for real-world applications. While solar cells fabricated from the Earth-abundant kesterite absorber Cu2ZnSn(SxSe1-x)4 provide an attractive, non-toxic, energy harvesting solution, their utilization has been constrained by relatively low open-circuit voltages that limit efficiency. Increasing the sulfur content to widen the bandgap boosts the voltage, but usually at the expense of efficiency. Here, we report important progress on this fundamental problem by fabricating solar cells with high sulfur content that exhibit efficiencies up to 11.89% with open-circuit voltages as high as 670 mV. In a multistep process, fully functional solar cells are separated from their growth substrate, and a high-work-function back contact is subsequently deposited. With this approach, we fabricated a series-connected device that produces 5.7 V under 1 Sun illumination and 2 V under low lighting conditions, below 10-3 Suns.

  8. A bioartificial renal tubule device embedding human renal stem/progenitor cells.

    Directory of Open Access Journals (Sweden)

    Anna Giovanna Sciancalepore

    Full Text Available We present a bio-inspired renal microdevice that resembles the in vivo structure of a kidney proximal tubule. For the first time, a population of tubular adult renal stem/progenitor cells (ARPCs was embedded into a microsystem to create a bioengineered renal tubule. These cells have both multipotent differentiation abilities and an extraordinary capacity for injured renal cell regeneration. Therefore, ARPCs may be considered a promising tool for promoting regenerative processes in the kidney to treat acute and chronic renal injury. Here ARPCs were grown to confluence and exposed to a laminar fluid shear stress into the chip, in order to induce a functional cell polarization. Exposing ARPCs to fluid shear stress in the chip led the aquaporin-2 transporter to localize at their apical region and the Na(+K(+ATPase pump at their basolateral portion, in contrast to statically cultured ARPCs. A recovery of urea and creatinine of (20±5% and (13±5%, respectively, was obtained by the device. The microengineered biochip here-proposed might be an innovative "lab-on-a-chip" platform to investigate in vitro ARPCs behaviour or to test drugs for therapeutic and toxicological responses.

  9. Preliminary evaluation of nickel/cadmium cells for a totally implantable ventricular assist device

    Science.gov (United States)

    Shu, Zhi Xin; Aiken, Peter A.; MacLean, Gregory K.; Adams, William A.

    A preliminary evaluation on the performance characteristics of three types of Ni/Cd cells was carried out in order to determine their potential usefulness in the internal (implantable) battery for the electrohydraulic ventricular assist device (EVAD) being developed at the University of Ottawa Heart Institute and University of Utah. The parameters studied at 37 °C were memory effect, discharge rate capability, self-discharge, surface temperature increase during charge and discharge and cycle life under the average power drain of the EVAD. Standard cells (designated 'S'), which were designed for room temperature use, suffered from a memory effect and had a low cycle life (114 cycles) and were, therefore, rejected for use in the EVAD. Two other types of cells (designated 'P' and 'H'), which were designed for higher temperature use, were comparable in their overall performance showing little or no memory effect and good cycle life (514 and 358 cycles, respectively). These latter two types of cells could be potential candidates for use in EVAD's internal battery.

  10. Field Performance versus Standard Test Condition Efficiency of Tandem Solar Cells and the Specific Case of Perovskites/Silicon Devices

    KAUST Repository

    Dupre, Olivier

    2018-01-05

    Multijunction cells may offer a cost-effective route to boost the efficiency of industrial photovoltaics. For any technology to be deployed in the field, its performance under actual operating conditions is extremely important. In this perspective, we evaluate the impact of spectrum, light intensity, and module temperature variations on the efficiency of tandem devices with crystalline silicon bottom cells with a particular focus on perovskite top cells. We consider devices with different efficiencies and calculate their energy yields using field data from Denver. We find that annual losses due to differences between operating conditions and standard test conditions are similar for single-junction and four-terminal tandem devices. The additional loss for the two-terminal tandem configuration caused by current mismatch reduces its performance ratio by only 1.7% when an optimal top cell bandgap is used. Additionally, the unusual bandgap temperature dependence of perovskites is shown to have a positive, compensating effect on current mismatch.

  11. Catch and Patch: A Pipette-Based Approach for Automating Patch Clamp That Enables Cell Selection and Fast Compound Application.

    Science.gov (United States)

    Danker, Timm; Braun, Franziska; Silbernagl, Nikole; Guenther, Elke

    2016-03-01

    Manual patch clamp, the gold standard of electrophysiology, represents a powerful and versatile toolbox to stimulate, modulate, and record ion channel activity from membrane fragments and whole cells. The electrophysiological readout can be combined with fluorescent or optogenetic methods and allows for ultrafast solution exchanges using specialized microfluidic tools. A hallmark of manual patch clamp is the intentional selection of individual cells for recording, often an essential prerequisite to generate meaningful data. So far, available automation solutions rely on random cell usage in the closed environment of a chip and thus sacrifice much of this versatility by design. To parallelize and automate the traditional patch clamp technique while perpetuating the full versatility of the method, we developed an approach to automation, which is based on active cell handling and targeted electrode placement rather than on random processes. This is achieved through an automated pipette positioning system, which guides the tips of recording pipettes with micrometer precision to a microfluidic cell handling device. Using a patch pipette array mounted on a conventional micromanipulator, our automated patch clamp process mimics the original manual patch clamp as closely as possible, yet achieving a configuration where recordings are obtained from many patch electrodes in parallel. In addition, our implementation is extensible by design to allow the easy integration of specialized equipment such as ultrafast compound application tools. The resulting system offers fully automated patch clamp on purposely selected cells and combines high-quality gigaseal recordings with solution switching in the millisecond timescale.

  12. Thermally evaporated thin films of SnS for application in solar cell devices

    International Nuclear Information System (INIS)

    Miles, Robert W.; Ogah, Ogah E.; Zoppi, Guillaume; Forbes, Ian

    2009-01-01

    SnS (tin sulphide) is of interest for use as an absorber layer and the wider energy bandgap phases e.g. SnS 2 , Sn 2 S 3 and Sn/S/O alloys of interest as Cd-free buffer layers for use in thin film solar cells. In this work thin films of tin sulphide have been thermally evaporated onto glass and SnO 2 :coated glass substrates with the aim of optimising the properties of the material for use in photovoltaic solar cell device structures. In particular the effects of source temperature, substrate temperature, deposition rate and film thickness on the chemical and physical properties of the layers were investigated. Energy dispersive X-ray analysis was used to determine the film composition, X-ray diffraction to determine the phases present and structure of each phase, transmittance and reflectance versus wavelength measurements to determine the energy bandgap and scanning electron microscopy to observe the surface topology and topography and the properties correlated to the deposition parameters. Using the optimised conditions it is possible to produce thin films of tin sulphide that are pinhole free, conformal to the substrate and that consist of densely packed columnar grains. The composition, phases present and the optical properties of the layers deposited were found to be highly sensitive to the deposition conditions. Energy bandgaps in the range 1.55 eV-1.7 eV were obtained for a film thickness of 0.8 μm, and increasing the film thickness to > 1 μm resulted in a reduction of the energy bandgap to less than 1.55 eV. The applicability of using these films in photovoltaic solar cell device structures is also discussed.

  13. Resveratrol Sensitizes Selectively Thyroid Cancer Cell to 131-Iodine Toxicity

    Directory of Open Access Journals (Sweden)

    Seyed Jalal Hosseinimehr

    2014-01-01

    Full Text Available Background. In this study, the radiosensitizing effect of resveratrol as a natural product was investigated on cell toxicity induced by 131I in thyroid cancer cell. Methods. Human thyroid cancer cell and human nonmalignant fibroblast cell (HFFF2 were treated with 131I and/or resveratrol at different concentrations for 48 h. The cell proliferation was measured by determination of the percent of the survival cells using 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT assay. Results. Findings of this study show that resveratrol enhanced the cell death induced by 131I on thyroid cancer cell. Also, resveratrol exhibited a protective effect on normal cells against 131I toxicity. Conclusion. This result indicates a promising effect of resveratrol on improvement of cellular toxicity during iodine therapy.

  14. Selectively Transparent and Conducting Photonic Crystals and their Potential to Enhance the Performance of Thin-Film Silicon-Based Photovoltaics and Other Optoelectronic Devices

    Science.gov (United States)

    O'Brien, Paul G.

    2011-12-01

    The byproducts of human engineered energy production are increasing atmospheric CO2 concentrations well above their natural levels and accompanied continual decline in the natural reserves of fossil fuels necessitates the development of green energy alternatives. Solar energy is attractive because it is abundant, can be produced in remote locations and consumed on site. Specifically, thin-film silicon-based photovoltaic (PV) solar cells have numerous inherent advantages including their availability, non-toxicity, and they are relatively inexpensive. However, their low-cost and electrical performance depends on reducing their thickness to as great an extent as possible. This is problematic because their thickness is much less than their absorption length. Consequently, enhanced light trapping schemes must be incorporated into these devices. Herein, a transparent and conducting photonic crystal (PC) intermediate reflector (IR), integrated into the rear side of the cell and serving the dual function as a back-reflector and a spectral splitter, is identified as a promising method of boosting the performance of thin-film silicon-based PV. To this end a novel class of PCs, namely selectively transparent and conducting photonic crystals (STCPC), is invented. These STCPCs are a significant advance over existing 1D PCs because they combine intense wavelength selective broadband reflectance with the transmissive and conductive properties of sputtered ITO. For example, STCPCs are made to exhibit Bragg-reflectance peaks in the visible spectrum of 95% reflectivity and have a full width at half maximum that is greater than 200nm. At the same time, the average transmittance of these STCPCs is greater than 80% over the visible spectrum that is outside their stop-gap. Using wave-optics analysis, it is shown that STCPC intermediate reflectors increase the current generated in micromorph cells by 18%. In comparison, the more conventional IR comprised of a single homogeneous

  15. Group 3 innate lymphoid cells mediate intestinal selection of commensal bacteria-specific CD4+ T cells

    Science.gov (United States)

    Hepworth, Matthew R.; Fung, Thomas C.; Masur, Samuel H.; Kelsen, Judith R.; McConnell, Fiona M.; Dubrot, Juan; Withers, David R.; Hugues, Stephanie; Farrar, Michael A.; Reith, Walter; Eberl, Gerard; Baldassano, Robert N.; Laufer, Terri M.; Elson, Charles O.; Sonnenberg, Gregory F.

    2015-01-01

    Inflammatory CD4+ T cell responses to self or commensal bacteria underlie the pathogenesis of autoimmunity and inflammatory bowel disease (IBD), respectively. While selection of self-specific T cells in the thymus limits responses to tissue antigens, the mechanisms that control selection of commensal bacteria-specific T cells remain poorly understood. Here we demonstrate that group 3 innate lymphoid cell (ILC3)-intrinsic expression of major histocompatibility complex class II (MHCII) is regulated similarly to thymic epithelial cells, and that MHCII+ ILC3s directly induce cell death of activated commensal bacteria-specific T cells. Further, MHCII on human colonic ILC3s was reduced in pediatric IBD patients. Collectively, these results define a selection pathway for commensal bacteria-specific CD4+ T cells in the intestine, and suggest that this process is dysregulated in human IBD. PMID:25908663

  16. A Flow-Through Cell Electroporation Device for Rapidly and Efficiently Transfecting Massive Amounts of Cells in vitro and ex vivo

    Science.gov (United States)

    Zhao, Deyao; Huang, Dong; Li, Yang; Wu, Mengxi; Zhong, Wenfeng; Cheng, Qiang; Wang, Xiaoxia; Wu, Yidi; Zhou, Xiao; Wei, Zewen; Li, Zhihong; Liang, Zicai

    2016-01-01

    Continuous cell electroporation is an appealing non-viral approach for genetically transfecting a large number of cells. Yet the traditional macro-scale devices suffer from the unsatisfactory transfection efficiency and/or cell viability due to their high voltage, while the emerging microfluidic electroporation devices is still limited by their low cell processing speed. Here we present a flow-through cell electroporation device integrating large-sized flow tube and small-spaced distributed needle electrode array. Relatively large flow tube enables high flow rate, simple flow characterization and low shear force, while well-organized needle array electrodes produce an even-distributed electric field with low voltage. Thus the difficulties for seeking the fine balance between high flow rate and low electroporation voltage were steered clear. Efficient in vitro electrotransfection of plasmid DNA was demonstrated in several hard-to-transfect cell lines. Furthermore, we also explored ex vivo electroporated mouse erythrocyte as the carrier of RNA. The strong ability of RNA loading and short exposure time of freshly isolated cells jointly ensured a high yield of valid carrier erythrocytes, which further successfully delivered RNA into targeted tissue. Both in vitro and ex vivo electrotransfection could be accomplished at high cell processing speed (20 million cells per minute) which remarkably outperforms previous devices.

  17. 3D printed disposable optics and lab-on-a-chip devices for chemical sensing with cell phones

    Science.gov (United States)

    Comina, G.; Suska, A.; Filippini, D.

    2017-02-01

    Digital manufacturing (DM) offers fast prototyping capabilities and great versatility to configure countless architectures at affordable development costs. Autonomous lab-on-a-chip (LOC) devices, conceived as only disposable accessory to interface chemical sensing to cell phones, require specific features that can be achieved using DM techniques. Here we describe stereo-lithography 3D printing (SLA) of optical components and unibody-LOC (ULOC) devices using consumer grade printers. ULOC devices integrate actuation in the form of check-valves and finger pumps, as well as the calibration range required for quantitative detection. Coupling to phone camera readout depends on the detection approach, and includes different types of optical components. Optical surfaces can be locally configured with a simple polishing-free post-processing step, and the representative costs are 0.5 US$/device, same as ULOC devices, both involving fabrication times of about 20 min.

  18. An electronic image processing device featuring continuously selectable two-dimensional bipolar filter functions and real-time operation

    International Nuclear Information System (INIS)

    Charleston, B.D.; Beckman, F.H.; Franco, M.J.; Charleston, D.B.

    1981-01-01

    A versatile electronic-analogue image processing system has been developed for use in improving the quality of various types of images with emphasis on those encountered in experimental and diagnostic medicine. The operational principle utilizes spatial filtering which selectively controls the contrast of an image according to the spatial frequency content of relevant and non-relevant features of the image. Noise can be reduced or eliminated by selectively lowering the contrast of information in the high spatial frequency range. Edge sharpness can be enhanced by accentuating the upper midrange spatial frequencies. Both methods of spatial frequency control may be adjusted continuously in the same image to obtain maximum visibility of the features of interest. A precision video camera is used to view medical diagnostic images, either prints, transparencies or CRT displays. The output of the camera provides the analogue input signal for both the electronic processing system and the video display of the unprocessed image. The video signal input to the electronic processing system is processed by a two-dimensional spatial convolution operation. The system employs charged-coupled devices (CCDs), both tapped analogue delay lines (TADs) and serial analogue delay lines (SADs), to store information in the form of analogue potentials which are constantly being updated as new sampled analogue data arrive at the input. This information is convolved with a programmed bipolar radially symmetrical hexagonal function which may be controlled and varied at each radius by the operator in real-time by adjusting a set of front panel controls or by a programmed microprocessor control. Two TV monitors are used, one for processed image display and the other for constant reference to the original image. The working prototype has a full-screen display matrix size of 200 picture elements per horizontal line by 240 lines. The matrix can be expanded vertically and horizontally for the

  19. Dendritic relationship between starburst amacrine cells and direction-selective ganglion cells in the rabbit retina.

    Science.gov (United States)

    Dong, Wei; Sun, Wenzhi; Zhang, Yingye; Chen, Xiaorong; He, Shigang

    2004-04-01

    We investigated the dendritic relationship between starburst amacrine cells (SAs) and morphologically and physiologically characterized ON and ON-OFF direction-selective ganglion cells (DSGCs) in the rabbit retina. ON and ON-OFF DSGCs were found to exhibit tight dendritic cofasciculation with the SA plexus, visualized by immunolabelling of the vesicular acetylcholine transporter (VAChT). The degree of cofasciculation of both types of DSGC dendrites and SA plexus was found to be significant, unlike the relationship between non-DS cells and the SA plexus, which was close to chance distribution. No difference in the degree of cofasciculation in different regions of the DS dendritic field was observed. Individual SAs intracellularly injected both on the 'preferred' and 'null' side of the DSGCs showed the same degree of cofasciculation with the DSGCs. Therefore, the computation of motion direction is unlikely to result from apparent asymmetry in geometric proximity between SAs and DSGCs. Highly selective synaptic connections between SAs and DSGCs are necessary.

  20. Template-assisted selective epitaxy of III–V nanoscale devices for co-planar heterogeneous integration with Si

    Energy Technology Data Exchange (ETDEWEB)

    Schmid, H., E-mail: sih@zurich.ibm.com; Borg, M.; Moselund, K.; Cutaia, D.; Riel, H. [IBM Research – Zurich, 8803 Rüschlikon (Switzerland); Gignac, L.; Breslin, C. M.; Bruley, J. [IBM Research – T. J. Watson Research Center, Yorktown Heights, New York 10598 (United States)

    2015-06-08

    III–V nanoscale devices were monolithically integrated on silicon-on-insulator (SOI) substrates by template-assisted selective epitaxy (TASE) using metal organic chemical vapor deposition. Single crystal III–V (InAs, InGaAs, GaAs) nanostructures, such as nanowires, nanostructures containing constrictions, and cross junctions, as well as 3D stacked nanowires were directly obtained by epitaxial filling of lithographically defined oxide templates. The benefit of TASE is exemplified by the straightforward fabrication of nanoscale Hall structures as well as multiple gate field effect transistors (MuG-FETs) grown co-planar to the SOI layer. Hall measurements on InAs nanowire cross junctions revealed an electron mobility of 5400 cm{sup 2}/V s, while the alongside fabricated InAs MuG-FETs with ten 55 nm wide, 23 nm thick, and 390 nm long channels exhibit an on current of 660 μA/μm and a peak transconductance of 1.0 mS/μm at V{sub DS} = 0.5 V. These results demonstrate TASE as a promising fabrication approach for heterogeneous material integration on Si.

  1. Using injection molding and reversible bonding for easy fabrication of magnetic cell trapping and sorting devices

    Energy Technology Data Exchange (ETDEWEB)

    Royet, David; Hériveaux, Yoann; Marchalot, Julien; Scorretti, Riccardo [Univ Lyon, ECL, UCB Lyon1, CNRS, Ampere, F-69134 Ecully (France); Dias, André; Dempsey, Nora M. [Univ. Grenoble Alpes - CNRS, Inst Neel, F-38042 Grenoble (France); Bonfim, Marlio [Universidade Federal do Paraná, DELT, Curitiba (Brazil); Simonet, Pascal; Frénéa-Robin, Marie [Univ Lyon, ECL, UCB Lyon1, CNRS, Ampere, F-69134 Ecully (France)

    2017-04-01

    Magnetism and microfluidics are two key elements for the development of inexpensive and reliable tools dedicated to high-throughput biological analysis and providing a large panel of applications in domains ranging from fundamental biology to medical diagnostics. In this work, we introduce a simple protocol, relying on injection molding and reversible bonding for fabrication of magnetic cell trapping and sorting devices using only standard soft-lithography equipment. Magnetic strips or grids made of Polydimethylsiloxane (PDMS) doped with hard (NdFeB) or soft (carbonyl iron) magnetic powders were integrated at the bottom of whole PDMS chips. Preliminary results show the effective deviation/trapping of magnetic beads or magnetically-labeled bacteria as the sample flows through the microchannel, proving the potential of this rapid prototyping approach for easy fabrication of magnetic cell sorters. - Highlights: • Soft and hard magnetic PDMS composites were microstructured by injection molding. • Tunable or autonomous magnetic microdevices can be fabricated using this approach. • Continuous-flow bacterial cell trapping and deviation were demonstrated.

  2. Using injection molding and reversible bonding for easy fabrication of magnetic cell trapping and sorting devices

    International Nuclear Information System (INIS)

    Royet, David; Hériveaux, Yoann; Marchalot, Julien; Scorretti, Riccardo; Dias, André; Dempsey, Nora M.; Bonfim, Marlio; Simonet, Pascal; Frénéa-Robin, Marie

    2017-01-01

    Magnetism and microfluidics are two key elements for the development of inexpensive and reliable tools dedicated to high-throughput biological analysis and providing a large panel of applications in domains ranging from fundamental biology to medical diagnostics. In this work, we introduce a simple protocol, relying on injection molding and reversible bonding for fabrication of magnetic cell trapping and sorting devices using only standard soft-lithography equipment. Magnetic strips or grids made of Polydimethylsiloxane (PDMS) doped with hard (NdFeB) or soft (carbonyl iron) magnetic powders were integrated at the bottom of whole PDMS chips. Preliminary results show the effective deviation/trapping of magnetic beads or magnetically-labeled bacteria as the sample flows through the microchannel, proving the potential of this rapid prototyping approach for easy fabrication of magnetic cell sorters. - Highlights: • Soft and hard magnetic PDMS composites were microstructured by injection molding. • Tunable or autonomous magnetic microdevices can be fabricated using this approach. • Continuous-flow bacterial cell trapping and deviation were demonstrated.

  3. System Design and Development of a Robotic Device for Automated Venipuncture and Diagnostic Blood Cell Analysis.

    Science.gov (United States)

    Balter, Max L; Chen, Alvin I; Fromholtz, Alex; Gorshkov, Alex; Maguire, Tim J; Yarmush, Martin L

    2016-10-01

    Diagnostic blood testing is the most prevalent medical procedure performed in the world and forms the cornerstone of modern health care delivery. Yet blood tests are still predominantly carried out in centralized labs using large-volume samples acquired by manual venipuncture, and no end-to-end solution from blood draw to sample analysis exists today. Our group is developing a platform device that merges robotic phlebotomy with automated diagnostics to rapidly deliver patient information at the site of the blood draw. The system couples an image-guided venipuncture robot, designed to address the challenges of routine venous access, with a centrifuge-based blood analyzer to obtain quantitative measurements of hematology. In this paper, we first present the system design and architecture of the integrated device. We then perform a series of in vitro experiments to evaluate the cannulation accuracy of the system on blood vessel phantoms. Next, we assess the effects of vessel diameter, needle gauge, flow rate, and viscosity on the rate of sample collection. Finally, we demonstrate proof-of-concept of a white cell assay on the blood analyzer using in vitro human samples spiked with fluorescently labeled microbeads.

  4. Cell-phone-based platform for biomedical device development and education applications.

    Directory of Open Access Journals (Sweden)

    Zachary J Smith

    Full Text Available In this paper we report the development of two attachments to a commercial cell phone that transform the phone's integrated lens and image sensor into a 350x microscope and visible-light spectrometer. The microscope is capable of transmission and polarized microscopy modes and is shown to have 1.5 micron resolution and a usable field-of-view of 150 x 50 with no image processing, and approximately 350 x 350 when post-processing is applied. The spectrometer has a 300 nm bandwidth with a limiting spectral resolution of close to 5 nm. We show applications of the devices to medically relevant problems. In the case of the microscope, we image both stained and unstained blood-smears showing the ability to acquire images of similar quality to commercial microscope platforms, thus allowing diagnosis of clinical pathologies. With the spectrometer we demonstrate acquisition of a white-light transmission spectrum through diffuse tissue as well as the acquisition of a fluorescence spectrum. We also envision the devices to have immediate relevance in the educational field.

  5. Preliminary evaluation of rechargeable lithium cells for a totally-implantable ventricular assist device

    Science.gov (United States)

    MacLean, Gregory K.; Xin Shu, Zhi; Aiken, Peter A.; Eng, Isaac I.; Adams, William A.

    A preliminary evaluation of the performance characteristics for three types of rechargeable, 'AA' size, lithium cell chemistries, namely Li/TiS 2 (two different manufacturers), Li/MoS 2 and Li/MnO 2, was carried out in order to determine their potential usefulness in the internal (implanted) battery for the electrohydraulic ventricular assist device (EVAD) being developed. The major parameters studied at 37 °C were discharge rate capability, self-discharge and cycle life. The cycle life of the lithium cells above the minimum 30 min discharge time specified for EVAD were short, with the Li/MoS 2, Li/MnO 2 and two Li/TiS 2 cells giving 80, ˜ 11, 37 and 101 cycles, respectively, under pulsed discharge conditions. The 24 H, self-discharge study of all the cells at 37 °C showed < 1.2% decrease in capacity. Discharge rate studies showed that the Li/TiS 2 cells from both manufacturers offered higher observed specific energies (85 and 133 W h/kg) and energy densities (203 and 273 W h/l), lower internal resistances (155 and 84 mΩ) and larger observed capacities (0.83 and 1.00 A h) when compared to the Li/MoS 2 (49 W h/kg, 126 W h/l, 153 mΩ and 0.58 A h, respectively) and Li/MnO 2 (56 W h/kg, 131 W h/l, 350 mΩ and 0.39 A h, respectively) cells operating under average EVAD load conditions. The cycle life and operating times of cells that were pulse discharged to mimic actual EVAD operating conditions were shorter than those that underwent cycling with an average EVAD load. When compared to other energy sources and the EVAD design specification, it was concluded that none of these prototype lithium cells were currently suitable for use in the EVAD due to their low cycle life.

  6. Characterization of Organic Solar Cell Devices and their Interfaces under Degradation: Imaging, Electrical and Mechanical Methods

    DEFF Research Database (Denmark)

    Corazza, Michael

    energy is one of the answers for renewable energy. In this thesis, the research has been conducted on polymer solar cells. In particular, the thesis deals with the extensive study of device lifetime, characterized with several methods: from bare benchmarking of the lifetimes, to more advanced......Renewable energies are a critical and necessary technological development deeply connected to human evolution and even survival. The extraordinary technological development of the past century brought tremendous changes to the planet which, despite the scepticism of some, are indubitably affecting...... the natural ecosystem and maybe even the destiny of Earth. Human evolution does not mean only advanced technological development, but also deeper consciousness and responsibility for the next generations to come. Everything on Earth exists because of the Sun: heat, wind, life... everything. Therefore, solar...

  7. Lifetime limiting effects in pre-commercial solid oxide cell devices

    DEFF Research Database (Denmark)

    Skafte, Theis Løye

    of degradationand lifetime was conducted. It is shown that the technology is approaching the officialtargets required for commercialization, but that work remains to be done.  It is further recognized that targeting nicheapplications initially will allow for employment of economies of scale, whichwill bring down......The solidoxide electrochemical cell technology is promising for efficient energy storage,especially when the share of intermittent renewable electricity production ishigh. The technology is being commercialized in niche markets, but large-scale employmentis still hindered by limited durability...... of the devices. The lifetime limitingmechanisms are addressed in this work. A generalintroduction into mechanisms limiting the durability is presented. A databaseof more than 50 parameters from 150 publications and 1 000 000 hours ofaccumulated testing was established, and a quantitative analysis...

  8. All-magnetic magnetoresistive random access memory based on four terminal mCell device

    Science.gov (United States)

    Bromberg, D. M.; Sumbul, H. E.; Zhu, J.-G.; Pileggi, L.

    2015-05-01

    Magnetoresistive random access memory (MRAM) is a promising candidate to enable fast, non-volatile storage on chip. In this paper, we present an MRAM design where each bitcell is comprised entirely of four-terminal magnetic devices ("mCells") with no CMOS access transistors. We show that this design can achieve significant energy and area savings compared to the standard one transistor-one magnetic tunnel junction (1T1MTJ) bitcell based design. We estimate a write energy of ≈5 fJ/bit based on bitline and wordline voltages that operate at less than 100 mV with projected area smaller than that possible with aggressively scaled 10 nm node FinFETs in the 1T1MTJ design.

  9. Internal transmission coefficient in charges carrier generation layer of graphene/Si based solar cell device

    Science.gov (United States)

    Rosikhin, Ahmad; Winata, Toto

    2016-04-01

    Internal transmission profile in charges carrier generation layer of graphene/Si based solar cell has been explored theoretically. Photovoltaic device was constructed from graphene/Si heterojunction forming a multilayer stuck with Si as generation layer. The graphene/Si sheet was layered on ITO/glass wafer then coated by Al forming Ohmic contact with Si. Photon incident propagate from glass substrate to metal electrode and assumed that there is no transmission in Al layer. The wavelength range spectra used in this calculation was 200 - 1000 nm. It found that transmission intensity in the generation layer show non-linear behavior and partitioned by few areas which related with excitation process. According to this information, it may to optimize the photons absorption to create more excitation process by inserting appropriate material to enhance optical properties in certain wavelength spectra because of the exciton generation is strongly influenced by photon absorption.

  10. Perovskite Solar Cells: From the Atomic Level to Film Quality and Device Performance.

    Science.gov (United States)

    Saliba, Michael; Correa-Baena, Juan-Pablo; Grätzel, Michael; Hagfeldt, Anders; Abate, Antonio

    2018-03-01

    Organic-inorganic perovskites have made tremendous progress in recent years due to exceptional material properties such as high panchromatic absorption, charge carrier diffusion lengths, and a sharp optical band edge. The combination of high-quality semiconductor performance with low-cost deposition techniques seems to be a match made in heaven, creating great excitement far beyond academic ivory towers. This is particularly true for perovskite solar cells (PSCs) that have shown unprecedented gains in efficiency and stability over a time span of just five years. Now there are serious efforts for commercialization with the hope that PSCs can make a major impact in generating inexpensive, sustainable solar electricity. In this Review, we will focus on perovskite material properties as well as on devices from the atomic to the thin film level to highlight the remaining challenges and to anticipate the future developments of PSCs. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Experimental and theoretical study of hydrodynamic cell lysing of cancer cells in a high-throughput Circular Multi-Channel Microfiltration device

    KAUST Repository

    Ma, W.

    2013-04-01

    Microfiltration is an important microfluidic technique suitable for enrichment and isolation of cells. However, cell lysing could occur due to hydrodynamic damage that may be detrimental for medical diagnostics. Therefore, we conducted a systematic study of hydrodynamic cell lysing in a high-throughput Circular Multi-Channel Microfiltration (CMCM) device integrated with a polycarbonate membrane. HeLa cells (cervical cancer cells) were driven into the CMCM at different flow rates. The viability of the cells in the CMCM was examined by fluorescence microscopy using Acridine Orange (AO)/Ethidium Bromide (EB) as a marker for viable/dead cells. A simple analytical cell viability model was derived and a 3D numerical model was constructed to examine the correlation of between cell lysing and applied shear stress under varying flow rate and Reynolds number. The measured cell viability as a function of the shear stress was consistent with theoretical and numerical predictions when accounting for cell size distribution. © 2013 IEEE.

  12. Effect of chemically converted graphene as an electrode interfacial modifier on device-performances of inverted organic photovoltaic cells

    Science.gov (United States)

    Kang, Tae-Woon; Noh, Yong-Jin; Yun, Jin-Mun; Yang, Si-Young; Yang, Yong-Eon; Lee, Hae-Seong; Na, Seok-In

    2015-06-01

    This study examined the effects of chemically converted graphene (CCG) materials as a metal electrode interfacial modifier on device-performances of inverted organic photovoltaic cells (OPVs). As CCG materials for interfacial layers, a conventional graphene oxide (GO) and reduced graphene oxide (rGO) were prepared, and their functions on OPV-performances were compared. The inverted OPVs with CCG materials showed all improved cell-efficiencies compared with the OPVs with no metal/bulk-heterojunction (BHJ) interlayers. In particular, the inverted OPVs with reduction form of GO showed better device-performances than those with GO and better device-stability than poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS)-based inverted solar cells, showing that the rGO can be more desirable as a metal/BHJ interfacial material for fabricating inverted-configuration OPVs.

  13. Bi-module sensing device to in situ quantitatively detect hydrogen peroxide released from migrating tumor cells.

    Directory of Open Access Journals (Sweden)

    Ling Yu

    Full Text Available Cell migration is one of the key cell functions in physiological and pathological processes, especially in tumor metastasis. However, it is not feasible to monitor the important biochemical molecules produced during cell migrations in situ by conventional cell migration assays. Herein, for the first time a device containing both electrochemical sensing and trans-well cell migration modules was fabricated to sensitively quantify biochemical molecules released from the cell migration process in situ. The fully assembled device with a multi-wall carbon nanotube/graphene/MnO2 nanocomposite functionalized electrode was able to successfully characterize hydrogen peroxide (H2O2 production from melanoma A375 cells, larynx carcinoma HEp-2 cells and liver cancer Hep G2 under serum established chemotaxis. The maximum concentration of H2O2 produced from A375, HEp-2 and Hep G2 in chemotaxis was 130 ± 1.3 nM, 70 ± 0.7 nM and 63 ± 0.7 nM, respectively. While the time required reaching the summit of H2O2 production was 3.0, 4.0 and 1.5 h for A375, HEp-2 and Hep G2, respectively. By staining the polycarbonate micropore membrane disassembled from the device, we found that the average migration rate of the A375, HEp-2 and Hep G2 cells were 98 ± 6%, 38 ± 4% and 32 ± 3%, respectively. The novel bi-module cell migration platform enables in situ investigation of cell secretion and cell function simultaneously, highlighting its potential for characterizing cell motility through monitoring H2O2 production on rare samples and for identifying underlying mechanisms of cell migration.

  14. Cell-to-cell communication competence in simian virus 40-transfected rat ovarian cells is reduced following tumor selection.

    Science.gov (United States)

    Stein, L S; Welsh, T H; Wilson, V G; Burghardt, R C

    1992-06-01

    A pSV3neo-transfected rat ovarian cell line (SV-GC) was developed from a primary granulosa culture (GC) to study gap junctional intercellular communication (GJIC) during Simian virus 40 (SV40) transformation. SV-GC expressed SV40 large T-antigen (T-ag), grew indefinitely in culture without luteinization, was anchorage independent, and formed tumors in nude mice. Ultrastructural analysis identified abundant gap junctional membrane and suggested that SV-GC was arrested at an early stage of differentiation. Functional GJIC, measured by a dye transfer technique (gap FRAP), was comparable to that observed in normal granulosa cells, suggesting that the expression of T-ag alone was insufficient to reduce GJIC. However, there was approximately a 50% loss in the rate of GJIC in the nude mouse SV-GC-tumor derived and G418 selected cell line (T-SV-GC). SV-GC----T-SV-GC also resulted in a transition from migration of cells as an epithelial sheet to the dissociation of individual fibroblastoid cells. Tumor cell detachment was also seen in migrating malignant human (A2780 and 547) and rat (DC3) ovarian cell lines. Co-culture combinations of normal (GC)----transformed (SV-GC)----tumor-derived (T-SV-GC) cells indicated that the rate of heterologous GJIC was characteristic of the least communicating partner. Taken together, these data suggested that SV-GC----T-SV-GC represented progression toward metastasis with concomitant reduction of GJIC and adhesiveness. These sequentially derived cell lines may be a useful in vitro model system for studies focusing on the mechanism involved in the detachment of cells during the progression of ovarian cancer.

  15. Microselection - Affinity Selecting Antibodies against a Single Rare Cell in a Heterogeneous Population

    DEFF Research Database (Denmark)

    Sørensen, Morten Dræby; Agerholm, Inge Errebo; Christensen, Britta

    2009-01-01

    antibodies. Here we have generated a microselection method allowing antibody selection, by phage display, targeting a single cell in a heterogeneous population. One K562 cell (female origin) was positioned on glass-slide among millions of lymphocytes from male donor, identifying the K562 cell by FISH (XX......). Several single cell selections were performed on such individual slides. The phage particles bound to the target cell is protected by a minute disc, while inactivating all remaining phage by UV-irradiation; leaving only the phage bound to the target cell viable. We hereby retrieved up to eight antibodies...

  16. Spectrally-engineered solar thermal photovoltaic devices

    Energy Technology Data Exchange (ETDEWEB)

    Lenert, Andrej; Bierman, David; Chan, Walker; Celanovic, Ivan; Soljacic, Marin; Wang, Evelyn N.; Nam, Young Suk; McEnaney, Kenneth; Kraemer, Daniel; Chen, Gang

    2018-03-27

    A solar thermal photovoltaic device, and method of forming same, includes a solar absorber and a spectrally selective emitter formed on either side of a thermally conductive substrate. The solar absorber is configured to absorb incident solar radiation. The solar absorber and the spectrally selective emitter are configured with an optimized emitter-to-absorber area ratio. The solar thermal photovoltaic device also includes a photovoltaic cell in thermal communication with the spectrally selective emitter. The spectrally selective emitter is configured to permit high emittance for energies above a bandgap of the photovoltaic cell and configured to permit low emittance for energies below the bandgap.

  17. Hard tissue formation of STRO-1-selected rat dental pulp stem cells in vivo.

    NARCIS (Netherlands)

    Yang, X.; Walboomers, X.F.; Beucken, J.J.J.P van den; Bian, Z.; Fan, M.; Jansen, J.A.

    2009-01-01

    The objective of this study was to examine hard tissue formation of STRO-1-selected rat dental pulp-derived stem cells, seeded into a calcium phosphate ceramic scaffold, and implanted subcutaneously in mice. Previously, STRO-1 selection was used to obtain a mesenchymal stem cell progenitor

  18. Recruitment and selection of marginal zone B cells is independent of exogenous antigens

    NARCIS (Netherlands)

    Dammers, PM; Kroese, FGM

    Marginal zone B (MZ-B) cells of the spleen contribute significantly to the immunity against invasive infections with polysaccharide-encapsulated bacteria. Recent evidence indicates that recruitment and selection of MZ-B cells occurs on the basis of positive selection constraints that likely operate

  19. Anomalous electron transport in metal/carbon multijunction devices by engineering of the carbon thickness and selecting metal layer

    Science.gov (United States)

    Dwivedi, Neeraj; Dhand, Chetna; Rawal, Ishpal; Kumar, Sushil; Malik, Hitendra K.; Lakshminarayanan, Rajamani

    2017-06-01

    A longstanding concern in the research of amorphous carbon films is their poor electrical conductivity at room temperature which constitutes a major barrier for the development of cost effective electronic and optoelectronic devices. Here, we propose metal/carbon hybrid multijunction devices as a promising facile way to overcome room temperature electron transport issues in amorphous carbon films. By the tuning of carbon thickness and swapping metal layers, we observe giant (upto ˜7 orders) reduction of electrical resistance in metal/carbon multijunction devices with respect to monolithic amorphous carbon device. We engineer the maximum current (electrical resistance) from about 10-7 to 10-3 A (˜107 to 103 Ω) in metal (Cu or Ti)/carbon hybrid multijunction devices with a total number of 10 junctions. The introduction of thin metal layers breaks the continuity of relatively higher resistance carbon layer as well as promotes the nanostructuring of carbon. These contribute to low electrical resistance of metal/carbon hybrid multijunction devices, with respect to monolithic carbon device, which is further reduced by decreasing the thickness of carbon layers. We also propose and discuss equivalent circuit model to explain electrical resistance in monolithic carbon and metal/carbon multijunction devices. Cu/carbon multijunction devices display relatively better electrical transport than Ti/carbon devices owing to low affinity of Cu with carbon that restricts carbide formation. We also observe that in metal/carbon multijunction devices, the transport mechanism changes from Poole-Frenkel/Schottky model to the hopping model with a decrease in carbon thickness. Our approach opens a new route to develop carbon-based inexpensive electronic and optoelectronic devices.

  20. Selection of viable cell subpopulations from murine tumours using FACS

    International Nuclear Information System (INIS)

    Chaplin, D.J.; Durand, R.E.; Olive, P.L.

    1985-01-01

    The authors developed a technique which enables isolation of viable tumour cells subpopulation as a function of their distance from the blood supply. The basis for this separation procedure is that the fluorochrome, Hoechst 33342, as a result of its high avidity for cellular DNA, exhibits a marked diffusion/consumption gradient when it has to pass through several cell layers. As a result intravenous injection of Hoechst 33342 into tumour bearing animals, results in a heterogeneous straining pattern within the tumour with cells close to blood vessels being brightly fluorescent while those more distant are less intensely stained. Since these differences in staining intensity persist after tumour disaggregation, cells can be sorted into subpopulations on the basis of their fluorescence intensity using a fluorescence activated cell sorter. This technique offers the unique possibility of identifying the location of those cell subpopulations resistant to treatment with either radiation or chemotherapeutic drugs

  1. Enhanced selection of high affinity DNA-reactive B cells following cyclophosphamide treatment in mice.

    Directory of Open Access Journals (Sweden)

    Daisuke Kawabata

    2010-01-01

    Full Text Available A major goal for the treatment of patients with systemic lupus erythematosus with cytotoxic therapies is the induction of long-term remission. There is, however, a paucity of information concerning the effects of these therapies on the reconstituting B cell repertoire. Since there is recent evidence suggesting that B cell lymphopenia might attenuate negative selection of autoreactive B cells, we elected to investigate the effects of cyclophosphamide on the selection of the re-emerging B cell repertoire in wild type mice and transgenic mice that express the H chain of an anti-DNA antibody. The reconstituting B cell repertoire in wild type mice contained an increased frequency of DNA-reactive B cells; in heavy chain transgenic mice, the reconstituting repertoire was characterized by an increased frequency of mature, high affinity DNA-reactive B cells and the mice expressed increased levels of serum anti-DNA antibodies. This coincided with a significant increase in serum levels of BAFF. Treatment of transgene-expressing mice with a BAFF blocking agent or with DNase to reduce exposure to autoantigen limited the expansion of high affinity DNA-reactive B cells during B cell reconstitution. These studies suggest that during B cell reconstitution, not only is negative selection of high affinity DNA-reactive B cells impaired by increased BAFF, but also that B cells escaping negative selection are positively selected by autoantigen. There are significant implications for therapy.

  2. Urea selectively induces DNA synthesis in renal epithelial cells.

    Science.gov (United States)

    Cohen, D M; Gullans, S R

    1993-04-01

    Hyperosmotic stress with the functionally impermeant solute NaCl has been shown by us and others to inhibit cell growth and DNA synthesis. Several lines of evidence suggest that urea, the other principal renal medullary solute, may exert a growth-promoting effect on renal epithelial cells. Among these is the finding that urea upregulates expression at the mRNA level of two growth-associated immediate-early genes, Egr-1 and c-fos. In the present study, urea, in concentrations characteristic of the renal medulla, increased [3H]thymidine incorporation approximately threefold in confluent, growth-suppressed Madin-Darby canine kidney (MDCK) cells, whereas another readily membrane-permeant solute, glycerol, did not. Urea also overcame the inhibitory effect of hyperosmotic NaCl on DNA synthesis. The urea-induced increase in [3H]thymidine incorporation was also evident in the renal epithelial LLC-PK1 cell line, but not in renal nonepithelial and epithelial nonrenal cell types examined. In addition, it was associated with a 15% increase in total DNA content measured fluorometrically at 24 h of treatment. There was, however, no associated increase in cell proliferation as measured by cell number, total protein content, or cell cycle distribution. Urea also failed to induce polyploidy or aneuploidy. Therefore cells of renal epithelial origin may be uniquely capable of responding to hyperosmotic urea with increased DNA synthesis through an undefined and potentially novel mechanism.

  3. Withaferin A Induces Cell Death Selectively in Androgen-Independent Prostate Cancer Cells but Not in Normal Fibroblast Cells.

    Directory of Open Access Journals (Sweden)

    Yukihiro Nishikawa

    Full Text Available Withaferin A (WA, a major bioactive component of the Indian herb Withania somnifera, induces cell death (apoptosis/necrosis in multiple types of tumor cells, but the molecular mechanism underlying this cytotoxicity remains elusive. We report here that 2 μM WA induced cell death selectively in androgen-insensitive PC-3 and DU-145 prostate adenocarcinoma cells, whereas its toxicity was less severe in androgen-sensitive LNCaP prostate adenocarcinoma cells and normal human fibroblasts (TIG-1 and KD. WA also killed PC-3 cells in spheroid-forming medium. DNA microarray analysis revealed that WA significantly increased mRNA levels of c-Fos and 11 heat-shock proteins (HSPs in PC-3 and DU-145, but not in LNCaP and TIG-1. Western analysis revealed increased expression of c-Fos and reduced expression of the anti-apoptotic protein c-FLIP(L. Expression of HSPs such as HSPA6 and Hsp70 was conspicuously elevated; however, because siRNA-mediated depletion of HSF-1, an HSP-inducing transcription factor, reduced PC-3 cell viability, it is likely that these heat-shock genes were involved in protecting against cell death. Moreover, WA induced generation of reactive oxygen species (ROS in PC-3 and DU-145, but not in normal fibroblasts. Immunocytochemistry and immuno-electron microscopy revealed that WA disrupted the vimentin cytoskeleton, possibly inducing the ROS generation, c-Fos expression and c-FLIP(L suppression. These observations suggest that multiple events followed by disruption of the vimentin cytoskeleton play pivotal roles in WA-mediated cell death.

  4. Modular extracellular sensor architecture for engineering mammalian cell-based devices.

    Science.gov (United States)

    Daringer, Nichole M; Dudek, Rachel M; Schwarz, Kelly A; Leonard, Joshua N

    2014-12-19

    Engineering mammalian cell-based devices that monitor and therapeutically modulate human physiology is a promising and emerging frontier in clinical synthetic biology. However, realizing this vision will require new technologies enabling engineered circuitry to sense and respond to physiologically relevant cues. No existing technology enables an engineered cell to sense exclusively extracellular ligands, including proteins and pathogens, without relying upon native cellular receptors or signal transduction pathways that may be subject to crosstalk with native cellular components. To address this need, we here report a technology we term a Modular Extracellular Sensor Architecture (MESA). This self-contained receptor and signal transduction platform is maximally orthogonal to native cellular processes and comprises independent, tunable protein modules that enable performance optimization and straightforward engineering of novel MESA that recognize novel ligands. We demonstrate ligand-inducible activation of MESA signaling, optimization of receptor performance using design-based approaches, and generation of MESA biosensors that produce outputs in the form of either transcriptional regulation or transcription-independent reconstitution of enzymatic activity. This systematic, quantitative platform characterization provides a framework for engineering MESA to recognize novel ligands and for integrating these sensors into diverse mammalian synthetic biology applications.

  5. Resource Competition Determines Selection of B Cell Repertoires

    NARCIS (Netherlands)

    Boer, R.J. de; Freitas, A.A. (António); Perelson, A.S. (Alan)

    2001-01-01

    Previous experiments with mouse chimeras demonstrated that cellular competition for antigen- specific survival signals plays a crucial role in the maintenance of the naive B cell repertoire. Transgenic (Tg) B cell populations in these chimeras have a shortened lifespan and poor competitive

  6. Ventricular assist device implantation in the pediatric population: does pump size selection and associated hemodynamics impact outcomes?

    Science.gov (United States)

    Husain, S Adil; Wallis, Gonzolo; Fricker, Fredrick J; Bleiweis, Mark S; Staples, Edward D; Klodell, Charles T; Brown, John W; Turrentine, Mark W

    2008-01-01

    The use of pediatric ventricular assist devices (VADs) continues to evolve with the availability of smaller blood pumps. We examine the correlation of implanting appropriate sized blood pumps with a lower incidence of VAD related complications (VADRC). A 7-year retrospective review was undertaken for all pediatric VAD patients. Optimal VAD hemodynamics were defined as cardiac index of 2.7 L/m2 and rate of 80 beats per minute (bpm) with complete fill/empty of the blood pump. Patient/blood pump size match, VAD rate and fill/empty ratios were calculated (optimum = 1.0) and then correlated with incidence of VADRC. The study included 22 patients, mean age 9.77 years (6 mo-18 yrs) and mean body surface area (BSA) of 1.14 m2 (0.14 m2-2.32 m2), who underwent VAD implantation. VADRC included death while on support (n = 5), bleeding requiring reoperation (n = 8), hemolysis (n = 2), neurologic events (n = 2), thrombus formation (n = 3), and infection (n = 3). Six patients were bridged to transplant without any VADRC. This subset of patients had a mean blood pump size match ratio of 0.98, VAD rate ratio of 0.92 and fill/empty ratio of 1.00. Patients with VADRC (n = 16) were found to have a mean blood pump size match ratio of 0.72, VAD rate ratio of 0.72 and fill/empty ratio of 0.78. We report a series of pediatric patients with wide ranging BSA receiving VAD implantation. Selection of appropriate sized blood pumps can be correlated with decreased VADRC.

  7. Selection and physiology of cell cultures of Douglas-fir grown under conditions of water stress.

    Science.gov (United States)

    Leustek, T; Kirby, E G

    1990-09-01

    Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) cell cultures sampled 3, 6, or 9 days after subculture in nutrient medium were able to survive subsequent subculture in a medium containing 15% polyethylene glycol (PEG) (M(r) 6000-8000) (-1.21 MPa), whereas cell sampled 12 or 16 days after subculture in nutrient medium became senescent when transferred to a medium containing 15% PEG. Cells sampled after subculture for 3, 6, or 9 days in nutrient medium had lower fresh weight/dry weight ratios, lower osmotic potentials, smaller cell diameters, and higher turgor pressures than cells sampled after 12 or 16 days subculture in nutrient medium. Cells surviving subculture to a medium containing 15% PEG did not increase in dry weight for 5 weeks even though the medium was exchanged every 7 days. After 5 weeks, however, dry weight growth resumed and reached 75% of the level attained by control cells grown on PEG-free medium. Long-term growth on a medium containing 15% PEG (PEG-selected cells) could only be sustained if the medium was supplemented with 30 mM glutamine. The PEG-selected cells grew in small clusters, were isodiametric, and had chlorophyll contents 50% higher than unselected cells. The PEG-selected cells also showed lowered cellular osmotic potentials, presumably due to osmoregulation. Turgor pressures of PEG-selected cells were greater than or equal to those of unselected cells.

  8. Device, Interface, Process and Electrode Engineering Towards Low Cost and High Efficiency Polymer Solar Cells in Inverted Structure

    Science.gov (United States)

    Zou, Jingyu

    As a promising technology for economically viable alternative energy source, polymer solar cells (PSCs) have attracted substantial interests and made significant progress in the past few years, due the advantages of being potentially easily solution processed into large areas, flexible, light weight, and have the versatility of material design. In this dissertation, an integrated approach is taken to improve the overall performance of polymer solar cells by the development of new polymer materials, device architectures, interface engineering of the contacts between layers, and new transparent electrodes. First, several new classes of polymers are explored as potential light harvesting materials for solar cells. Processing has been optimized and efficiency as high as 6.24% has been demonstrated. Then, with the development of inverted device structure, which has better air stability by utilizing more air stable, high work function metals, newly developed high efficiency polymers have been integrated into inverted structure device with integrated engineering approach. A comprehensive characterization and optical modeling based on conventional and inverted devices have been performed to understand the effect of device geometry on photovoltaic performance based on a newly developed high performance polymer poly(indacenodithiophene-co-phananthrene-quinoxaline) (PIDT-PhanQ). By modifying anode with a bilayer combining graphene oxide (GO) and poly(3,4-ethylenedioxylenethiophene):poly(styrenesulfonic acid) (PEDOT:PSS) as hole transporter/electron blocker, it further improved device performance of inverted structured to 6.38%. A novel processing method of sequentially bilayer deposition for active layer has been conducted based on a low band-gap polymer poly[2, 6-(4, 4-bis-(2-ethylhexyl)-4 H-cyclopenta [2,1-b;3,4-b‧] dithiophene)- alt-4,7-(2, 1, 3- fluorobenzothiadiazole)] (PCPDT-FBT). Inverted structure devices processed from bilayer deposition shows even higher

  9. Comparison of Cold Atmospheric Plasma Devices' Efficacy on Osteosarcoma and FibroblasticIn VitroCell Models.

    Science.gov (United States)

    Gümbel, Denis; Suchy, Bettina; Wien, Lasse; Gelbrich, Nadine; Napp, Matthias; Kramer, Axel; Ekkernkamp, Axel; Daeschlein, Georg; Stope, Matthias B

    2017-10-01

    Cold atmospheric plasma (CAP) attenuates tumor cell proliferation and induces apoptosis in various cell lines. While exerting marginal effects on non-neoplastic cells this unfolds promising applications in cancer therapy. The aim of the study was to analyse the effects of different CAP sources and application times on osteosarcoma (OS) cells and non-malignant fibroblast cell proliferation. U2-OS and 3-T-3 fibroblasts were treated with three different approved medical devices. Carrier gas-treated cells served as controls. Cell proliferation was determined by viable cell count at different time points after treatment. Control exposed U2-OS and 3-T-3 cells exhibited characteristic cell growth. CAP application of U2-OS and 3-T-3 cells attenuated proliferation rates up to 98%. Attenuation rates varied between cell lines, plasma sources and application times. CAP treatment attenuates cell proliferation of OS cancer cells and fibroblasts in a treatment time-dependent manner, whereby U2-OS cells appeared more sensitive to CAP treatment as 3T3 fibroblasts after 10 sec of treatment. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

  10. Magnesium-doped Zinc Oxide as Electron Selective Contact Layers for Efficient Perovskite Solar Cells.

    Science.gov (United States)

    Song, Jiaxing; Zheng, Enqiang; Liu, Leijing; Wang, Xiao-Feng; Chen, Gang; Tian, Wenjing; Miyasaka, Tsutomu

    2016-09-22

    The electron-selective contact layer (ESL) in organometal halide-based perovskite solar cells (PSCs) determines not only the power conversion efficiency (PCE) but also the thermostability of PSCs. To improve the thermostability of ZnO-based PSCs, we developed Mg-doped ZnO [Zn 1-x Mg x O (ZMO)] as a high optical transmittance ESL for the methylammonium lead trihalide perovskite absorber [CH 3 NH 3 PbI 3 ]. We further investigated the optical and electrical properties of the ESL films with Mg contents of 0-30 mol % and the corresponding devices. We achieved a maximum PCE of 16.5 % with improved thermal stability of CH 3 NH 3 PbI 3 on ESL with the optimal ZMO (0.4 m) containing 10 mol % Mg. Moreover, this optimized ZMO PSC exhibited significantly improved durability and photostability owing to the improved chemical/photochemical stability of the wider optical bandgap ZMO. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Toward Wearable Energy Storage Devices: Paper-Based Biofuel Cells based on a Screen-Printing Array Structure.

    Science.gov (United States)

    Shitanda, Isao; Momiyama, Misaki; Watanabe, Naoto; Tanaka, Tomohiro; Tsujimura, Seiya; Hoshi, Yoshinao; Itagaki, Masayuki

    2017-10-01

    A novel paper-based biofuel cell with a series/parallel array structure has been fabricated, in which the cell voltage and output power can easily be adjusted as required by printing. The output of the fabricated 4-series/4-parallel biofuel cell reached 0.97±0.02 mW at 1.4 V, which is the highest output power reported to date for a paper-based biofuel cell. This work contributes to the development of flexible, wearable energy storage device.

  12. Scanning electroporation of selected areas of adherent cell cultures.

    Science.gov (United States)

    Olofsson, Jessica; Levin, Mikael; Strömberg, Anette; Weber, Stephen G; Ryttsén, Frida; Orwar, Owe

    2007-06-15

    We present a computer-controlled scanning electroporation method. Adherent cells are electroporated using an electrolyte-filled capillary in contact with an electrode. The capillary can be scanned over a cell culture and locally deliver both an electric field and an electroporation agent to the target area without affecting surrounding cells. The instantaneous size of the targeted area is determined by the dimensions of the capillary. The size and shape of the total electroporated area are defined by these dimensions in combination with the scanning pattern. For example, striped and serpentine patterns of electroporated cells in confluent cultures can be formed. As it is easy to switch between different electroporation agents, the method is suitable for design of cell cultures with complex composition. Finite element method simulations were used to study the spatial distributions of the electric field and the concentration of an electroporation agent, as well as the fluid dynamics related to scanning and flow of electroporation agent from the capillary. The method was validated for transfection by introduction of a 9-base-pair-long randomized oligonucleotide into PC12 cells and a pmaxGFP plasmid coding for green fluorescent protein into CHO and WSS cells.

  13. Biogrid--a microfluidic device for large-scale enzyme-free dissociation of stem cell aggregates.

    Science.gov (United States)

    Wallman, Lars; Åkesson, Elisabet; Ceric, Dario; Andersson, Per Henrik; Day, Kelly; Hovatta, Outi; Falci, Scott; Laurell, Thomas; Sundström, Erik

    2011-10-07

    Culturing stem cells as free-floating aggregates in suspension facilitates large-scale production of cells in closed systems, for clinical use. To comply with GMP standards, the use of substances such as proteolytic enzymes should be avoided. Instead of enzymatic dissociation, the growing cell aggregates may be mechanically cut at passage, but available methods are not compatible with large-scale cell production and hence translation into the clinic becomes a severe bottle-neck. We have developed the Biogrid device, which consists of an array of micrometerscale knife edges, micro-fabricated in silicon, and a manifold in which the microgrid is placed across the central fluid channel. By connecting one side of the Biogrid to a syringe or a pump and the other side to the cell culture, the culture medium with suspended cell aggregates can be aspirated, forcing the aggregates through the microgrid, and ejected back to the cell culture container. Large aggregates are thereby dissociated into smaller fragments while small aggregates pass through the microgrid unaffected. As proof-of-concept, we demonstrate that the Biogrid device can be successfully used for repeated passage of human neural stem/progenitor cells cultured as so-called neurospheres, as well as for passage of suspension cultures of human embryonic stem cells. We also show that human neural stem/progenitor cells tolerate transient pressure changes far exceeding those that will occur in a fluidic system incorporating the Biogrid microgrids. Thus, by using the Biogrid device it is possible to mechanically passage large quantities of cells in suspension cultures in closed fluidic systems, without the use of proteolytic enzymes.

  14. High affinity nanobodies against human epidermal growth factor receptor selected on cells by E. coli display

    NARCIS (Netherlands)

    Salema, Valencio; Mañas, Carmen; Cerdán, Lidia; Piñero-Lambea, Carlos; Marín, Elvira; Roovers, Rob C.|info:eu-repo/dai/nl/205435599; Van Bergen en Henegouwen, Paul M P|info:eu-repo/dai/nl/071919481; Fernández, Luis Ángel

    2016-01-01

    Most therapeutic antibodies (Abs) target cell surface proteins on tumor and immune cells. Cloning of Ab gene libraries in E. coli and their display on bacteriophages is commonly used to select novel therapeutic Abs binding target antigens, either purified or expressed on cells. However, the sticky

  15. Double suicide genes selectively kill human umbilical vein endothelial cells

    Directory of Open Access Journals (Sweden)

    Liu Lunxu

    2011-02-01

    Full Text Available Abstract Background To construct a recombinant adenovirus containing CDglyTK double suicide genes and evaluate the killing effect of the double suicide genes driven by kinase domain insert containing receptor (KDR promoter on human umbilical vein endothelial cells. Methods Human KDR promoter, Escherichia coli (E. coli cytosine deaminase (CD gene and the herpes simplex virus-thymidine kinase (TK gene were cloned using polymerase chain reaction (PCR. Plasmid pKDR-CDglyTK was constructed with the KDR promoter and CDglyTK genes. A recombinant adenoviral plasmid AdKDR-CDglyTK was then constructed and transfected into 293 packaging cells to grow and harvest adenoviruses. KDR-expressing human umbilical vein endothelial cells (ECV304 and KDR-negative liver cancer cell line (HepG2 were infected with the recombinant adenoviruses at different multiplicity of infection (MOI. The infection rate was measured by green fluorescent protein (GFP expression. The infected cells were cultured in culture media containing different concentrations of prodrugs ganciclovir (GCV and/or 5-fluorocytosine (5-FC. The killing effects were measured using two different methods, i.e. annexin V-FITC staining and terminal transferase-mediated dUTP nick end-labeling (TUNEL staining. Results Recombinant adenoviruses AdKDR-CDglyTK were successfully constructed and they infected ECV304 and HepG2 cells efficiently. The infection rate was dependent on MOI of recombinant adenoviruses. ECV304 cells infected with AdKDR-CDglyTK were highly sensitive to GCV and 5-FC. The cell survival rate was dependent on both the concentration of the prodrugs and the MOI of recombinant adenoviruses. In contrast, there were no killing effects in the HepG2 cells. The combination of two prodrugs was much more effective in killing ECV304 cells than GCV or 5-FC alone. The growth of transgenic ECV304 cells was suppressed in the presence of prodrugs. Conclusion AdKDR-CDglyTK/double prodrog system may be a useful

  16. High-throughput deterministic single-cell encapsulation and droplet pairing, fusion, and shrinkage in a single microfluidic device.

    Science.gov (United States)

    Schoeman, Rogier M; Kemna, Evelien W M; Wolbers, Floor; van den Berg, Albert

    2014-02-01

    In this article, we present a microfluidic device capable of successive high-yield single-cell encapsulation in droplets, with additional droplet pairing, fusion, and shrinkage. Deterministic single-cell encapsulation is realized using Dean-coupled inertial ordering of cells in a Yin-Yang-shaped curved microchannel using a double T-junction, with a frequency over 2000 Hz, followed by controlled droplet pairing with a 100% success rate. Subsequently, droplet fusion is realized using electrical actuation resulting in electro-coalescence of two droplets, each containing a single HL60 cell, with 95% efficiency. Finally, volume reduction of the fused droplet up to 75% is achieved by a triple pitchfork structure. This droplet volume reduction is necessary to obtain close cell-cell membrane contact necessary for final cell electrofusion, leading to hybridoma formation, which is the ultimate aim of this research. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Effect of copper intrauterine device vs. injectable contraceptive on serum hormone levels and cell mitotic activity in endometrium

    Directory of Open Access Journals (Sweden)

    Ebtesam Moustafa Kamal

    2013-09-01

    Conclusion: Either copper intrauterine device or injectable contraceptive usage for more than 9 months results in significant decrease in endometrial proliferative or cell mitotic activity. While copper IUD has no effect on serum estradiol or progesterone levels, DMPA usage increased serum progesterone level with no effect on serum estradiol.

  18. Effects of Cell-Saving Devices and Filters on Transfusion in Cardiac Surgery : A Multicenter Randomized Study

    NARCIS (Netherlands)

    Vermeijden, Wytze J.; van Klarenbosch, Jan; Gu, Y. John; Mariani, Massimo A.; Buhre, Wolfgang F.; Scheeren, Thomas W. L.; Hagenaars, Johanna A. M.; Tan, M. Erwin S. H.; Haenen, Jo S. E.; Bras, Leo; van Oeveren, Wim; van den Heuvel, Edwin R.; de Vries, Adrianus J.

    Background: Cell-saving devices (CS) are frequently used in cardiac surgery to reduce transfusion requirements, but convincing evidence from randomized clinical trials is missing. Filtration of salvaged blood in combination with the CS is widely used to improve the quality of retransfused blood, but

  19. Effects of cell-saving devices and filters on transfusion in cardiac surgery : a multicenter randomized study

    NARCIS (Netherlands)

    Vermeijden, Wytze J; van Klarenbosch, Jan; Gu, Y John; Mariani, Massimo A; Buhre, Wolfgang F; Scheeren, Thomas W L; Hagenaars, Johanna A M; Tan, M Erwin S H; Haenen, Jo S E; Bras, Leo; van Oeveren, Wim; van den Heuvel, Edwin R; de Vries, Adrianus J

    BACKGROUND: Cell-saving devices (CS) are frequently used in cardiac surgery to reduce transfusion requirements, but convincing evidence from randomized clinical trials is missing. Filtration of salvaged blood in combination with the CS is widely used to improve the quality of retransfused blood, but

  20. Device Strategies Directed to Improving the Efficiency of Solution-Processed Organic Solar Cells

    KAUST Repository

    Liang, Ru-Ze

    2018-04-18

    In the last decade, organic photovoltaics (OPVs) have been attracting much attention for their low cost, and feasibility of mass production in large-area modules. Reported power conversion efficiencies (PCE) of organic solar cells have reached more than 10%. These promising PCEs can be realized by uncovering important principles: (1) rational molecular design, (2) matching of the material energy level, (3) favorable morphology of donor-acceptor (D/A) network, (4) higher carrier mobilities, and (5) suppression of charge recombination within the bulk heterojunction (BHJ). Though these key properties are frequently stated, the relationships between these principles remain unclear, which motivates us to fill these gaps. In the beginning, we show that changing the sequence of donor and acceptor units of the benzodithiophene-core (BDT) SM donors critically impacts molecular packing and charge transport in BHJ solar cells. Moreover, we find out that by adding small amount of the external solvent additive, the domain size of the SMFQ1 become relatively smaller, resulting in the FF enhancement of ~70% and thus pushing PCE to >6.5%. To further improve the device performance, we utilize another technique of device optimization: Solvent Vapor Annealing (SVA). Compared with solvent additive, the SVA creates a solvent-saturated environment for SMs to re-arrange and crystalize, leading to PCE of >8%, with nearly-free bimolecular recombination. When the systems are shifted from fullerene acceptors to nonfullerene acceptors, using solvent additives in indacenodithiophene-core (IDT) systems significantly reduces the domain size from >500nm to <50nm and also allows the SM donors to orderly packed, rising the PCE from <1% to 4.5%. Furthermore in a similar IDT-based system, it shows unexpectedly high VOC and low energy loss, and high PCE > 6% can be reached by employing the dimethyl disulfide (DMDS) as the SVA solvent to re-organize the morphology from excessive mixing to ordered phase

  1. Functional Beta Cell Mass from Device-Encapsulated hESC-Derived Pancreatic Endoderm Achieving Metabolic Control

    Directory of Open Access Journals (Sweden)

    Thomas Robert

    2018-03-01

    Full Text Available Summary: Human stem cells represent a potential source for implants that replace the depleted functional beta cell mass (FBM in diabetes patients. Human embryonic stem cell-derived pancreatic endoderm (hES-PE can generate implants with glucose-responsive beta cells capable of reducing hyperglycemia in mice. This study with device-encapsulated hES-PE (4 × 106 cells/mouse determines the biologic characteristics at which implants establish metabolic control during a 50-week follow-up. A metabolically adequate FBM was achieved by (1 formation of a sufficient beta cell number (>0.3 × 106/mouse at >50% endocrine purity and (2 their maturation to a functional state comparable with human pancreatic beta cells, as judged by their secretory responses during perifusion, their content in typical secretory vesicles, and their nuclear NKX6.1-PDX1-MAFA co-expression. Assessment of FBM in implants and its correlation with in vivo metabolic markers will guide clinical translation of stem cell-derived grafts in diabetes. : In this article, Pipeleers and colleagues demonstrate that subcutaneous implants of device-encapsulated human stem cell-derived pancreatic endoderm can generate a functional beta cell mass that establishes sustained glucose control in mice. They identified their biologic characteristics and correlation with in vivo outcome. Data and methods are expected to guide clinical translation to beta cell replacement therapy in diabetes. Keywords: stem cell-derived pancreatic endoderm, stem cell therapy, diabetes, encapsulation, differentiation, functional maturation, functional beta cell mass, metabolic control

  2. CARbodies: Human Antibodies Against Cell Surface Tumor Antigens Selected From Repertoires Displayed on T Cell Chimeric Antigen Receptors

    Directory of Open Access Journals (Sweden)

    Vanesa Alonso-Camino

    2013-01-01

    Full Text Available A human single-chain variable fragment (scFv antibody library was expressed on the surface of human T cells after transduction with lentiviral vectors (LVs. The repertoire was fused to a first-generation T cell receptor ζ (TCRζ-based chimeric antigen receptor (CAR. We used this library to isolate antibodies termed CARbodies that recognize antigens expressed on the tumor cell surface in a proof-of-principle system. After three rounds of activation-selection there was a clear repertoire restriction, with the emergence dominant clones. The CARbodies were purified from bacterial cultures as soluble and active proteins. Furthermore, to validate its potential application for adoptive cell therapy, human T cells were transduced with a LV encoding a second-generation costimulatory CAR (CARv2 bearing the selected CARbodies. Transduced human primary T cells expressed significant levels of the CARbodies-based CARv2 fusion protein on the cell surface, and importantly could be specifically activated, after stimulation with tumor cells. This approach is a promising tool for the generation of antibodies fully adapted to the display format (CAR and the selection context (cell synapse, which could extend the scope of current adoptive cell therapy strategies with CAR-redirected T cells.

  3. Next Generation Solar Cells Based on Graded Bandgap Device Structures Utilising Rod-Type Nano-Materials

    Directory of Open Access Journals (Sweden)

    Imyhamy M. Dharmadasa

    2015-06-01

    Full Text Available Current solar cells under research and development utilise mainly one absorber layer limiting the photon harvesting capabilities. In order to develop next generation solar cells, research should move towards effective photon harvesting methods utilising low-cost solar energy materials. This will lead to reduce the $W−1 figure for direct solar energy conversion to electrical energy. In this work, a graded bandgap solar cell has been designed to absorb all photons from the UV, visible and IR regions. In addition, impurity PV effect and impact ionisation have been incorporated to enhance charge carrier creation within the same device. This new design has been experimentally tested using the most researched MOCVD grown GaAs/AlGaAs system, in order to confirm its validity. Devices with high Voc ~ 1175 mV and the highest possible FF ~ (0.85–0.87 have been produced, increasing the conversion efficiency to ~20% within only two growth runs. These devices were also experimentally tested for the existence of impurity PV effect and impact ionisation. The devices are PV active in complete darkness producing over 800 mV, Voc indicating the harvesting of IR radiation from the surroundings through impurity PV effect. The quantum efficiency measurements show over 140% signal confirming the contribution to PV action from impact ionisation. Since the concept is successfully proven, the low-cost and scalable electrodeposited semiconducting layers are used to produce graded bandgap solar cell structures. The utilisation of nano- and micro-rod type materials in graded bandgap devices are also presented and discussed in this paper. Preliminary work on glass/FTO/n-ZnS/n-CdS/n-CdTe/Au graded bandgap devices show 10%–12% efficient devices indicating extremely high Jsc values ~48 mA·cm−2, showing the high potential of these devices in achieving higher efficiencies. The detailed results on these low-cost and novel graded bandgap devices are presented in a separate

  4. Selectivity of biopolymer membranes using HepG2 cells.

    Science.gov (United States)

    Lü, Dongyuan; Gao, Yuxin; Luo, Chunhua; Lü, Shouqian; Wang, Qian; Xu, Xianghong; Sun, Shujin; Wang, Chengzhi; Long, Mian

    2015-03-01

    Bioartificial liver (BAL) system has emerged as an alternative treatment to bridge acute liver failure to either liver transplantation or liver regeneration. One of the main reasons that the efficacy of the current BAL systems was not convincing in clinical trials is attributed to the lack of friendly interface between the membrane and the hepatocytes in liver bioreactor, the core unit of BAL system. Here, we systematically compared the biological responses of hepatosarcoma HepG2 cells seeded on eight, commercially available biocompatible membranes made of acetyl cellulose-nitrocellulose mixed cellulose (CA-NC), acetyl cellulose (CA), nylon (JN), polypropylene (PP), nitrocellulose (NC), polyvinylidene fluoride (PVDF), polycarbonate (PC) and polytetrafluoroethylene (PTFE). Physicochemical analysis and mechanical tests indicated that CA, JN and PP membranes yield high adhesivity and reasonable compressive and/or tensile features with friendly surface topography for cell seeding. Cells prefer to adhere on CA, JN, PP or PTFE membranes with high proliferation rate in spheriod-like shape. Actin, albumin and cytokeratin 18 expressions are favorable for cells on CA or PP membrane, whereas protein filtration is consistent among all the eight membranes. These results further the understandings of cell growth, morphology and spreading, as well as protein filtration on distinct membranes in designing a liver bioreactor.

  5. HSP90 inhibitor 17-AAG selectively eradicates lymphoma stem cells.

    Science.gov (United States)

    Newman, Bryan; Liu, Yan; Lee, Hsiu-Fang; Sun, Duxin; Wang, Yin

    2012-09-01

    Cancer stem cells (CSC; also called tumor-initiating cells) comprise tumor cell subpopulations that preserve the properties of quiescence, self-renewal, and differentiation of normal stem cells. In addition, CSCs are therapeutically important because of their key contributions toward drug resistance. The hypoxia-inducible transcription factor HIF1α is critical for CSC maintenance in mouse lymphoma. In this study, we showed that low concentrations of the HSP90 inhibitor 17-AAG eliminate lymphoma CSCs in vitro and in vivo by disrupting the transcriptional function of HIF1α, a client protein of HSP90. 17-AAG preferentially induced apoptosis and eliminated the colony formation capacity of mouse lymphoma CSCs and human acute myeloid leukemia (AML) CSCs. However, low concentrations of 17-AAG failed to eliminate highly proliferative lymphoma and AML cells (non-CSCs), in which the AKT-GSK3 signaling pathway is constitutively active. The heat shock transcription factor HSF1 is highly expressed in non-CSCs, but it was weakly expressed in lymphoma CSCs. However, siRNA-mediated attenuation of HSF1 abrogated the colony formation ability of both lymphoma and AML CSCs. This study supports the use of 17-AAG as a CSC targeting agent and, in addition, shows that HSF1 is an important target for elimination of both CSCs and non-CSCs in cancer. ©2012 AACR.

  6. Structure-activity relationship of 9-methylstreptimidone, a compound that induces apoptosis selectively in adult T-cell leukemia cells.

    Science.gov (United States)

    Takeiri, Masatoshi; Ota, Eisuke; Nishiyama, Shigeru; Kiyota, Hiromasa; Umezawa, Kazuo

    2012-01-01

    We previously reported that 9-methylstreptimidone, a piperidine compound isolated from a culture filtrate of Streptomyces, induces apoptosis selectively in adult T-cell leukemia cells. It was screened for a compound that inhibits LPS-induced NF-kappaB and NO production in mouse macrophages. However, 9-methystreptimidone is poorly obtained from the producing microorganism and difficult to synthesize. Therefore, in the present research, we studied the structure-activity relationship to look for new selective inhibitors. We found that the structure of the unsaturated hydrophobic portion of 9-methylstreptimidone was essential for the inhibition of LPS-induced NO production. Among the 9-methylstreptimidone-related compounds tested, (+/-)-4,alpha-diepi-streptovitacin A inhibited NO production in macrophage-like cells as potently as 9-methylstreptimidone and without cellular toxicity. Moreover, this compound selectively induced apoptosis in adult T-cell leukemia MT-1 cells.

  7. Properties of pattern and component direction-selective cells in area MT of the macaque

    Science.gov (United States)

    Wang, Helena X.

    2015-01-01

    Neurons in area MT/V5 of the macaque visual cortex encode visual motion. Some cells are selective for the motion of oriented features (component direction-selective, CDS); others respond to the true direction of complex patterns (pattern-direction selective, PDS). There is a continuum of selectivity in MT, with CDS cells at one extreme and PDS cells at the other; we compute a pattern index that captures this variation. It is unknown how a neuron's pattern index is related to its other tuning characteristics. We therefore analyzed the responses of 792 MT cells recorded in the course of other experiments from opiate-anesthetized macaque monkeys, as a function of the direction, spatial frequency, drift rate, size, and contrast of sinusoidal gratings and of the direction and speed of random-dot textures. We also compared MT responses to those of 718 V1 cells. As expected, MT cells with higher pattern index tended to have stronger direction selectivity and broader direction tuning to gratings, and they responded better to plaids than to gratings. Strongly PDS cells also tended to have smaller receptive fields and stronger surround suppression. Interestingly, they also responded preferentially to higher drift rates and higher speeds of moving dots. The spatial frequency preferences of PDS cells depended strongly on their preferred temporal frequencies, whereas these preferences were independent in component-selective cells. Pattern direction selectivity is statistically associated with many response properties of MT cells but not strongly associated with any particular property. Pattern-selective signals are thus available in association with most other signals exported by MT. PMID:26561603

  8. Cytotoxicity of Selected Nanoparticles on Human Dental Pulp Stem Cells.

    Science.gov (United States)

    Tabari, Kasra; Hosseinpour, Sepanta; Parashos, Peter; Kardouni Khozestani, Parisa; Rahimi, Hossein Mohammad

    2017-01-01

    Nanoparticles are being increasingly applied in dentistry due to their antimicrobial and mechanical properties. This in vitro study aimed to assess and compare the cytotoxicity of four metal oxide nanoparticles (TiO 2 , SiO 2 , ZnO, and Al 2 O 3 ) on human dental pulp stem cells. Four suspension with different concentrations (25, 50, 75, 100 µg/mL) of each nanoparticle were prepared and placed into cavities of three 96-well plates (containing 1×10 4 cells per well that were seeded 24 earlier). All specimens were incubated in a humidified incubator with 5% CO 2 at 37 ° C. Mosmann's Tetrazolium Toxicity (MTT) assay was used to determine in vitro cytotoxicity of test materials on pulpal stem cells. Cell viability was determined at 24, 48, and 72 h after exposure. Data comparisons were performed using a general linear model for repeated measures and Tukey's post hoc test. The level of significance was set at 0.05. The tested nanoparticles showed variable levels of cytotoxicity and were dose and time dependant. The minimum cell viability was observed in ZnO followed by TiO 2 , SiO 2 and Al 2 O 3 . The results demonstrated that cell viability and morphological modifications occurred at the concentration range of 25 to 100 µg/mL and in all nanoparticles. The higher concentration and longer duration of exposure increased cellular death. Our results highlight the need for a more discrete use of nanoparticles for biomedical applications.

  9. Device and Method for Continuously Equalizing the Charge State of Lithium Ion Battery Cells

    Science.gov (United States)

    Schwartz, Paul D. (Inventor); Martin, Mark N. (Inventor); Roufberg, Lewis M. (Inventor)

    2015-01-01

    A method of equalizing charge states of individual cells in a battery includes measuring a previous cell voltage for each cell, measuring a previous shunt current for each cell, calculating, based on the previous cell voltage and the previous shunt current, an adjusted cell voltage for each cell, determining a lowest adjusted cell voltage from among the calculated adjusted cell voltages, and calculating a new shunt current for each cell.

  10. A microbial fuel cell as power supply for implantable medical devices.

    Science.gov (United States)

    Han, Yufeng; Yu, Chaoling; Liu, Hong

    2010-05-15

    This study seeks a new way to provide lasting and secure power for implantable medical devices (IMDs) using a microbial fuel cell (MFC) which was proposed to be placed in human large intestine and could utilize intestinal contents and microorganisms to generate electricity. Based on the anatomic structure and inner environmental conditions of large intestine, transverse colon was chosen to be the appropriate location for the implantation of MFC. The performance of the MFC which simulated the environmental features of transverse colon by controlling dissolved oxygen (DO) and pH and was inoculated with simulated intestinal fluid (SIF) was investigated. Stable power generation of MFC was obtained after two months operation with open circuit voltage (OCV) of 552.2 mV, maximum power density of 73.3 mW/m(2), and average voltage output of 308 mV (with external resistance of 500 Omega). Moreover, the changes of environmental conditions in the chambers of MFC did not have a significant impact on human body based on the analysis of pH and DO values. Further studies on internal resistance and power density showed that the MFC could generate power of 7-10 mW according to the size of intestinal surface area, which was enough for IMDs. These results suggested that MFCs located in large intestine could be a promising power source for IMDs. 2010 Elsevier B.V. All rights reserved.

  11. From Extended Nanofluidics to an Autonomous Solar-Light-Driven Micro Fuel-Cell Device.

    Science.gov (United States)

    Pihosh, Yuriy; Uemura, Jin; Turkevych, Ivan; Mawatari, Kazuma; Kazoe, Yutaka; Smirnova, Adelina; Kitamori, Takehiko

    2017-07-03

    Autonomous micro/nano mechanical, chemical, and biomedical sensors require persistent power sources scaled to their size. Realization of autonomous micro-power sources is a challenging task, as it requires combination of wireless energy supply, conversion, storage, and delivery to the sensor. Herein, we realized a solar-light-driven power source that consists of a micro fuel cell (μFC) and a photocatalytic micro fuel generator (μFG) integrated on a single microfluidic chip. The μFG produces hydrogen by photocatalytic water splitting under solar light. The hydrogen fuel is then consumed by the μFC to generate electricity. Importantly, the by-product water returns back to the photocatalytic μFG via recirculation loop without losses. Both devices rely on novel phenomena in extended-nano-fluidic channels that ensure ultra-fast proton transport. As a proof of concept, we demonstrate that μFG/μFC source achieves remarkable energy density of ca. 17.2 mWh cm -2 at room temperature. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Continuation of a Levonorgestrel Intrauterine Device During Hematopoietic Stem Cell Transplant: A Case Report.

    Science.gov (United States)

    Brady, Paula C; Soiffer, Robert J; Ginsburg, Elizabeth S

    2017-04-01

    During treatment of hematologic malignancies in premenopausal women, both menstrual suppression and contraception are crucial. Continuation of hormonal intrauterine devices (IUDs) - widely used and highly effective contraceptives that also decrease menstrual flow - is controversial during hematopoietic stem cell transplants (SCTs) due to infectious and vaginal bleeding concerns. A 23-year-old nulligravid female was diagnosed with acute myeloid leukemia (AML, positive for FLT3-ITD, DNMT3A and RUNX1, with normal cytogenetics). She elected to retain her existing levonorgestrel-containing IUD during chemotherapy and SCT. During and following treatment, she remained amenorrheic without infection, despite severe neutropenia and thrombocytopenia. Eight months later, she remains in remission without IUD-related complications. This is the first report of levonorgestrel IUD retention during hematopoietic SCT. Despite severe neutropenia and thrombocytopenia, the patient developed neither pelvic infection by retaining her IUD nor significant vaginal bleeding. Future studies are needed to confirm the safety of levonorgestrel IUDs in women undergoing SCT. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

  13. Paper-Based Analytical Devices Relying on Visible-Light-Enhanced Glucose/Air Biofuel Cells.

    Science.gov (United States)

    Wu, Kaiqing; Zhang, Yan; Wang, Yanhu; Ge, Shenguang; Yan, Mei; Yu, Jinghua; Song, Xianrang

    2015-11-04

    A strategy that combines visible-light-enhanced biofuel cells (BFCs) and electrochemical immunosensor into paper-based analytical devices was proposed for sensitive detection of the carbohydrate antigen 15-3 (CA15-3). The gold nanoparticle modified paper electrode with large surface area and good conductibility was applied as an effective matrix for primary antibodies. The glucose dehydrogenase (GDH) modified gold-silver bimetallic nanoparticles were used as bioanodic biocatalyst and signal magnification label. Poly(terthiophene) (pTTh), a photoresponsive conducting polymer, served as catalyst in cathode for the reduction of oxygen upon illumination by visible light. In the bioanode, electrons were generated through the oxidation of glucose catalyzed by GDH. The amount of electrons is determined by the amount of GDH, which finally depended on the amount of CA15-3. In the cathode, electrons from the bioanode could combine with the generated holes in the HOMO energy level of cathode catalysts pTTh. Meanwhile, the high energy level photoexcited electrons were generated in the LUMO energy level and involved in the oxygen reduction reaction, finally resulting in an increasing current and a decreasing overpotential. According to the current signal, simple and efficient detection of CA15-3 was achieved.

  14. Optimization of processing and modeling issues for thin film solar cell devices: Final report, February 3, 1997--September 1, 1998

    Energy Technology Data Exchange (ETDEWEB)

    Birkmire, R. W.; Phillips, J. E.; Shafarman, W. N.; Hegedus, S. S.; McCandless, B. E.

    2000-02-28

    This final report describes results achieved under a 20-month NREL subcontract to develop and understand thin-film solar cell technology associated to CuInSe{sub 2} and related alloys, a-Si and its alloys, and CdTe. Modules based on all these thin films are promising candidates to meet DOE's long-range efficiency, reliability and manufacturing cost goals. The critical issues being addressed under this program are intended to provide the science and engineering basis for the development of viable commercial processes and to improve module performance. The generic research issues addressed are: (1) quantitative analysis of processing steps to provide information for efficient commercial-scale equipment design and operation; (2) device characterization relating the device performance to materials properties and process conditions; (3) development of alloy materials with different bandgaps to allow improved device structures for stability and compatibility with module design; (4) development and improved window/heterojunction layers and contacts to improve device performance and reliability; and (5) evaluation of cell stability with respect to device structure and module encapsulation.

  15. New method for selection of hydrogen peroxide adapted bifidobacteria cells using continuous culture and immobilized cell technology

    Directory of Open Access Journals (Sweden)

    Meile Leo

    2010-07-01

    Full Text Available Abstract Background Oxidative stress can severely compromise viability of bifidobacteria. Exposure of Bifidobacterium cells to oxygen causes accumulation of reactive oxygen species, mainly hydrogen peroxide, leading to cell death. In this study, we tested the suitability of continuous culture under increasing selective pressure combined with immobilized cell technology for the selection of hydrogen peroxide adapted Bifidobacterium cells. Cells of B. longum NCC2705 were immobilized in gellan-xanthan gum gel beads and used to continuously ferment MRS medium containing increasing concentration of H2O2 from 0 to 130 ppm. Results At the beginning of the culture, high cell density of 1013 CFU per litre of reactor was tested. The continuous culture gradually adapted to increasing H2O2 concentrations. However, after increasing the H2O2 concentration to 130 ppm the OD of the culture decreased to 0. Full wash out was prevented by the immobilization of the cells in gel matrix. Hence after stopping the stress, it was possible to re-grow the cells that survived the highest lethal dose of H2O2 and to select two adapted colonies (HPR1 and HPR2 after plating of the culture effluent. In contrast to HPR1, HPR2 showed stable characteristics over at least 70 generations and exhibited also higher tolerance to O2 than non adapted wild type cells. Preliminary characterization of HPR2 was carried out by global genome expression profile analysis. Two genes coding for a protein with unknown function and possessing trans-membrane domains and an ABC-type transporter protein were overexpressed in HPR2 cells compared to wild type cells. Conclusions Our study showed that continuous culture with cell immobilization is a valid approach for selecting cells adapted to hydrogen peroxide. Elucidation of H2O2 adaptation mechanisms in HPR2 could be helpful to develop oxygen resistant bifidobacteria.

  16. Selective assembly of laminin variants by human carcinoma cells

    DEFF Research Database (Denmark)

    Wewer, U M; Wayner, E A; Hoffstrom, B G

    1994-01-01

    BACKGROUND: The laminins are heterotrimeric basement membrane glycoproteins. Eight subunits that can be assembled into laminins have been characterized and are known as: A, B1, B2, S, M, K, B2t, B1k laminin chains. Although many neoplastic cells secrete laminins and some of them even assemble bas...

  17. Adherence to hydroxyurea medication by children with sickle cell disease (SCD) using an electronic device: a feasibility study.

    Science.gov (United States)

    Inoue, Susumu; Kodjebacheva, Gergana; Scherrer, Tammy; Rice, Gary; Grigorian, Matthew; Blankenship, Jeremy; Onwuzurike, Nkechi

    2016-08-01

    Adherence to hydroxyurea (HU) is a significant modifying factor in sickle cell vaso-occlusive pain. We conducted a study using an electronic medication container-monitor-reminder device (GlowCap™) to track adherence and determine whether use of this device affected rates of HU adherence. Subjects were regular attendees to our clinic. They were given a 37-item questionnaire and were asked to use a GlowCap containing HU. When the device cap is opened, it makes a remote "medication taken" record. The device also provides usage reminder in the form of lights and alarm sounds if the cap opening is delayed. Nineteen subjects participated in the survey, and 17 in the intervention phase. Of the 17, 12 had reliable adherence data. Seventeen caregivers of patients and two patients completed the survey. Two most common barriers to adherence identified were lack of reminders and absence of medicine home delivery. The intervention component of this study, which used both the electronic (GlowCap) method and medication possession ratio showed that the median adherence rate for the 12 patients evaluated was 85 %. The GlowCap device accurately kept a record of adherence rates. This device may be an effective tool for increasing HU medication adherence.

  18. Study of a novel cell lysis method with titanium dioxide for Lab-on-a-Chip devices.

    Science.gov (United States)

    Wan, Weijie; Yeow, John T W

    2011-06-01

    In this paper, a novel method is proposed and demonstrated to be able to lyse gram-negative (E. coli) bacteria cells for Lab-on-a-Chip applications. The proposed method incorporates using titanium dioxide particles as photocatalysts and a miniaturized UV LED array as an excitation light source to perform cell lysis on microchips. The experimental result demonstrates the feasibility of the proposed prototype device. The working device suggests an inexpensive, easy to be fabricated and effective way for microchip cell lysis. The miniaturized UV LED array and the microchip with a reaction chamber can be easily integrated with other functional components to form a customized whole Lab-on-a-Chip system.

  19. Single wearable sensing energy device based on photoelectric biofuel cells for simultaneous analysis of perspiration and illuminance.

    Science.gov (United States)

    Yu, You; Zhai, Junfeng; Xia, Yong; Dong, Shaojun

    2017-08-24

    Wearable electronics are essential for the construction of epidermal energy supply and portable healthcare devices. Herein, a self-powered wearable electronic device based on a photoelectric biofuel cell has been introduced for the first time to simultaneously detect the perspiration lactate and monitor the ambient illuminance depending on independent parameters. The functions of harvesting energy, detection of body function and monitoring of ambient have been merged into a single wireless sensor. This novel design may provide a wide range of smart and exciting wearable electronics.

  20. Characterization of Damp-Heat Degradation of CuInGaSe2 Solar Cell Components and Devices by (Electrochemical) Impedance Spectroscopy: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Pern, F. J. J.; Noufi, R.

    2011-09-01

    This work evaluated the capability of (electrochemical) impedance spectroscopy (IS, or ECIS as used here) to monitor damp heat (DH) stability of contact materials, CuInGaSe2 (CIGS) solar cell components, and devices. Cell characteristics and its variation of the CIGS devices were also examined by the ECIS.

  1. Proteostasis in striatal cells and selective neurodegeneration in Huntington's disease.

    Science.gov (United States)

    Margulis, Julia; Finkbeiner, Steven

    2014-01-01

    Selective neuronal loss is a hallmark of neurodegenerative diseases, including Huntington's disease (HD). Although mutant huntingtin, the protein responsible for HD, is expressed ubiquitously, a subpopulation of neurons in the striatum is the first to succumb. In this review, we examine evidence that protein quality control pathways, including the ubiquitin proteasome system, autophagy, and chaperones, are significantly altered in striatal neurons. These alterations may increase the susceptibility of striatal neurons to mutant huntingtin-mediated toxicity. This novel view of HD pathogenesis has profound therapeutic implications: protein homeostasis pathways in the striatum may be valuable targets for treating HD and other misfolded protein disorders.

  2. Nitrilase-Activatable Noncanonical Amino Acid Precursors for Cell-Selective Metabolic Labeling of Proteomes.

    Science.gov (United States)

    Li, Zefan; Zhu, Yuntao; Sun, Yuting; Qin, Ke; Liu, Weibing; Zhou, Wen; Chen, Xing

    2016-12-16

    Cell-selective protein metabolic labeling is of great interest for studying cell-cell communications and tissue homeostasis. We herein describe a nitrilase-activatable noncanonical amino acid tagging (NANCAT) strategy that exploits an exogenous nitrilase to enzymatically convert the nitrile-substituted precursors to their corresponding noncanonical amino acids (ncAAs), l-azidohomoalanine (Aha) or homopropargylglycine (Hpg), in living cells. Only cells expressing the nitrilase can generate Aha or Hpg in cellulo and metabolically incorporate them into the nascent proteins. Subsequent click-labeling of the azide- or alkyne-incorporated proteins with fluorescent probes or with affinity tags enables visualization and proteomic profiling of nascent proteomes, respectively. We have demonstrated that NANCAT can serve as a versatile strategy for cell-selective labeling of proteomes in both bacterial and mammalian cells.

  3. Antiproliferative Effects of Selected Chemotherapeutics in Human Ovarian Cancer Cell Line A2780

    Directory of Open Access Journals (Sweden)

    Kateřina Caltová

    2012-01-01

    Full Text Available The aim of our study was to determine the effect of selected cytostatics on a human ovarian cancer cell line A2780 as a model system for ovarian cancer treatment. This cell line is considered cisplatin-sensitive. Panel of tested cytostatics included cisplatin, paclitaxel, carboplatin, gemcitabine, topotecan and etoposide. These cytostatics have a different mechanism of action. To evaluate cytotoxic potential of the tested compounds, the methods measuring various toxicological endpoints were employed including morphological studies, MTT assay, dynamic monitoring of cell proliferation with xCELLigence, cell cycle analysis, caspase 3 activity and expression of proteins involved in cell cycle regulation and cell death. The A270 cell line showed different sensitivity towards the selected cytostatics, the highest cytotoxic effect was associated with paclitaxel and topotecan.

  4. Isolation of Circulating Plasma Cells in Multiple Myeloma Using CD138 Antibody-Based Capture in a Microfluidic Device

    Science.gov (United States)

    Qasaimeh, Mohammad A.; Wu, Yichao C.; Bose, Suman; Menachery, Anoop; Talluri, Srikanth; Gonzalez, Gabriel; Fulciniti, Mariateresa; Karp, Jeffrey M.; Prabhala, Rao H.; Karnik, Rohit

    2017-04-01

    The necessity for bone marrow aspiration and the lack of highly sensitive assays to detect residual disease present challenges for effective management of multiple myeloma (MM), a plasma cell cancer. We show that a microfluidic cell capture based on CD138 antigen, which is highly expressed on plasma cells, permits quantitation of rare circulating plasma cells (CPCs) in blood and subsequent fluorescence-based assays. The microfluidic device is based on a herringbone channel design, and exhibits an estimated cell capture efficiency of ~40-70%, permitting detection of numbers in blood samples of MM patients in remission (20-24 CD138+ cells/mL), and yet higher numbers in MM patients exhibiting disease (45-184 CD138+ cells/mL). Analysis of CPCs isolated using the device was consistent with serum immunoglobulin assays that are commonly used in MM diagnostics. These results indicate the potential of CD138-based microfluidic CPC capture as a useful ‘liquid biopsy’ that may complement or partially replace bone marrow aspiration.

  5. Selection of scFvs specific for the HepG2 cell line using ribosome ...

    Indian Academy of Sciences (India)

    In order to isolate specific scFvs, recognizing HepG2 negative selection on a normal hepatocyte line WRL-68 was carried out before three rounds of positive selection on HepG2. After three rounds of panning, cell enzyme-linked immunosorbent assay (ELISA) showed that one of the scFvs had high affinity for the HepG2 cell ...

  6. The effect of BAFF inhibition on autoreactive B cell selection in murine SLE.

    Science.gov (United States)

    Boneparth, Alexis; Woods, Megan; Huang, Weiqing; Akerman, Meredith; Lesser, Martin; Davidson, Anne

    2016-02-12

    The goal of this study was to determine how BAFF availability influences selection of the autoreactive B cell repertoire in NZB/W and NZW/BXSB lupus prone mice bearing the site-directed heavy chain transgene 3H9 that encodes for anti-dsDNA and anti-CL autoantibodies. We used a bone marrow chimera system in which autoreactive 3H9 transgenic B cells were allowed to mature in competition with wild type cells and could be identified by GFP fluorescence. The light chain repertoire associated with the 3H9 heavy chain in naïve and antigen-activated B cell subsets was assessed using single cell PCR. We found that deletion of autoreactive transgenic B cells occurred in the bone marrow of both strains regardless of BAFF availability and there were only modest and physiologically non-relevant effects on the naïve B cell repertoire. BAFF inhibition had different effects on selection of the germinal center repertoire in the two strains. In the NZW/BXSB strain, BAFF inhibition phenocopied the loss of one TLR7 allele in that it influenced the selection of 3H9 encoded autoreactive B cells in the germinal center but did not prevent somatic mutation. In the NZB/W strain BAFF inhibition did not alter the selection of 3H9 encoded B cells in the germinal center but it influenced selection of a subset of germinal center cells into the plasma cell compartment. Our data underscore the complexity of regulation of the autoreactive B cell repertoire by BAFF and may help to explain the heterogeneity of responses observed after BAFF inhibition in humans.

  7. A nanocomplex that is both tumor cell-selective and cancer gene-specific for anaplastic large cell lymphoma

    Directory of Open Access Journals (Sweden)

    Zu Youli

    2011-01-01

    Full Text Available Abstract Background Many in vitro studies have demonstrated that silencing of cancerous genes by siRNAs is a potential therapeutic approach for blocking tumor growth. However, siRNAs are not cell type-selective, cannot specifically target tumor cells, and therefore have limited in vivo application for siRNA-mediated gene therapy. Results In this study, we tested a functional RNA nanocomplex which exclusively targets and affects human anaplastic large cell lymphoma (ALCL by taking advantage of the abnormal expression of CD30, a unique surface biomarker, and the anaplastic lymphoma kinase (ALK gene in lymphoma cells. The nanocomplexes were formulated by incorporating both ALK siRNA and a RNA-based CD30 aptamer probe onto nano-sized polyethyleneimine-citrate carriers. To minimize potential cytotoxicity, the individual components of the nanocomplexes were used at sub-cytotoxic concentrations. Dynamic light scattering showed that formed nanocomplexes were ~140 nm in diameter and remained stable for more than 24 hours in culture medium. Cell binding assays revealed that CD30 aptamer probes selectively targeted nanocomplexes to ALCL cells, and confocal fluorescence microscopy confirmed intracellular delivery of the nanocomplex. Cell transfection analysis showed that nanocomplexes silenced genes in an ALCL cell type-selective fashion. Moreover, exposure of ALCL cells to nanocomplexes carrying both ALK siRNAs and CD30 RNA aptamers specifically silenced ALK gene expression, leading to growth arrest and apoptosis. Conclusions Taken together, our findings indicate that this functional RNA nanocomplex is both tumor cell type-selective and cancer gene-specific for ALCL cells.

  8. Injection molded pinched flow fractionation device for enrichment of somatic cells in cow milk

    DEFF Research Database (Denmark)

    Jensen, Marie Pødenphant; Marie, Rodolphe; Olesen, Tom

    2014-01-01

    . The enrichment was performed using an all-polymer pinched flow fractionation device fabricated by injection molding. The polymer chips were bonded to a 500 lm polymer foil using UV assisted thermal bonding. The quality of the final devices was reproducible and the injection molding process combined with the use...

  9. Band Edge Positions and Their Impact on the Simulated Device Performance of ZnSnN2-Based Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Arca, Elisabetta [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Fioretti, Angela [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Lany, Stephan [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Tamboli, Adele C [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Teeter, Glenn R [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Melamed, Celeste [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Pan, Jie [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Wood, Kevin [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Toberer, Eric [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Zakutayev, Andriy A [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-12-07

    ZnSnN2 (ZTN) has been proposed as a new earth abundant absorber material for PV applications. While carrier concentration has been reduced to values suitable for device implementation, other properties such as ionization potential, electron affinity and work function are not known. Here, we experimentally determine the value of ionization potential (5.6 eV), electron affinity (4.1 eV) and work function (4.4 eV) for ZTN thin film samples with Zn cation composition Zn/(Zn+Sn) = 0.56 and carrier concentration n = 2x10^19 cm^-3. Using both experimental and theoretical results, we build a model to simulate the device performance of a ZTN/Mg:CuCrO2 solar cell, showing a potential efficiency of 23% in the limit of no defects present. We also investigate the role of band tails and recombination centers on the cell performance. In particular device simulations show that band tails are highly detrimental to the cell efficiency, and recombination centers are a major limitation if present in concentration comparable to the net carrier density. The effect of the position of the band edges of the p-type junction partner was assessed too. Through this study, we determine the major bottlenecks for the development of ZTN-based solar cell and identify avenues to mitigate them.

  10. Development of microfluidic devices for in situ investigation of cells using surface-enhanced Raman spectroscopy (Conference Presentation)

    Science.gov (United States)

    Ho, Yu-Han; Galvan, Daniel D.; Yu, Qiuming

    2016-03-01

    Surface-enhanced Raman spectroscopy (SERS) has immerged as a power analytical and sensing technique for many applications in biomedical diagnosis, life sciences, food safety, and environment monitoring because of its molecular specificity and high sensitivity. The inactive Raman scattering of water molecule makes SERS a suitable tool for studying biological systems. Microfluidic devices have also attracted a tremendous interest for the aforementioned applications. By integrating SERS-active substrates with microfluidic devices, it offers a new capability for in situ investigation of biological systems, their dynamic behaviors, and response to drugs or microenvironment changes. In this work, we designed and fabricated a microfluidic device with SERS-active substrates surrounding by cell traps in microfluidic channels for in situ study of live cells using SERS. The SERS-active substrates are quasi-3D plasmonic nanostructure array (Q3D-PNA) made in h-PDMS/PMDS with physically separated gold film with nanoholes op top and gold nanodisks at the bottom of nanowells. 3D finite-difference time-domain (3D-FDTD) electromagnetic simulations were performed to design Q3D-PNAs with the strongest local electric fields (hot spots) at the top or bottom water/Au interfaces for sensitive analysis of cells and small components, respectively. The Q3D-PNAs with the hot spots on top and bottom were placed at the up and down stream of the microfluidic channel, respectively. Each Q3D-PNA pattern was surrounded with cell trapping structures. The microfluidic device was fabricated via soft lithography. We demonstrated that normal (COS-7) and cancer (HpeG2) cells were captured on the Q3D-PNAs and investigated in situ using SERS.

  11. Selective apoptosis induction in MCF-7 cell line by truncated minimal functional region of Apoptin

    International Nuclear Information System (INIS)

    Shen Ni, Lim; Allaudin, Zeenathul Nazariah bt; Mohd Lila, Mohd Azmi b; Othman, Abas Mazni b; Othman, Fauziah bt

    2013-01-01

    Chicken Anemia Virus (CAV) VP3 protein (also known as Apoptin), a basic and proline-rich protein has a unique capability in inducing apoptosis in cancer cells but not in normal cells. Five truncated Apoptin proteins were analyzed to determine their selective ability to migrate into the nucleus of human breast adenocarcinoma MCF-7 cells for inducing apoptosis. For identification of the minimal selective domain for apoptosis, the wild-type Apoptin gene had been reconstructed by PCR to generate segmental deletions at the N’ terminal and linked with nuclear localization sites (NLS1 and NLS2). All the constructs were fused with maltose-binding protein gene and individually expressed by in vitro Rapid Translation System. Standardized dose of proteins were delivered into human breast adenocarcinoma MCF-7 cells and control human liver Chang cells by cytoplasmic microinjection, and subsequently observed for selective apoptosis effect. Three of the truncated Apoptin proteins with N-terminal deletions spanning amino acid 32–83 retained the cancer selective nature of wild-type Apoptin. The proteins were successfully translocated to the nucleus of MCF-7 cells initiating apoptosis, whereas non-toxic cytoplasmic retention was observed in normal Chang cells. Whilst these truncated proteins retained the tumour-specific death effector ability, the specificity for MCF-7 cells was lost in two other truncated proteins that harbor deletions at amino acid 1–31. The detection of apoptosing normal Chang cells and MCF-7 cells upon cytoplasmic microinjection of these proteins implicated a loss in Apoptin’s signature targeting activity. Therefore, the critical stretch spanning amino acid 1–31 at the upstream of a known hydrophobic leucine-rich stretch (LRS) was strongly suggested as one of the prerequisite region in Apoptin for cancer targeting. Identification of this selective domain provides a platform for developing small targets to facilitating carrier-mediated-transport across

  12. Cell-selective labeling of bacterial proteomes with an orthogonal phenylalanine amino acid reporter.

    Science.gov (United States)

    Grammel, Markus; Dossa, Paul D; Taylor-Salmon, Emma; Hang, Howard C

    2012-02-01

    Orthogonal amino acid reporters allow the selective labeling of different cell types in heterogeneous populations through the expression of engineered aminoacyl tRNA synthetases. Here, we demonstrate that para-ethynylphenylalanine (PEP) can be used as an orthogonal amino acid reporter for efficient selective labeling of an intracellular bacterial pathogen during infection. This journal is © The Royal Society of Chemistry 2012

  13. Selection for antibody response against sheep red blood cells and layer age affect egg quality

    NARCIS (Netherlands)

    Brand, van den H.; Parmentier, H.K.; Kemp, B.

    2004-01-01

    1. After 22 generations of divergent selection for antibody response against sheep red blood cells (SRBC), hatchability differed between the selected lines. Whether there is a relationship between hatchability and egg traits in these lines is not clear. 2. The aim of the present study was to

  14. Selection of scFvs specific for the HepG2 cell line using ribosome ...

    Indian Academy of Sciences (India)

    Madhsudhan

    was transcribed and translated in vitro using a rabbit reticulocyte lysate system. In order to isolate specific scFvs, recognizing HepG2 negative selection on a normal hepatocyte line WRL-68 was carried out before three rounds of positive selection on HepG2. After three rounds of panning, cell enzyme-linked immunosorbent ...

  15. Schwann Cell Glycogen Selectively Supports Myelinated Axon Function

    Science.gov (United States)

    Brown, Angus M; Evans, Richard D; Black, Joel; Ransom, Bruce R

    2012-01-01

    Objectives Interruption of energy supply to peripheral axons is a cause of axon loss. We determined if glycogen was present in mammalian peripheral nerve, and if it supported axon conduction during aglycemia. Methods We used biochemical assay and electron microscopy to determine the presence of glycogen, and electrophysiology to monitor axon function. Results Glycogen was present in sciatic nerve, its concentration varying directly with ambient [glucose]. Electron microscopy detected glycogen granules primarily in myelinating Schwann cell cytoplasm and these diminished after exposure to aglycemia. During aglycemia, conduction failure in large myelinated axons (A fibers) mirrored the time-course of glycogen loss. Latency to CAP failure was directly related to nerve glycogen content at aglycemia onset. Glycogen did not benefit the function of slow-conducting, small diameter unmyelinated axons (C fibers) during aglycemia. Blocking glycogen breakdown pharmacologically accelerated CAP failure during aglycemia in A fibers, but not in C fibers. Lactate was as effective as glucose in supporting sciatic nerve function, and was continuously released into the extracellular space in the presence of glucose and fell rapidly during aglycemia. Interpretation Our findings indicated that glycogen is present in peripheral nerve, primarily in myelinating Schwann cells, and exclusively supports large diameter, myelinated axon conduction during aglycemia. Available evidence suggests that peripheral nerve glycogen breaks down during aglycemia and is passed, probably as lactate, to myelinated axons to support function. Unmyelinated axons are not protected by glycogen and are more vulnerable to dysfunction during periods of hypoglycemia. PMID:23034913

  16. Electronic Devices, Methods, and Computer Program Products for Selecting an Antenna Element Based on a Wireless Communication Performance Criterion

    DEFF Research Database (Denmark)

    2014-01-01

    A method of operating an electronic device includes providing a plurality of antenna elements, evaluating a wireless communication performance criterion to obtain a performance evaluation, and assigning a first one of the plurality of antenna elements to a main wireless signal reception and trans...

  17. Signaling thresholds and negative B cell selection in acute lymphoblastic leukemia

    Science.gov (United States)

    Chen, Zhengshan; Shojaee, Seyedmehdi; Buchner, Maike; Geng, Huimin; Lee, Jae Woong; Klemm, Lars; Titz, Björn; Graeber, Thomas G.; Park, Eugene; Tan, Ying Xim; Satterthwaite, Anne; Paietta, Elisabeth; Hunger, Stephen P.; Willman, Cheryl L.; Melnick, Ari; Loh, Mignon L.; Jung, Jae U.; Coligan, John E.; Bolland, Silvia; Mak, Tak W.; Limnander, Andre; Jumaa, Hassan; Reth, Michael; Weiss, Arthur; Lowell, Clifford A.; Müschen, Markus

    2015-01-01

    B cells are selected for an intermediate level of B cell receptor (BCR) signaling strength: Attenuation below minimum (e.g. non-functional BCR)1 or hyperactivation above maximum (e.g. self-reactive BCR)2–3 thresholds of signaling strength causes negative selection. In ~25% of cases, acute lymphoblastic leukemia (ALL) cells carry the oncogenic BCR-ABL1 tyrosine kinase (Ph+), which mimics constitutively active pre-BCR signaling4,5. Current therapy approaches are largely focused on the development of more potent tyrosine kinase inhibitors to suppress oncogenic signaling below a minimum threshold for survival6. Here, we tested the hypothesis that targeted hyperactivation above a maximum threshold will engage a deletional checkpoint for removal of self-reactive B cells and selectively kill ALL cells. Testing various components of proximal pre-BCR signaling, we found that an incremental increase of Syk tyrosine kinase activity was required and sufficient to induce cell death. Hyperactive Syk was functionally equivalent to acute activation of a self-reactive BCR on ALL cells. Despite oncogenic transformation, this basic mechanism of negative selection was still functional in ALL cells. Unlike normal pre-B cells, patient-derived ALL cells express the inhibitory receptors PECAM1, CD300A and LAIR1 at high levels. Genetic studies revealed that Pecam1, Cd300a and Lair1 are critical to calibrate oncogenic signaling strength through recruitment of the inhibitory phosphatases Ptpn67 and Inpp5d8. Using a novel small molecule inhibitor of INPP5D9, we demonstrated that pharmacological hyperactivation of SYK and engagement of negative B cell selection represents a promising new strategy to overcome drug-resistance in human ALL. PMID:25799995

  18. Engineering human T cells for resistance to methotrexate and mycophenolate mofetil as an in vivo cell selection strategy.

    Directory of Open Access Journals (Sweden)

    Mahesh Jonnalagadda

    Full Text Available Gene transfer and drug selection systems that enforce ongoing transgene expression in vitro and in vivo which are compatible with human pharmaceutical drugs are currently underdeveloped. Here, we report on the utility of incorporating human enzyme muteins that confer resistance to the lymphotoxic/immunosuppressive drugs methotrexate (MTX and mycophenolate mofetil (MMF in a multicistronic lentiviral vector for in vivo T lymphocyte selection. We found that co-expression of human dihydrofolate reductase (DHFR(FS; L22F, F31S and inosine monophosphate dehydrogenase II (IMPDH2(IY; T333I, S351Y conferred T cell resistance to the cytocidal and anti-proliferative effects of these drugs at concentrations that can be achieved clinically (up to 0.1 µM MTX and 1.0 µM MPA. Furthermore, using a immunodeficient mouse model that supports the engraftment of central memory derived human T cells, in vivo selection studies demonstrate that huEGFRt(+DHFR(FS+IMPDH2(IY+ T cells could be enriched following adoptive transfer either by systemic administration of MTX alone (4.4 -fold, MMF alone (2.9-fold, or combined MTX and MMF (4.9-fold. These findings demonstrate the utility of both DHFR(FS/MTX and IMPDH2(IY/MMF for in vivo selection of lentivirally transduced human T cells. Vectors incorporating these muteins in combination with other therapeutic transgenes may facilitate the selective engraftment of therapeutically active cells in recipients.

  19. Engineering human T cells for resistance to methotrexate and mycophenolate mofetil as an in vivo cell selection strategy.

    Science.gov (United States)

    Jonnalagadda, Mahesh; Brown, Christine E; Chang, Wen-Chung; Ostberg, Julie R; Forman, Stephen J; Jensen, Michael C

    2013-01-01

    Gene transfer and drug selection systems that enforce ongoing transgene expression in vitro and in vivo which are compatible with human pharmaceutical drugs are currently underdeveloped. Here, we report on the utility of incorporating human enzyme muteins that confer resistance to the lymphotoxic/immunosuppressive drugs methotrexate (MTX) and mycophenolate mofetil (MMF) in a multicistronic lentiviral vector for in vivo T lymphocyte selection. We found that co-expression of human dihydrofolate reductase (DHFR(FS); L22F, F31S) and inosine monophosphate dehydrogenase II (IMPDH2(IY); T333I, S351Y) conferred T cell resistance to the cytocidal and anti-proliferative effects of these drugs at concentrations that can be achieved clinically (up to 0.1 µM MTX and 1.0 µM MPA). Furthermore, using a immunodeficient mouse model that supports the engraftment of central memory derived human T cells, in vivo selection studies demonstrate that huEGFRt(+)DHFR(FS+)IMPDH2(IY+) T cells could be enriched following adoptive transfer either by systemic administration of MTX alone (4.4 -fold), MMF alone (2.9-fold), or combined MTX and MMF (4.9-fold). These findings demonstrate the utility of both DHFR(FS)/MTX and IMPDH2(IY)/MMF for in vivo selection of lentivirally transduced human T cells. Vectors incorporating these muteins in combination with other therapeutic transgenes may facilitate the selective engraftment of therapeutically active cells in recipients.

  20. Induction and selection of mutants from in vitro cultured plant cells

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yung Il; Kim, Jae Sung; Shin, In Chul; Lee, Sang Jae [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1994-07-01

    Mutant cell lines are useful for biochemical, physiological and genetical material for marker in various genetic manipulation experiments and for the direct use in crop plant improvement. Mutant selection may lead to the production of plants showing resistance or tolerance to specific environmental stress, such as solinity, drought, toxed metals, herbicides, pathogens and low temperature. In this review, these included the production of the somatic variation, the selection process itself and stability of the selected characters in cell culture and regenerated plant. Which would seem to be useful for improving plants and securring genetic resources. 45 refs. (Author).

  1. Hypoxia selects bortezomib-resistant stem cells of chronic myeloid leukemia.

    Directory of Open Access Journals (Sweden)

    Michele Tanturli

    Full Text Available We previously demonstrated that severe hypoxia inhibits growth of Chronic Myeloid Leukemia (CML cells and selects stem cells where BCR/Abl(protein is suppressed, although mRNA is not, so that hypoxia-selected stem cells, while remaining leukemic, are independent of BCR/Abl signaling and thereby refractory to Imatinib-mesylate. The main target of this study was to address the effects of the proteasome inhibitor Bortezomib (BZ on the maintenance of stem or progenitor cells in hypoxic primary cultures (LC1, by determining the capacity of LC1 cells to repopulate normoxic secondary cultures (LC2 and the kinetics of this repopulation. Unselected K562 cells from day-2 hypoxic LC1 repopulated LC2 with rapid, progenitor-type kinetics; this repopulation was suppressed by BZ addition to LC1 at time 0, but completely resistant to day-1 BZ, indicating that progenitors require some time to adapt to stand hypoxia. K562 cells selected in hypoxic day-7 LC1 repopulated LC2 with stem-type kinetics, which was largely resistant to BZ added at either time 0 or day 1, indicating that hypoxia-selectable stem cells are BZ-resistant per se, i.e. before their selection. Furthermore, these cells were completely resistant to day-6 BZ, i.e. after selection. On the other hand, hypoxia-selected stem cells from CD34-positive cells of blast-crisis CML patients appeared completely resistant to either time-0 or day-1 BZ. To exploit in vitro the capacity of CML cells to adapt to hypoxia enabled to detect a subset of BZ-resistant leukemia stem cells, a finding of particular relevance in light of the fact that our experimental system mimics the physiologically hypoxic environment of bone marrow niches where leukemia stem cells most likely home and sustain minimal residual disease in vivo. This suggests the use of BZ as an enhanced strategy to control CML. in particular to prevent relapse of disease, to be considered with caution and to need further deepening.

  2. MD Study of Solution Concentrations on Ion Distribution in a Nanopore-Based Device Inspired from Red Blood Cells.

    Science.gov (United States)

    Ge, Yanyan; Xian, Jieyu; Kang, Min; Li, Xiaolin; Jin, Meifu

    2016-01-01

    A molecular dynamics model of a nanopore-based device, which is similar to the nanopores in a cell membrane, was used to determine the influence of solution concentration on radial ion distribution, screening effects, and the radial potential profile in the nanopore. Results from these simulations indicate that as the solution concentration increases, the density peaks for both the counterion and coion near the charged wall increase at different speeds as screening effects appeared. Consequently, the potential near the charged wall of the nanopore changed from negative to positive during the simulation. The detailed understanding of ion distribution in nanopores is important for controlling the ion permeability and improving the cell transfection and also the design and application of nanofluidic devices.

  3. Experimental Observation of Convective Cell Formation due to a Fast Wave Antenna in the Large Plasma Device.

    Science.gov (United States)

    Martin, M J; Gekelman, W; Van Compernolle, B; Pribyl, P; Carter, T

    2017-11-17

    An experiment in a linear device, the Large Plasma Device, is used to study sheaths caused by an actively powered radio frequency (rf) antenna. The rf antenna used in the experiment consists of a single current strap recessed inside a copper box enclosure without a Faraday screen. A large increase in the plasma potential was observed along magnetic field lines that connect to the antenna limiter. The electric field from the spatial variation of the rectified plasma potential generated E[over →]×B[over →]_{0} flows, often referred to as convective cells. The presence of the flows generated by these potentials is confirmed by Mach probes. The observed convective cell flows are seen to cause the plasma in front of the antenna to flow away and cause a density modification near the antenna edge. These can cause hot spots and damage to the antenna and can result in a decrease in the ion cyclotron range of frequencies antenna coupling.

  4. Black silicon laser-doped selective emitter solar cell with 18.1% efficiency

    DEFF Research Database (Denmark)

    Davidsen, Rasmus Schmidt; Li, Hongzhao; To, Alexander

    2016-01-01

    We report fabrication of nanostructured, laser-doped selective emitter (LDSE) silicon solar cells with power conversion efficiency of 18.1% and a fill factor (FF) of 80.1%. The nanostructured solar cells were realized through a single step, mask-less, scalable reactive ion etch (RIE) texturing......-texturing as well as the LDSE process, we consider this specific combination a promising candidate for a cost-efficient process for future Si solar cells....

  5. Evodiamine selectively targets cancer stem-like cells through the p53-p21-Rb pathway

    International Nuclear Information System (INIS)

    Han, Seula; Woo, Jong Kyu; Jung, Yuchae; Jeong, Dawoon; Kang, Minsook; Yoo, Young-Ji; Lee, Hani; Oh, Seung Hyun; Ryu, Jae-Ha; Kim, Woo-Young

    2016-01-01

    In spite of the recent improvements, the resistance to chemotherapy/radiotherapy followed by relapse is the main hurdle for the successful treatment of breast cancer, a leading cause of death in women. A small population of breast cancer cells that have stem-like characteristics (cancer stem-like cells; CSLC) may contribute to this resistance and relapse. Here, we report on a component of a traditional Chinese medicine, evodiamine, which selectively targets CSLC of breast cancer cell lines MCF7 and MDAMB 231 at a concentration that does show a little or no cytotoxic effect on bulk cancer cells. While evodiamine caused the accumulation of bulk cancer cells at the G2/M phase, it did not hold CSLC in a specific cell cycle phase but instead, selectively killed CSLC. This was not due to the culture of CSLC in suspension or without FBS. A proteomic analysis and western blotting revealed that evodiamine changed the expression of cell cycle regulating molecules more efficiently in CSLC cells than in bulk cancer cells. Surprisingly, evodiamine selectively activated p53 and p21 and decreased inactive Rb, the master molecules in G1/S checkpoint. These data collectively suggest a novel mechanism involving CSLC-specific targeting by evodiamine and its possible use to the therapy of breast cancer. - Highlights: • Evodiamine selectively kills breast cancer stem like cells at G1 phase. • Evodiamine utilizes different mechanism of cell cycle modulation in CSLC and in bulk cancer cells. • Evodiamine activate the p53, p21 and Rb pathway.

  6. Evodiamine selectively targets cancer stem-like cells through the p53-p21-Rb pathway

    Energy Technology Data Exchange (ETDEWEB)

    Han, Seula [The Research Center for Cell Fate Control, College of Pharmacy, Sookmyung Women' s University, Seoul (Korea, Republic of); Woo, Jong Kyu [College of Pharmacy, Gachon University, Incheon (Korea, Republic of); Jung, Yuchae; Jeong, Dawoon; Kang, Minsook; Yoo, Young-Ji; Lee, Hani [The Research Center for Cell Fate Control, College of Pharmacy, Sookmyung Women' s University, Seoul (Korea, Republic of); Oh, Seung Hyun [College of Pharmacy, Gachon University, Incheon (Korea, Republic of); Ryu, Jae-Ha [The Research Center for Cell Fate Control, College of Pharmacy, Sookmyung Women' s University, Seoul (Korea, Republic of); Kim, Woo-Young, E-mail: wykim@sookmyung.ac.kr [The Research Center for Cell Fate Control, College of Pharmacy, Sookmyung Women' s University, Seoul (Korea, Republic of)

    2016-01-22

    In spite of the recent improvements, the resistance to chemotherapy/radiotherapy followed by relapse is the main hurdle for the successful treatment of breast cancer, a leading cause of death in women. A small population of breast cancer cells that have stem-like characteristics (cancer stem-like cells; CSLC) may contribute to this resistance and relapse. Here, we report on a component of a traditional Chinese medicine, evodiamine, which selectively targets CSLC of breast cancer cell lines MCF7 and MDAMB 231 at a concentration that does show a little or no cytotoxic effect on bulk cancer cells. While evodiamine caused the accumulation of bulk cancer cells at the G2/M phase, it did not hold CSLC in a specific cell cycle phase but instead, selectively killed CSLC. This was not due to the culture of CSLC in suspension or without FBS. A proteomic analysis and western blotting revealed that evodiamine changed the expression of cell cycle regulating molecules more efficiently in CSLC cells than in bulk cancer cells. Surprisingly, evodiamine selectively activated p53 and p21 and decreased inactive Rb, the master molecules in G1/S checkpoint. These data collectively suggest a novel mechanism involving CSLC-specific targeting by evodiamine and its possible use to the therapy of breast cancer. - Highlights: • Evodiamine selectively kills breast cancer stem like cells at G1 phase. • Evodiamine utilizes different mechanism of cell cycle modulation in CSLC and in bulk cancer cells. • Evodiamine activate the p53, p21 and Rb pathway.

  7. A directionally-selective neuromorphic circuit based on reciprocal synapses in Starburst Amacrine Cells.

    Science.gov (United States)

    Tseng, Ko-Chung; Parker, Alice C; Joshi, Jonathan

    2011-01-01

    Starburst Amacrine Cells (SACs) play a major role in the detection of directional motion in the biological retina. The starburst amacrine cell has intrinsic electrical mechanisms for producing directional selectivity (DS). GABA transmitter-receptor interactions between two overlapping SACs make DS more robust. We present a compartmentalized CMOS neuromorphic circuit that models a portion of two biological starburst amacrine cells in the retina and includes a simplified model of reciprocal interaction between the dendritic branches of SACs. We demonstrate that a neuromorphic circuit incorporating the reciprocal synapses enhances the responses in the neuromorphic dendritic tip and generates robust directional selectivity.

  8. Optoelectronic simulation of GaAs solar cells with angularly selective filters

    International Nuclear Information System (INIS)

    Kraus, Tobias; Höhn, Oliver; Hauser, Hubert; Bläsi, Benedikt

    2014-01-01

    We discuss the influence of angularly selective filters on thin film gallium arsenide solar cells. For this reason, the detailed balance model was refined to fit our needs with respect to Auger recombination, reflection, transmission, and realistic absorption. For calculating real systems, an approach was made to include optical effects of angularly selective filters into electron-hole dynamic equations implemented in PC1D, a one dimensional solar cell calculation tool. With this approach, we find a relative V oc increase of 5% for an idealized 100 nm GaAs cell, including Auger recombination

  9. Distinct transcriptional programs in thymocytes responding to T cell receptor, Notch, and positive selection signals

    OpenAIRE

    Huang, Yina H.; Li, Dongling; Winoto, Astar; Robey, Ellen A.

    2004-01-01

    T cell antigen receptor (TCR) signaling is necessary but not sufficient to promote the positive selection of CD4+CD8+ thymocytes into CD4+ or CD8+ mature T cells. Notch signaling has also been implicated as a potential regulator of both CD4/CD8 T cell development and TCR signaling. However, the relationship between positive selection, TCR signaling, and Notch remains unclear. Here we use DNA microarray analysis to compare gene expression changes in CD4+CD8+ double-positive thymocytes undergoi...

  10. Mitochondrial Complex I Inhibitors Expose a Vulnerability for Selective Killing of Pten-Null Cells.

    Science.gov (United States)

    Naguib, Adam; Mathew, Grinu; Reczek, Colleen R; Watrud, Kaitlin; Ambrico, Alexandra; Herzka, Tali; Salas, Irene Casanova; Lee, Matthew F; El-Amine, Nour; Zheng, Wu; Di Francesco, M Emilia; Marszalek, Joseph R; Pappin, Darryl J; Chandel, Navdeep S; Trotman, Lloyd C

    2018-04-03

    A hallmark of advanced prostate cancer (PC) is the concomitant loss of PTEN and p53 function. To selectively eliminate such cells, we screened cytotoxic compounds on Pten -/- ;Trp53 -/- fibroblasts and their Pten-WT reference. Highly selective killing of Pten-null cells can be achieved by deguelin, a natural insecticide. Deguelin eliminates Pten-deficient cells through inhibition of mitochondrial complex I (CI). Five hundred-fold higher drug doses are needed to obtain the same killing of Pten-WT cells, even though deguelin blocks their electron transport chain equally well. Selectivity arises because mitochondria of Pten-null cells consume ATP through complex V, instead of producing it. The resulting glucose dependency can be exploited to selectively kill Pten-null cells with clinically relevant CI inhibitors, especially if they are lipophilic. In vivo, deguelin suppressed disease in our genetically engineered mouse model for metastatic PC. Our data thus introduce a vulnerability for highly selective targeting of incurable PC with inhibitors of CI. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

  11. Treatment selection for squamous cell carcinoma of oropharynx

    Energy Technology Data Exchange (ETDEWEB)

    Inakami, Ken-ichi; Sato, Takeo; Yoshino, Kunitoshi; Fujii, Takashi; Nagahara, Masamitu; Momohara, Chikahiro [Osaka Prefectural Center for Adult Diseases (Japan)

    1999-03-01

    Between 1979 and 1995, 153 patients were treated for squamous cell carcinoma of the oropharynx (except the posterior wall region). All patients had a minimum 2-year follow-up and no patient was lost to follow-up. The distribution according to primary site was as follows: base of tongue region, 41 lesions; tonsillar fossa region, 71 lesions; and anterior tonsillar pillar and soft palate region, 41 lesions. The T1 and T2 tumors treated with surgery or radiotherapy had control rates of 29/33 (88%) and 48/66 (73%), respectively. The base of the tongue and tonsillar fossa region had good local control rates in both surgery and radiotherapy. In the anterior tonsillar pillar and soft palate region, however, the initial control by radiotherapy and surgery was T1 and T2 of 8/ 21 (38%) and T1 and T2 of 8/9 (89%) respectively. The ultimate local control rate after surgical salvage was 25 (83%) of 30 patients. Surgical salvage was often successful for early lesions. Surgery is an effective form of treatment for carcinoma of the soft palate and tonsillar pillar. (author)

  12. Feasibility of cell transplantation with a left ventricular assist device to improve the success rate of left ventricular assist device removal: the first experiment.

    Science.gov (United States)

    Mizuno, Tomohiro

    2011-01-01

    Left ventricular assist devices (LVADs) greatly support heart recovery, but recurrent heart failure after LVAD removal limits their use as 'a bridge to recovery'. The combination of LVADs and cell transplantation (CTx) is expected to be effective to improve the success rate of LVAD removal. We investigated the feasibility of combined CTx therapy and LVAD support with a new heterotopic rat heart-lung transplantation model that could simulate LVAD support and LVAD removal. The heart and both lungs of a rat were heterotopically transplanted, and the heart was kept unloaded for two weeks. The heart was then reloaded for two weeks (LVAD group). Syngenic smooth muscle cells were transplanted into the hearts that had been unloaded for a week, and the hearts were kept unloaded for another week and then reloaded (CT-LVAD group). In the unloaded state, CTx could reduce the left ventricle (LV) volume more effectively than LVAD therapy alone (P<0.01) and maintain the LV volume even after the hearts were reloaded (P<0.01). The results suggest that CTx with LVAD support can prevent recurrent LV dilation after LVAD removal and improve the success rate of LVAD removal.

  13. Antigen-affinity controls pregerminal centser B cell selection by promoting Mcl-1 induction through BAFF receptor signaling

    NARCIS (Netherlands)

    Wensveen, Felix M.; Slinger, Erik; van Attekum, Martijn H. A.; Brink, Robert; Eldering, Eric

    2016-01-01

    Upon antigen encounter, the responsive B cell pool undergoes stringent selection which eliminates cells with low B cell receptor (BCR) affinity. Already before formation of the germinal center, activated B cells of low-affinity are negatively selected in a process that is molecularly not well

  14. The endoplasmic reticulum is partitioned asymmetrically during mitosis before cell fate selection in proneuronal cells in the early Drosophila embryo

    Science.gov (United States)

    Eritano, Anthony S.; Altamirano, Arturo; Beyeler, Sarah; Gaytan, Norma; Velasquez, Mark; Riggs, Blake

    2017-01-01

    Asymmetric cell division is the primary mechanism to generate cellular diversity, and it relies on the correct partitioning of cell fate determinants. However, the mechanism by which these determinants are delivered and positioned is poorly understood, and the upstream signal to initiate asymmetric cell division is unknown. Here we report that the endoplasmic reticulum (ER) is asymmetrically partitioned during mitosis in epithelial cells just before delamination and selection of a proneural cell fate in the early Drosophila embryo. At the start of gastrulation, the ER divides asymmetrically into a population of asynchronously dividing cells at the anterior end of the embryo. We found that this asymmetric division of the ER depends on the highly conserved ER membrane protein Jagunal (Jagn). RNA inhibition of jagn just before the start of gastrulation disrupts this asymmetric division of the ER. In addition, jagn-deficient embryos display defects in apical-basal spindle orientation in delaminated embryonic neuroblasts. Our results describe a model in which an organelle is partitioned asymmetrically in an otherwise symmetrically dividing cell population just upstream of cell fate determination and updates previous models of spindle-based selection of cell fate during mitosis. PMID:28381427

  15. The Use of Photoelectric Cells as Sources of Power for Anti fly Biophysical Devices

    International Nuclear Information System (INIS)

    Aliev, R.; Aliboev, M.; Bazarov, O.; Tulanova, B.

    2011-01-01

    An anti fly biophysical device is developed and optimized. It has a luminescent bulb, solid emitters, and a photoelectric power source. Promising uses of industrial photoelectric batteries are proposed, and the feasibility of their adoption in agriculture is shown. (authors)

  16. Phenotypic plasticity and effects of selection on cell division symmetry in Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Uttara N Lele

    Full Text Available Aging has been demonstrated in unicellular organisms and is presumably due to asymmetric distribution of damaged proteins and other components during cell division. Whether the asymmetry-induced aging is inevitable or an adaptive and adaptable response is debated. Although asymmetric division leads to aging and death of some cells, it increases the effective growth rate of the population as shown by theoretical and empirical studies. Mathematical models predict on the other hand, that if the cells divide symmetrically, cellular aging may be delayed or absent, growth rate will be reduced but growth yield will increase at optimum repair rates. Therefore in nutritionally dilute (oligotrophic environments, where growth yield may be more critical for survival, symmetric division may get selected. These predictions have not been empirically tested so far. We report here that Escherichia coli grown in oligotrophic environments had greater morphological and functional symmetry in cell division. Both phenotypic plasticity and genetic selection appeared to shape cell division time asymmetry but plasticity was lost on prolonged selection. Lineages selected on high nutrient concentration showed greater frequency of presumably old or dead cells. Further, there was a negative correlation between cell division time asymmetry and growth yield but there was no significant correlation between asymmetry and growth rate. The results suggest that cellular aging driven by asymmetric division may not be hardwired but shows substantial plasticity as well as evolvability in response to the nutritional environment.

  17. Performance of a Microfluidic Device for In Situ ToF-SIMS Analysis of Selected Organic Molecules at Aqueous Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Li; Zhu, Zihua; Yu, Xiao-Ying; Thevuthasan, Suntharampillai; Cowin, James P.

    2013-04-03

    Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is a unique surface analysis technique because it can provide molecular recognition for organic and biological molecules. However, analyzing aqueous solution surfaces by ToF-SIMS is difficult, because ToF-SIMS is a high-vacuum technique, while the vapor pressure of water is about 2.3 kPa at room temperature (20 C). We designed and fabricated a self-contained microfluidic device, enabling in situ analysis of aqueous surfaces by scanning electron microscope (SEM) and ToF-SIMS, which has been briefly reported.1,2 In this study, we report more performance data, focusing on the performance of this device for in situ analysis of organic molecules at aqueous surfaces using ToF-SIMS. Three representative organic compounds (formic acid, glycerol, and glutamic acid) were tested, and their molecular signals were successfully observed. The device can be self-running in vacuum for 8 hours, and SIMS measurements are feasible at any time in this time range. The stability of this device under primary ion beam bombardment is also impressive. High fluence (6 × 1012 ions cm-2 s-1) measurements can be operated continuously for up to 30 minutes without any significant damage to the aperture. However, extra-high fluence measurements (>1 × 1014 ions cm-2 s-1) may lead to liquid bumping in the aperture, and the aqueous solutions may spread out quickly. Signal reproducibility is reasonably good, and relative standard deviation (RSD) for molecular ion signals can be controlled to be smaller than ±15% for consecutive measurements. Measurements at long time intervals (e.g., 60 min) show RSDs of ±40-50%. In addition, the detection limits of formic acid, glycerol, and glutamic acid are estimated to be 0.04%, 0.008%, and 0.002% (weight ratio), respectively.

  18. Selective killing of cancer cells by Ashwagandha leaf extract and its component Withanone involves ROS signaling.

    Directory of Open Access Journals (Sweden)

    Nashi Widodo

    Full Text Available BACKGROUND AND PURPOSE: Ashwagandha is a popular Ayurvedic herb used in Indian traditional home medicine. It has been assigned a variety of health-promoting effects of which the mechanisms remain unknown. We previously reported the selective killing of cancer cells by leaf extract of Ashwagandha (i-Extract and its purified component Withanone. In the present study, we investigated its mechanism by loss-of-function screening (abrogation of i-Extract induced cancer cell killing of the cellular targets and gene pathways. METHODOLOGY/PRINCIPAL FINDINGS: Randomized ribozyme library was introduced into cancer cells prior to the treatment with i-Extract. Ribozymes were recovered from cells that survived the i-Extract treatment. Gene targets of the selected ribozymes (as predicted by database search were analyzed by bioinformatics and pathway analyses. The targets were validated for their role in i-Extract induced selective killing of cancer cells by biochemical and molecular assays. Fifteen gene-targets were identified and were investigated for their role in specific cancer cell killing activity of i-Extract and its two major components (Withaferin A and Withanone by undertaking the shRNA-mediated gene silencing approach. Bioinformatics on the selected gene-targets revealed the involvement of p53, apoptosis and insulin/IGF signaling pathways linked to the ROS signaling. We examined the involvement of ROS-signaling components (ROS levels, DNA damage, mitochondrial structure and membrane potential and demonstrate that the selective killing of cancer cells is mediated by induction of oxidative stress. CONCLUSION: Ashwagandha leaf extract and Withanone cause selective killing of cancer cells by induction of ROS-signaling and hence are potential reagents that could be recruited for ROS-mediated cancer chemotherapy.

  19. The application of selected radionuclides for monitoring of the D-D reactions produced by dense plasma-focus device.

    Science.gov (United States)

    Jednorog, S; Szydlowski, A; Bienkowska, B; Prokopowicz, R

    The dense plasma focus (DPF) device-DPF-1000U which is operated at the Institute of Plasma Physics and Laser Microfusion is the largest that type plasma experiment in the world. The plasma that is formed in large plasma experiments is characterized by vast numbers of parameters. All of them need to be monitored. A neutron activation method occupies a high position among others plasma diagnostic methods. The above method is off-line, remote, and an integrated one. The plasma which has enough temperature to bring about nuclear fusion reactions is always a strong source of neutrons that leave the reactions area and take along energy and important information on plasma parameters and properties as well. Silver as activated material is used as an effective way of neutrons measurement, especially when they are emitted in the form of short pulses like as it happens from the plasma produced in Dense Plasma-Focus devices. Other elements such as beryllium and yttrium are newly introduced and currently tested at the Institute of Plasma Physics and Laser Microfusion to use them in suitable activation neutron detectors. Some specially designed massive indium samples have been recently adopted for angular neutrons distribution measurements (vertical and horizontal) and have been used in the recent plasma experiment conducted on the DPF-1000U device. This choice was substantiated by relatively long half-lives of the neutron induced isotopes and the threshold character of the 115 In(n,n') 115m In nuclear reaction.

  20. Adenosine Selectively Depletes Alloreactive T Cells to Prevent GVHD While Conserving Immunity to Viruses and Leukemia.

    Science.gov (United States)

    Whitehill, Greg D; Amarnath, Shoba; Muranski, Pawel; Keyvanfar, Keyvan; Battiwalla, Minoo; Barrett, Austin J; Chinnassamy, Dhanalakshmi

    2016-09-01

    Selective depletion (SD) of alloreactive T cells from allogeneic hematopoeitic stem cell transplants to prevent graft-versus-host disease (GVHD) without compromising immune reconstitution and antitumor responses remains a challenge. Here, we demonstrate a novel SD strategy whereby alloreacting T cells are efficiently deleted ex vivo with adenosine. SD was achieved in human leukocyte antigen (HLA) mismatched cocultures by multiple exposures to 2 mmol/l adenosine over 7 days. Adenosine depleted greater than to 90% of alloproliferating T cells in mismatched, haploidentical, and matched sibling pairs while conserving response to third-party antigens. Alloreactive CD4 and CD8 T cells were targeted for depletion while NK and B cells were preserved. Our novel approach also preserved nonalloreactive naive, central, and effector memory T-cell subsets, Tregs, and notably preserved T-cell responses against DNA viruses that contribute to transplant related mortality after allogeneic hematopoeitic stem cell transplants. Additionally, T cells recognizing leukemia-associated antigens were efficiently generated in vitro from the cell product post-SD. This study is the first to demonstrate that adenosine depletion of alloactivated T cells maintains a complete immune cell profile and recall viral responses. Expansion of tumor antigen-specific subsets postdepletion opens the possibility of generating T-cell products capable of graft-versus-tumor responses without causing GVHD.

  1. Effects of growth temperature and device structure on GaP solar cells grown by molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Vaisman, M.; Tomasulo, S.; Masuda, T.; Lang, J. R.; Faucher, J.; Lee, M. L. [Department of Electrical Engineering, Yale University, New Haven, Connecticut 06511 (United States)

    2015-02-09

    Gallium phosphide (GaP) is an attractive candidate for wide-bandgap solar cell applications, possessing the largest bandgap of the III-arsenide/phosphides without aluminum. However, GaP cells to date have exhibited poor internal quantum efficiency (IQE), even for photons absorbed by direct transitions, motivating improvements in material quality and device structure. In this work, we investigated GaP solar cells grown by molecular beam epitaxy over a range of substrate temperatures, employing a much thinner emitter than in prior work. Higher growth temperatures yielded the best solar cell characteristics, indicative of increased diffusion lengths. Furthermore, the inclusion of an AlGaP window layer improved both open-circuit voltage and short wavelength IQE.

  2. Granulosa cells and retinoic acid co-treatment enrich potential germ cells from manually selected Oct4-EGFP expressing human embryonic stem cells.

    Science.gov (United States)

    Chen, Hsin-Fu; Jan, Pey-Shynan; Kuo, Hung-Chih; Wu, Fang-Chun; Lan, Chen-Wei; Huang, Mei-Chi; Chien, Chung-Liang; Ho, Hong-Nerng

    2014-09-01

    Differentiation of human embryonic stem (HES) cells to germ cells may become clinically useful in overcoming diseases related to germ-cell development. Niches were used to differentiate HES cell lines, NTU1 and H9 Oct4-enhanced green fluorescence protein (EGFP), including laminin, granulosa cell co-culture or conditioned medium, ovarian stromal cell co-culture or conditioned medium, retinoic acid, stem cell factor (SCF) and BMP4-BMP7-BMP8b treatment. Flow cytometry showed that granulosa cell co-culture (P cells expressing early germ cell marker stage-specific embryonic antigen 1(SSEA1); sorted SSEA1[+] cells did not express higher levels of germ cell gene VASA and GDF9. Manually collected H9 Oct4-EGFP[+] cells expressed significantly higher levels of VASA (P = 0.005) and GDF9 (P = 0.001). H9 Oct4-EGFP[+] cells developed to ovarian follicle-like structures after culture for 28 days but with low efficiency. Unlike SCF and BMP4, retinoic acid co-treatment enhanced VASA, GDF9 and SCP3 expression. A protocol is recommended to enrich differentiated HES cells with germ-cell potential by culture with granulosa cells, conditioned medium or retinoic acid, manual selection of Oct4-EGFP[+] cells, and analysis of VASA, GDF9 expression, or both. Copyright © 2014 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.

  3. SLAMF7-CAR T cells eliminate myeloma and confer selective fratricide of SLAMF7+ normal lymphocytes.

    Science.gov (United States)

    Gogishvili, Tea; Danhof, Sophia; Prommersberger, Sabrina; Rydzek, Julian; Schreder, Martin; Brede, Christian; Einsele, Hermann; Hudecek, Michael

    2017-12-28

    SLAMF7 is under intense investigation as a target for immunotherapy in multiple myeloma. In this study, we redirected the specificity of T cells to SLAMF7 through expression of a chimeric antigen receptor (CAR) derived from the huLuc63 antibody (elotuzumab) and demonstrate that SLAMF7-CAR T cells prepared from patients and healthy donors confer potent antimyeloma reactivity. We confirmed uniform, high-level expression of SLAMF7 on malignant plasma cells in previously untreated and in relapsed/refractory (R/R) myeloma patients who had received previous treatment with proteasome inhibitors and immunomodulatory drugs. Consequently, SLAMF7-CAR T cells conferred rapid cytolysis of previously untreated and R/R primary myeloma cells in vitro. In addition, a single administration of SLAMF7-CAR T cells led to resolution of medullary and extramedullary myeloma manifestations in a murine xenograft model in vivo. SLAMF7 is expressed on a fraction of normal lymphocytes, including subsets of natural killer (NK) cells, T cells, and B cells. After modification with the SLAMF7-CAR, both CD8 + and CD4 + T cells rapidly acquired and maintained a SLAMF7 - phenotype and could be readily expanded to therapeutically relevant cell doses. We analyzed the recognition of normal lymphocytes by SLAMF7-CAR T cells and show that they induce selective fratricide of SLAMF7 +/high NK cells, CD4 + and CD8 + T cells, and B cells. Importantly, however, the fratricide conferred by SLAMF7-CAR T cells spares the SLAMF7 -/low fraction in each cell subset and preserves functional lymphocytes, including virus-specific T cells. In aggregate, our data illustrate the potential use of SLAMF7-CAR T-cell therapy as an effective treatment against multiple myeloma and provide novel insights into the consequences of targeting SLAMF7 for the normal lymphocyte compartment. © 2017 by The American Society of Hematology.

  4. Selective cytotoxicity of indirect nonequilibrium atmospheric pressure plasma against ovarian clear-cell carcinoma.

    Science.gov (United States)

    Utsumi, Fumi; Kajiyama, Hiroaki; Nakamura, Kae; Tanaka, Hiromasa; Hori, Masaru; Kikkawa, Fumitaka

    2014-01-01

    Ovarian clear cell carcinoma (CCC) is a histological type of epithelial ovarian cancer that is less responsive to chemotherapy and associated with a poorer prognosis than serous and endometrioid carcinoma. Non-thermal atmospheric pressure plasma which produces reactive species has recently led to an explosion of research in plasma medicine. Plasma treatment can be applied to cancer treatment to induce apoptosis and tumor growth arrest. Furthermore, recent studies have shown that a medium exposed to plasma also has an anti-proliferative effect against cancer in the absence of direct exposure to plasma. In this study, we confirmed whether this indirect plasma has an anti-tumor effect against CCC, and investigated whether this efficacy is selective for cancer cells. Non-thermal atmospheric pressure plasma induced apoptosis in CCC cells, while human peritoneal mesothelial cells remained viable. Non-thermal atmospheric pressure plasma exhibits selective cytotoxicity against CCC cells which are resistant to chemotherapy.

  5. Cell line selection combined with jasmonic acid elicitation enhance camptothecin production in cell suspension cultures of Ophiorrhiza mungos L.

    Science.gov (United States)

    Deepthi, S; Satheeshkumar, K

    2017-01-01

    Ophiorrhiza mungos is a herbaceous medicinal plant which contains a quinoline alkaloid, camptothecin (CPT), an anticancer compound. A high-yielding cell line, O. mungos cell line-3 (OMC3) was selected from cell suspension cultures of O. mungos using cell aggregate cloning method and established cell suspension culture. OMC3 cell suspension produced significantly high biomass (9.25 ± 1.3 g/flask fresh weight (FW)) and CPT yield (0.095 ± 0.002 mg g -1 dry weight (DW)) compared with the original cell suspension. Inoculum size of OMC3 cell suspension culture was optimised as 14 g L -1 . Media optimisation has shown that 5 % (w/v) sucrose and an increased ammonium/nitrate concentration of 40/20 mM favoured CPT production, whereas 3 % (w/v) sucrose, an ammonium/nitrate concentration of 20/40 mM and 1.25 mM of phosphate favoured biomass accumulation. Jasmonic acid, chitin and salicylic acid was used to elicit CPT production in the original cell suspension culture and achieved significantly high CPT production with jasmonic acid (JA) elicitation. Further, OMC3 cell suspension culture was elicited with JA (50 μM) and obtained 1.12 ± 0.08 mg g -1 DW CPT and 9.52 ± 1.4 g/flask FW (190.4 g L -1 FW). The combination of cell line selection and elicitation has produced 18.66-fold increases in CPT production together with significantly high biomass yield. The study is helpful in the scale-up studies of O. mungos cell suspension culture in suitable bioreactor systems for the production of CPT.

  6. A Small Molecule Inhibitor Selectively Induces Apoptosis in Cells Transformed by High Risk Human Papilloma Viruses.

    Directory of Open Access Journals (Sweden)

    Amy K Sheaffer

    Full Text Available A phenotypic high-throughput cell culture screen was performed to identify compounds that prevented proliferation of the human Papilloma virus type 16 (HPV-16 transformed cell line Ca Ski. A series of quinoxaline compounds exemplified by Compound 1 was identified. Testing against a panel of cell lines demonstrated that Compound 1 selectively inhibited replication of all HPV-16, HPV-18, and HPV-31 transformed cell lines tested with 50% Inhibitory Concentration (IC50 values of 2 to 8 μM relative to IC50 values of 28 to 73 μM in HPV-negative cell lines. Treatment with Compound 1 resulted in a cascade of multiple apoptotic events, including selective activation of effector caspases 3 and 7, fragmentation of cellular DNA, and PARP (poly(ADP-ribose polymerase cleavage in HPV-positive cells relative to HPV-negative cells. Unregulated proliferation of HPV transformed cells is dependent on the viral oncogenes, E6 and E7. Treatment with Compound 1 resulted in a decrease in HPV E7 protein in Ca Ski cells. However, the timing of this reduction relative to other effects of compound treatment suggests that this was a consequence, rather than a cause, of the apoptotic cascade. Likewise, compound treatment resulted in no obvious effects on the E6- and E7- mediated down regulation of p53 and Rb, or their downstream effectors, p21 or PCNA. Further investigation of apoptotic signals induced by Compound 1 revealed cleavage of Caspase-8 in HPV-positive cells as early as 2 hours post-treatment, suggesting the compound initiates apoptosis through the extrinsic, death receptor-mediated, pathway of cell death. These studies provide proof of concept that cells transformed by oncogenic Papillomaviruses can be selectively induced to undergo apoptosis by compound treatment.

  7. A Small Molecule Inhibitor Selectively Induces Apoptosis in Cells Transformed by High Risk Human Papilloma Viruses.

    Science.gov (United States)

    Sheaffer, Amy K; Lee, Min S; Qi, Huilin; Chaniewski, Susan; Zheng, Xiaofan; Farr, Glen A; Esposito, Kim; Harden, David; Lei, Ming; Schweizer, Liang; Friborg, Jacques; Agler, Michele; McPhee, Fiona; Gentles, Robert; Beno, Brett R; Chupak, Lou; Mason, Stephen

    2016-01-01

    A phenotypic high-throughput cell culture screen was performed to identify compounds that prevented proliferation of the human Papilloma virus type 16 (HPV-16) transformed cell line Ca Ski. A series of quinoxaline compounds exemplified by Compound 1 was identified. Testing against a panel of cell lines demonstrated that Compound 1 selectively inhibited replication of all HPV-16, HPV-18, and HPV-31 transformed cell lines tested with 50% Inhibitory Concentration (IC50) values of 2 to 8 μM relative to IC50 values of 28 to 73 μM in HPV-negative cell lines. Treatment with Compound 1 resulted in a cascade of multiple apoptotic events, including selective activation of effector caspases 3 and 7, fragmentation of cellular DNA, and PARP (poly(ADP-ribose) polymerase) cleavage in HPV-positive cells relative to HPV-negative cells. Unregulated proliferation of HPV transformed cells is dependent on the viral oncogenes, E6 and E7. Treatment with Compound 1 resulted in a decrease in HPV E7 protein in Ca Ski cells. However, the timing of this reduction relative to other effects of compound treatment suggests that this was a consequence, rather than a cause, of the apoptotic cascade. Likewise, compound treatment resulted in no obvious effects on the E6- and E7- mediated down regulation of p53 and Rb, or their downstream effectors, p21 or PCNA. Further investigation of apoptotic signals induced by Compound 1 revealed cleavage of Caspase-8 in HPV-positive cells as early as 2 hours post-treatment, suggesting the compound initiates apoptosis through the extrinsic, death receptor-mediated, pathway of cell death. These studies provide proof of concept that cells transformed by oncogenic Papillomaviruses can be selectively induced to undergo apoptosis by compound treatment.

  8. Inferring fitness landscapes and selection on phenotypic states from single-cell genealogical data.

    Directory of Open Access Journals (Sweden)

    Takashi Nozoe

    2017-03-01

    Full Text Available Recent advances in single-cell time-lapse microscopy have revealed non-genetic heterogeneity and temporal fluctuations of cellular phenotypes. While different phenotypic traits such as abundance of growth-related proteins in single cells may have differential effects on the reproductive success of cells, rigorous experimental quantification of this process has remained elusive due to the complexity of single cell physiology within the context of a proliferating population. We introduce and apply a practical empirical method to quantify the fitness landscapes of arbitrary phenotypic traits, using genealogical data in the form of population lineage trees which can include phenotypic data of various kinds. Our inference methodology for fitness landscapes determines how reproductivity is correlated to cellular phenotypes, and provides a natural generalization of bulk growth rate measures for single-cell histories. Using this technique, we quantify the strength of selection acting on different cellular phenotypic traits within populations, which allows us to determine whether a change in population growth is caused by individual cells' response, selection within a population, or by a mixture of these two processes. By applying these methods to single-cell time-lapse data of growing bacterial populations that express a resistance-conferring protein under antibiotic stress, we show how the distributions, fitness landscapes, and selection strength of single-cell phenotypes are affected by the drug. Our work provides a unified and practical framework for quantitative measurements of fitness landscapes and selection strength for any statistical quantities definable on lineages, and thus elucidates the adaptive significance of phenotypic states in time series data. The method is applicable in diverse fields, from single cell biology to stem cell differentiation and viral evolution.

  9. Selective control of human glioma cell proliferation by specific cell interaction.

    Science.gov (United States)

    MacDonald, C M; Freshney, R I; Hart, E; Graham, D I

    1985-01-01

    Cells cultured from anaplastic astrocytoma (Kernohan and Sayre, grades III and IV) will proliferate on confluent monolayers of normal glia, while cells cultured from normal brain will not. The growth of a cell line containing a high proportion of well-differentiated glioma cells (G-CCM) was partially inhibited, though not as much as normal glia, while the growth of a cell line made up of less differentiated cells (G-UVW) was enhanced by the normal glia. Although non-glial confluent monolayers also inhibited the growth of normal glia, this was less specific, as one normal glial line (N-DUT) grew on fibroblasts and intestinal epithelium, although it was unable to do so on normal glia. It is suggested that this may be a useful method for examining reduced density limitation of growth, discriminating between normal and malignant glia, and for separating glioma cells from contaminating normal cells.

  10. Simple processing of back-contacted silicon heterojunction solar cells using selective-area crystalline growth

    KAUST Repository

    Tomasi, Andrea

    2017-04-24

    For crystalline-silicon solar cells, voltages close to the theoretical limit are nowadays readily achievable when using passivating contacts. Conversely, maximal current generation requires the integration of the electron and hole contacts at the back of the solar cell to liberate its front from any shadowing loss. Recently, the world-record efficiency for crystalline-silicon single-junction solar cells was achieved by merging these two approaches in a single device; however, the complexity of fabricating this class of devices raises concerns about their commercial potential. Here we show a contacting method that substantially simplifies the architecture and fabrication of back-contacted silicon solar cells. We exploit the surface-dependent growth of silicon thin films, deposited by plasma processes, to eliminate the patterning of one of the doped carrier-collecting layers. Then, using only one alignment step for electrode definition, we fabricate a proof-of-concept 9-cm2 tunnel-interdigitated back-contact solar cell with a certified conversion efficiency >22.5%.

  11. Selective release of microRNA species from normal and malignant mammary epithelial cells.

    Directory of Open Access Journals (Sweden)

    Lucy Pigati

    2010-10-01

    Full Text Available MicroRNAs (miRNAs in body fluids are candidate diagnostics for a variety of conditions and diseases, including breast cancer. One premise for using extracellular miRNAs to diagnose disease is the notion that the abundance of the miRNAs in body fluids reflects their abundance in the abnormal cells causing the disease. As a result, the search for such diagnostics in body fluids has focused on miRNAs that are abundant in the cells of origin. Here we report that released miRNAs do not necessarily reflect the abundance of miRNA in the cell of origin. We find that release of miRNAs from cells into blood, milk and ductal fluids is selective and that the selection of released miRNAs may correlate with malignancy. In particular, the bulk of miR-451 and miR-1246 produced by malignant mammary epithelial cells was released, but the majority of these miRNAs produced by non-malignant mammary epithelial cells was retained. Our findings suggest the existence of a cellular selection mechanism for miRNA release and indicate that the extracellular and cellular miRNA profiles differ. This selective release of miRNAs is an important consideration for the identification of circulating miRNAs as biomarkers of disease.

  12. The Natural Selection of Herpesviruses and Virus-Specific NK Cell Receptors

    Directory of Open Access Journals (Sweden)

    Joseph C. Sun

    2009-10-01

    Full Text Available During the co-evolution of cytomegalovirus (CMV and natural killer (NK cells, each has evolved specific tactics in an attempt to prevail. CMV has evolved multiple immune evasion mechanisms to avoid detection by NK cells and other immune cells, leading to chronic infection. Meanwhile, the host has evolved virus-specific receptors to counter these evasion strategies. The natural selection of viral genes and host receptors allows us to observe a unique molecular example of "survival of the fittest", as virus and immune cells try to out-maneuver one another or for the virus to achieve détente for optimal dissemination in the population.

  13. Cell Culture Methods for the Selection of Osteoblast-Like Cells from the Periodontal Ligament

    Science.gov (United States)

    1998-05-01

    Periodontal regenerative therapy involves restoration of lost periodontal architecture through the coordinated efforts of fibroblasts, osteoblasts...and cementoblasts. The periodontal ligament plays an important role in this process because it is thought to contribute necessary progenitor cells for...regeneration. Numerous reports indicate phenotypic heterogeneity among cells of the periodontal ligament. In addition to populations of cells

  14. CD34+ (Non-Malignant) Stem Cell Selection for Patients Receiving Allogeneic Stem Cell Transplantation

    Science.gov (United States)

    2017-07-13

    Bone Marrow Failure Syndrome; Severe Aplastic Anemia; Severe Congenital Neutropenia; Amegakaryocytic Thrombocytopenia; Diamond-Blackfan Anemia; Schwachman Diamond Syndrome; Primary Immunodeficiency Syndromes; Acquired Immunodeficiency Syndromes; Histiocytic Syndrome; Familial Hemophagocytic Lymphocytosis; Lymphohistiocytosis; Macrophage Activation Syndrome; Langerhans Cell Histiocytosis (LCH); Hemoglobinopathies; Sickle Cell Disease; Sickle Cell-beta-thalassemia

  15. Low-cost, high-efficiency organic/inorganic hetero-junction hybrid solar cells for next generation photovoltaic device

    Science.gov (United States)

    Pudasaini, P. R.; Ayon, A. A.

    2013-12-01

    Organic/inorganic hybrid structures are considered innovative alternatives for the next generation of low-cost photovoltaic devices because they combine advantages of the purely organic and inorganic versions. Here, we report an efficient hybrid solar cell based on sub-wavelength silicon nanotexturization in combination with the spin-coating of poly (3,4-ethylene-dioxythiophene):polystyrenesulfonate (PEDOT:PSS). The described devices were analyzed by collecting current-voltage and capacitance-voltage measurements in order to explore the organic/inorganic heterojunction properties. ALD deposited ultrathin aluminium oxide was used as a junction passivation layer between the nanotextured silicon surface and the organic polymer. The measured interface defect density of the device was observed to decrease with the inclusion of an ultrathin Al2O3 passivation layer leading to an improved electrical performance. This effect is thought to be ascribed to the suppression of charge recombination at the organic/inorganic interface. A maximum power conversion efficiency in excess of 10% has been achieved for the optimized geometry of the device, in spite of lacking an antireflection layer or back surface field enhancement schemes.

  16. Characterization of size-dependent mechanical properties of tip-growing cells using a lab-on-chip device.

    Science.gov (United States)

    Hu, Chengzhi; Munglani, Gautam; Vogler, Hannes; Ndinyanka Fabrice, Tohnyui; Shamsudhin, Naveen; Wittel, Falk K; Ringli, Christoph; Grossniklaus, Ueli; Herrmann, Hans J; Nelson, Bradley J

    2016-12-20

    Quantification of mechanical properties of tissues, living cells, and cellular components is crucial for the modeling of plant developmental processes such as mechanotransduction. Pollen tubes are tip-growing cells that provide an ideal system to study the mechanical properties at the single cell level. In this article, a lab-on-a-chip (LOC) device is developed to quantitatively measure the biomechanical properties of lily (Lilium longiflorum) pollen tubes. A single pollen tube is fixed inside the microfluidic chip at a specific orientation and subjected to compression by a soft membrane. By comparing the deformation of the pollen tube at a given external load (compressibility) and the effect of turgor pressure on the tube diameter (stretch ratio) with finite element modeling, its mechanical properties are determined. The turgor pressure and wall stiffness of the pollen tubes are found to decrease considerably with increasing initial diameter of the pollen tubes. This observation supports the hypothesis that tip-growth is regulated by a delicate balance between turgor pressure and wall stiffness. The LOC device is modular and adaptable to a variety of cells that exhibit tip-growth, allowing for the straightforward measurement of mechanical properties.

  17. Gene Editing in Human Lymphoid Cells: Role for Donor DNA, Type of Genomic Nuclease and Cell Selection Method

    Directory of Open Access Journals (Sweden)

    Anastasia Zotova

    2017-11-01

    Full Text Available Programmable endonucleases introduce DNA breaks at specific sites, which are repaired by non-homologous end joining (NHEJ or homology recombination (HDR. Genome editing in human lymphoid cells is challenging as these difficult-to-transfect cells may also inefficiently repair DNA by HDR. Here, we estimated efficiencies and dynamics of knockout (KO and knockin (KI generation in human T and B cell lines depending on repair template, target loci and types of genomic endonucleases. Using zinc finger nuclease (ZFN, we have engineered Jurkat and CEM cells with the 8.2 kb human immunodeficiency virus type 1 (HIV-1 ∆Env genome integrated at the adeno-associated virus integration site 1 (AAVS1 locus that stably produce virus particles and mediate infection upon transfection with helper vectors. Knockouts generated by ZFN or clustered regularly interspaced short palindromic repeats (CRISPR/Cas9 double nicking techniques were comparably efficient in lymphoid cells. However, unlike polyclonal sorted cells, gene-edited cells selected by cloning exerted tremendous deviations in functionality as estimated by replication of HIV-1 and human T cell leukemia virus type 1 (HTLV-1 in these cells. Notably, the recently reported high-fidelity eCas9 1.1 when combined to the nickase mutation displayed gene-dependent decrease in on-target activity. Thus, the balance between off-target effects and on-target efficiency of nucleases, as well as choice of the optimal method of edited cell selection should be taken into account for proper gene function validation in lymphoid cells.

  18. Systems, methods and computer-readable media for modeling cell performance fade of rechargeable electrochemical devices

    Science.gov (United States)

    Gering, Kevin L

    2013-08-27

    A system includes an electrochemical cell, monitoring hardware, and a computing system. The monitoring hardware periodically samples performance characteristics of the electrochemical cell. The computing system determines cell information from the performance characteristics of the electrochemical cell. The computing system also develops a mechanistic level model of the electrochemical cell to determine performance fade characteristics of the electrochemical cell and analyzing the mechanistic level model to estimate performance fade characteristics over aging of a similar electrochemical cell. The mechanistic level model uses first constant-current pulses applied to the electrochemical cell at a first aging period and at three or more current values bracketing a first exchange current density. The mechanistic level model also is based on second constant-current pulses applied to the electrochemical cell at a second aging period and at three or more current values bracketing the second exchange current density.

  19. Stem cell selection in vivo using foamy vectors cures canine pyruvate kinase deficiency.

    Directory of Open Access Journals (Sweden)

    Grant D Trobridge

    Full Text Available Hematopoietic stem cell (HSC gene therapy has cured immunodeficiencies including X-linked severe combined immunodeficiency (SCID-X1 and adenine deaminase deficiency (ADA. For these immunodeficiencies corrected cells have a selective advantage in vivo, and low numbers of gene-modified cells are sufficient to provide therapeutic benefit. Strategies to efficiently transduce and/or expand long-term repopulating cells in vivo are needed for treatment of diseases that require higher levels of corrected cells, such as hemoglobinopathies. Here we expanded corrected stem cells in vivo in a canine model of a severe erythroid disease, pyruvate kinase deficiency.We used a foamy virus (FV vector expressing the P140K mutant of methylguanine methyltransferase (MGMTP140K for in vivo expansion of corrected hematopoietic repopulating cells. FV vectors are attractive gene transfer vectors for hematopoietic stem cell gene therapy since they efficiently transduce repopulating cells and may be safer than more commonly used gammaretroviral vectors. Following transplantation with HSCs transduced ex vivo using a tri-cistronic FV vector that expressed EGFP, R-type pyruvate kinase, and MGMTP140K, we were able to increase marking from approximately 3.5% to 33% in myeloid long-term repopulating cells resulting in a functional cure.Here we describe in one affected dog a functional cure for a severe erythroid disease using stem cell selection in vivo. In addition to providing a potential cure for patients with pyruvate kinase deficiency, in vivo selection using foamy vectors with MGMTP140K has broad potential for several hematopoietic diseases including hemoglobinopathies.

  20. Differentiation and selection of hepatocyte precursors in suspension spheroid culture of transgenic murine embryonic stem cells.

    Directory of Open Access Journals (Sweden)

    Elke Gabriel

    Full Text Available Embryonic stem cell-derived hepatocyte precursor cells represent a promising model for clinical transplantations to diseased livers, as well as for establishment of in vitro systems for drug metabolism and toxicology investigations. This study aimed to establish an in vitro culture system for scalable generation of hepatic progenitor cells. We used stable transgenic clones of murine embryonic stem cells possessing a reporter/selection vector, in which the enhanced green fluorescent protein- and puromycin N-acetyltransferase-coding genes are driven by a common alpha-fetoprotein gene promoter. This allowed for "live" monitoring and puromycin selection of the desired differentiating cell type possessing the activated alpha-fetoprotein gene. A rotary culture system was established, sequentially yielding initially partially selected hepatocyte lineage-committed cells, and finally, a highly purified cell population maintained as a dynamic suspension spheroid culture, which progressively developed the hepatic gene expression phenotype. The latter was confirmed by quantitative RT-PCR analysis, which showed a progressive up-regulation of hepatic genes during spheroid culture, indicating development of a mixed hepatocyte precursor-/fetal hepatocyte-like cell population. Adherent spheroids gave rise to advanced differentiated hepatocyte-like cells expressing hepatic proteins such as albumin, alpha-1-antitrypsin, cytokeratin 18, E-cadherin, and liver-specific organic anion transporter 1, as demonstrated by fluorescent immunostaining. A fraction of adherent cells was capable of glycogen storage and of reversible up-take of indocyanine green, demonstrating their hepatocyte-like functionality. Moreover, after transplantation of spheroids into the mouse liver, the spheroid-derived cells integrated into recipient. These results demonstrate that large-scale hepatocyte precursor-/hepatocyte-like cultures can be established for use in clinical trials, as well as in

  1. Microfluidic device for the detection of glucose using a micro direct methanol fuel cell as an amperometric detection power source.

    Science.gov (United States)

    Ito, Takeshi; Kunimatsu, Masayuki; Kaneko, Satoru; Ohya, Seishiro; Suzuki, Koji

    2007-02-15

    We designed and prepared a novel microbiosensing system consisting of a microbioreactor fabricated using photosensitive sheets intercalated between Pyrex wafers as a dam structure, together with a micro fuel cell as a power source device between the electrodes for amperometric detection. The dam structure retains enzyme (glucose oxidase, GOx)-immobilized microbeads in a microchannel. Microelectrodes are used as an integrated detector within a microchannel located downstream of the dam structure, and these are used to detect the oxidation current of hydrogen peroxide produced from a glucose sample and GOx. A micro direct methanol fuel cell (mu-DMFC, i.d. 500 microm) was fabricated on a polymeric substrate and was used to supply a potential for the electrochemical detector. In this case, two mu-DMFCs were stacked on one substrate to increase the voltage for the oxidation of hydrogen peroxide. A linear response curve was obtained in range from 0.1 to 10 mM glucose for the designed microbiosensing system. These results show that a microfluidic biosensing system designed with a mu-DMFC device is useful and has the potential to assist minuaturization and simplification of the sensing system, in addition to increasing disposability of the device.

  2. Hydrogen Passivation of Interstitial Zn Defects in Heteroepitaxial InP Cell Structures and Influence on Device Characteristics

    Science.gov (United States)

    Ringel, S. A.; Chatterjee, B.

    2004-01-01

    Hydrogen passivation of heteroepitaxial InP solar cells is of recent interest for deactivation of dislocations and other defects caused by the cell/substrate lattice mismatch that currently limit the photovoltaic performance of these devices. In this paper we present strong evidence that, in addition to direct hydrogen-dislocation interactions, hydrogen forms complexes with the high concentration of interstitial Zn defects present within the p(+) Zn-doped emitter of MOCVD-grown heteroepitaxial InP devices, resulting in a dramatic increase of the forward bias turn-on voltage by as much as 280 mV, from 680 mV to 960 mV. This shift is reproducible and thermally reversible and no such effect is observed for either n(+)p structures or homoepitaxial p(+)n structures grown under identical conditions. A combination of photoluminescence (PL), electrochemical C-V dopant profiling, SIMS and I-V measurements were performed on a set of samples having undergone a matrix of hydrogenation and post-hydrogenation annealing conditions to investigate the source of this voltage enhancement and confirm the expected role of interstitial Zn and hydrogen. A precise correlation between all measurements is demonstrated which indicates that Zn interstitials within the p(+) emitter and their interaction with hydrogen are indeed responsible for this device behavior.

  3. CD8 T cells express randomly selected KIRs with distinct specificities compared with NK cells

    Science.gov (United States)

    Béziat, Vivien; Cichocki, Frank; Liu, Lisa L.; Levine, Jeffrey; Larsson, Stella; Koup, Richard A.; Anderson, Stephen K.; Ljunggren, Hans-Gustaf

    2012-01-01

    Epistatic interactions between killer cell immunoglobulin-like receptors (KIRs) and their cognate HLA class I ligands have important implications for reproductive success, antiviral immunity, susceptibility to autoimmune conditions and cancer, as well as for graft-versus-leukemia reactions in settings of allogeneic stem cell transplantation. Although CD8 T cells are known to acquire KIRs when maturing from naive to terminally differentiated cells, little information is available about the constitution of KIR repertoires on human CD8 T cells. Here, we have performed a high-resolution analysis of KIR expression on CD8 T cells. The results show that most CD8 T cells possess a restricted KIR expression pattern, often dominated by a single activating or inhibitory KIR. Furthermore, the expression of KIR, and its modulation of CD8 T-cell function, was independent of expression of self-HLA class I ligands. Finally, despite similarities in the stochastic regulation of KIRs by the bidirectional proximal promoter, the specificity of inhibitory KIRs on CD8 T cells was often distinct from that of natural killer cells in the same individual. The results provide new insight into the formation of KIR repertoires on human T cells. PMID:22968455

  4. Clinical Efficacy of Selective Focal Ablation by Navigable Percutaneous Disc Decompression Device in Patients With Cervical Herniated Nucleus Pulposus.

    Science.gov (United States)

    Kim, Sung Hoon; Lee, Sang-Heon; Kim, Nack Hwan; Kim, Min Hyun; Park, Hyeun Jun; Jung, Yong Jin; Yoo, Hyun-Joon; Meng, Won Jun; Kim, Victoria

    2017-02-01

    To evaluate the clinical efficacy and safety following percutaneous disc decompression, using navigable disc decompression device for cervical herniated nucleus pulposus (HNP). Twenty subjects diagnosed with cervical HNP and refractory to conservative management were enrolled for the study. The herniated discs were decompressed under fluoroscopic guidance, using radiofrequency ablation device with navigable wand. The sagittal and axial plain magnetic resonance images of the clinically significant herniated disc, decided the space between the herniated base and outline as the target area for ablation. Clinical outcome was determined by Numeric Rating Scale (NRS), Neck Disability Index (NDI), and Bodily Pain scale of Short Form-36 (SF-36 BP), assessed after 48 weeks. After the procedure, we structurally matched the magnetic resonance imaging (MRI) and C-arm images through bony markers. The wand position was defined as being 'correct' if the tip was placed within the target area of both AP and lateral views; if not, the position was stated as 'incorrect'. The average NRS fell from 7 to 1 at 48 weeks post procedure (p<0.05). In addition, statistically significant improvement was noted in the NDI and SF-36BP (p<0.05). The location of the wand tip resulted in 16 correct and 4 incorrect placements. Post-48 weeks, 3 of the incorrect tip cases and 1 correct tip case showed unsuccessful outcomes. The study demonstrated the promising results and safety of the procedure. Thus, focal plasma ablation of cervical HNP with navigable wand can be another effective treatment option.

  5. Physical Characteristics of Medical Textile Prostheses Designed for Hernia Repair: A Comprehensive Analysis of Select Commercial Devices

    Directory of Open Access Journals (Sweden)

    Linli Miao

    2015-12-01

    Full Text Available Inguinal hernia repairs are among the most frequent operations performed worldwide. This study aims to provide further understanding of structural characteristics of hernia prostheses, and better comprehensive evaluation. Weight, porosity, pore size and other physical characteristics were evaluated; warp knitting structures were thoroughly discussed. Two methods referring to ISO 7198:1998, i.e., weight method and area method, were employed to calculate porosity. Porosity ranged from 37.3% to 69.7% measured by the area method, and 81.1% to 89.6% by the weight method. Devices with two-guide bar structures displayed both higher porosity (57.7%–69.7% and effective porosity (30.8%–60.1% than single-guide bar structure (37.3%–62.4% and 0%–5.9%, respectively. Filament diameter, stitch density and loop structure combined determined the thickness, weight and characteristics of pores. They must be well designed to avoid zero effective porosity regarding a single-bar structure. The area method was more effective in characterizing flat sheet meshes while the weight method was perhaps more accurate in describing stereoscopic void space for 3D structure devices. This article will give instructive clues for engineers to improve mesh structures, and better understanding of warp knitting meshes for surgeons.

  6. Genetic selection system allowing monitoring of myofibrillogenesis in living cardiomyocytes derived from mouse embryonic stem cells

    Directory of Open Access Journals (Sweden)

    R Bugorsky

    2009-08-01

    Full Text Available Embryonic stem (ES cell-derived cardiomyocytes recapitulate cardiomyogenesis in vitro and are a potential source of cells for cardiac repair. However, this requires enrichment of mixed populations of differentiating ES cells into cardiomyocytes. Toward this goal, we have generated bicistronic vectors that express both the blasticidin S deaminase (bsd gene and a fusion protein consisting of either myosin light chain (MLC-3f or human a-actinin 2A and enhanced green fluorescent protein (EGFP under the transcriptional control of the a-cardiac myosin heavy chain (a-MHC promoter. Insertion of the DNase I-hypersensitive site (HS-2 element from the b-globin locus control region, which has been shown to reduce transgene silencing in other cell systems, upstream of the transgene promoter enhanced MLC3f-EGFP gene expression levels in mouse ES cell lines. The a-MHC-a- actinin-EGFP, but not the a-MHC-MLC3f-EGFP, construct resulted in the correct incorporation of the newly synthesized fusion protein at the Z-band of the sarcomeres in ES cellderived cardiomyocytes. Exposure of embryoid bodies to blasticidin S selected for a relatively pure population of cardiomyocytes within 3 days. Myofibrillogenesis could be monitored by fluorescence microscopy in living cells due to sarcomeric epitope tagging. Therefore, this genetic system permits the rapid selection of a relatively pure population of developing cardiomyocytes from a heterogeneous population of differentiating ES cells, simultaneously allowing monitoring of early myofibrillogenesis in the selected myocytes.

  7. In vitro assessment of antiproliferative action selectivity of dietary isothiocyanates for tumor versus normal human cells

    Directory of Open Access Journals (Sweden)

    Konić-Ristić Aleksandra

    2016-01-01

    Full Text Available Background/Aim. Numerous epidemiological studies have shown beneficial effects of cruciferous vegetables consumption in cancer chemoprevention. Biologically active compounds of different Brassicaceae species with antitumor potential are isothiocyanates, present in the form of their precursors - glucosinolates. The aim of this study was to determine the selectivity of antiproliferative action of dietary isothiocyanates for malignant versus normal cells. Methods. Antiproliferative activity of three isothiocyanates abundant in human diet: sulforaphane, benzyl isothiocyanate (BITC and phenylethyl isothiocyanate, on human cervix carcinoma cell line - HeLa, melanoma cell line - Fem-x, and colon cancer cell line - LS 174, and on peripheral blood mononuclear cells (PBMC, with or without mitogen, were determined by MTT colorimetric assay 72 h after their continuous action. Results. All investigated isothiocyanates inhibited the proliferation of HeLa, Fem-x and LS 174 cells. On all cell lines treated, BITC was the most potent inhibitor of cell proliferation with half-maximum inhibitory concentration (IC50 values of 5.04 mmoL m-3 on HeLa cells, 2.76 mmol m-3 on Fem-x, and 14.30 mmol m-3 on LS 174 cells. Antiproliferative effects on human PBMC were with higher IC50 than on malignant cells. Indexes of selectivity, calculated as a ratio between IC50 values obtained on PBMC and malignant cells, were between 1.12 and 16.57, with the highest values obtained for the action of BITC on melanoma Fem-x cells. Conclusion. Based on its antiproliferative effects on malignant cells, as well as the selectivity of the action to malignant vs normal cells, benzyl isothiocyanate can be considered as a promising candidate in cancer chemoprevention. In general, the safety of investigated compounds, in addition to their antitumor potential, should be considered as an important criterion in cancer chemoprevention. Screening of selectivity is a plausible approach to the evaluation

  8. Inferring fitness landscapes and selection on phenotypic states from single-cell genealogical data

    Science.gov (United States)

    Kussell, Edo

    2017-01-01

    Recent advances in single-cell time-lapse microscopy have revealed non-genetic heterogeneity and temporal fluctuations of cellular phenotypes. While different phenotypic traits such as abundance of growth-related proteins in single cells may have differential effects on the reproductive success of cells, rigorous experimental quantification of this process has remained elusive due to the complexity of single cell physiology within the context of a proliferating population. We introduce and apply a practical empirical method to quantify the fitness landscapes of arbitrary phenotypic traits, using genealogical data in the form of population lineage trees which can include phenotypic data of various kinds. Our inference methodology for fitness landscapes determines how reproductivity is correlated to cellular phenotypes, and provides a natural generalization of bulk growth rate measures for single-cell histories. Using this technique, we quantify the strength of selection acting on different cellular phenotypic traits within populations, which allows us to determine whether a change in population growth is caused by individual cells’ response, selection within a population, or by a mixture of these two processes. By applying these methods to single-cell time-lapse data of growing bacterial populations that express a resistance-conferring protein under antibiotic stress, we show how the distributions, fitness landscapes, and selection strength of single-cell phenotypes are affected by the drug. Our work provides a unified and practical framework for quantitative measurements of fitness landscapes and selection strength for any statistical quantities definable on lineages, and thus elucidates the adaptive significance of phenotypic states in time series data. The method is applicable in diverse fields, from single cell biology to stem cell differentiation and viral evolution. PMID:28267748

  9. Low-dose IL-2 selectively activates subsets of CD4+ Tregs and NK cells

    Science.gov (United States)

    Hirakawa, Masahiro; Matos, Tiago; Liu, Hongye; Koreth, John; Kim, Haesook T.; Paul, Nicole E.; Murase, Kazuyuki; Whangbo, Jennifer; Alho, Ana C.; Nikiforow, Sarah; Cutler, Corey; Ho, Vincent T.; Armand, Philippe; Alyea, Edwin P.; Antin, Joseph H.; Blazar, Bruce R.; Lacerda, Joao F.; Soiffer, Robert J.

    2016-01-01

    CD4+ regulatory T cells (CD4Tregs) play a critical role in the maintenance of immune tolerance and prevention of chronic graft-versus-host disease (GVHD) after allogeneic hematopoietic stem cell transplantation. IL-2 supports the proliferation and survival of CD4Tregs and previous studies have demonstrated that IL-2 induces selective expansion of CD4Tregs and improves clinical manifestations of chronic GVHD. However, mechanisms for selective activation of CD4Tregs and the effects of low-dose IL-2 on other immune cells are not well understood. Using mass cytometry, we demonstrate that low concentrations of IL-2 selectively induce STAT5 phosphorylation in Helios+ CD4Tregs and CD56brightCD16– NK cells in vitro. Preferential activation and expansion of Helios+ CD4Tregs and CD56brightCD16– NK cells was also demonstrated in patients with chronic GVHD receiving low-dose IL-2. With prolonged IL-2 treatment for 48 weeks, phenotypic changes were also observed in Helios– CD4Tregs. The effects of low-dose IL-2 therapy on conventional CD4+ T cells and CD8+ T cells were limited to increased expression of PD-1 on effector memory T cells. These studies reveal the selective effects of low-dose IL-2 therapy on Helios+ CD4Tregs and CD56bright NK cells that constitutively express high-affinity IL-2 receptors as well as the indirect effects of prolonged exposure to low concentrations of IL-2 in vivo. PMID:27812545

  10. Selective cytotoxicity of Aniba rosaeodora essential oil towards epidermoid cancer cells through induction of apoptosis.

    Science.gov (United States)

    Sœur, Jérémie; Marrot, Laurent; Perez, Philippe; Iraqui, Ismail; Kienda, Guy; Dardalhon, Michèle; Meunier, Jean-Roch; Averbeck, Dietrich; Huang, Meng-Er

    2011-01-10

    Essential oils are complex mixtures of odorous and volatile compounds derived from secondary plant metabolism. They can be isolated from many plants by mechanical pressing or hydro- and steam-distillation and are known to induce a wide range of biological effects through their antibacterial, antifungal, cytotoxic, antioxidant and antimutagenic activities. In order to explore their beneficial properties on human skin cells, we investigated the effects of an essential oil from rosewood Aniba rosaeodora (REO) on the human epidermoid carcinoma cell line A431, on immortal HaCaT cells thought to represent an early stage of skin carcinogenesis, on transformed normal HEK001 keratinocytes and on primary normal NHEK keratinocytes. In a defined range of concentrations, REO selectively killed A431 and HaCaT cells. The same treatments had only a minor cytotoxic effect on HEK001 and NHEK cells. Preferentially in A431 and HaCaT cells, REO triggered the production of reactive oxygen species, induced depolarization of the mitochondrial membrane and caused caspase-dependent cell death characterized by phosphatidylserine externalization, an early marker of apoptosis. Both intrinsic and extrinsic apoptotic pathways were implicated in REO-induced cell death. The identification of selective induction of apoptosis in precancerous and cancerous skin cells by REO highlights the potential anticancer activity of this essential oil. 2010 Elsevier B.V. All rights reserved.

  11. Effect of gold nanoparticles on thermal gradient generation and thermotaxis of E. coli cells in microfluidic device.

    Science.gov (United States)

    Murugesan, Nithya; Panda, Tapobrata; Das, Sarit K

    2016-08-01

    Bacteria responds to changing chemical and thermal environment by moving towards or away from a particular location. In this report, we looked into thermal gradient generation and response of E. coli DH5α cells to thermal gradient in the presence and in the absence of spherical gold nanoparticles (size: 15 to 22 nm) in a static microfluidic environment using a polydimethylsiloxane (PDMS) made microfluidic device. A PDMS-agarose based microfluidic device for generating thermal gradient has been developed and the thermal gradient generation in the device has been validated with the numerical simulation. Our studies revealed that the presence of gold nanoparticles, AuNPs (0.649 μg/mL) has no effect on the thermal gradient generation. The E. coli DH5α cells have been treated with AuNPs of two different concentrations (0.649 μg/mL and 0.008 μg/mL). The thermotaxis behavior of cells in the presence of AuNPs has been studied and compared to the thermotaxis of E.coli DH5α cells in the absence of AuNPs. In case of thermotaxis, in the absence of the AuNPs, the E. coli DH5α cells showed better thermotaxis towards lower temperature range, whereas in the presence of AuNPs (0.649 μg/mL and 0.008 μg/mL) thermotaxis of the E. coli DH5α cells has been inhibited. The results show that the spherical AuNPs intervenes in the themotaxis of E. coli DH5α cells and inhibits the cell migration. The reason for the failure in thermotaxis response mechanism may be due to decreased F-type ATP synthase activity and collapse of membrane potential by AuNPs, which, in turn, leads to decreased ATP levels. This has been hypothesized since both thermotaxis and chemotaxis follows the same response mechanism for migration in which ATP plays critical role.

  12. Evaluation of three levels of selective devices relevant to management of the Danish Kattegat-Skagerrak Nephrops fishery

    DEFF Research Database (Denmark)

    Frandsen, Rikke; Holst, René; Madsen, Niels

    2009-01-01

    parameters by species and confidence bands to compare the selective properties of different gear types. For cod, haddock, hake, Nephrops, plaice, and whiting we obtained estimates for all three gear variants, whereas we obtained estimates for lemon sole and witch only with the standard and the SMP codends......This study illuminates a range of technological options relevant to present legislation for regulating fish by-catch in a small-meshed Nephrops fishery. The selection of cod, haddock, hake, lemon sole, Nephrops, plaice, saithe, witch, and whiting were evaluated using the twin-trawl technique for...

  13. Selection of radioresistant tumor cells and presence of ALDH1 activity in vitro

    International Nuclear Information System (INIS)

    Mihatsch, Julia; Toulany, Mahmoud; Bareiss, Petra M.; Grimm, Sabrina; Lengerke, Claudia; Kehlbach, Rainer; Rodemann, H. Peter

    2011-01-01

    Background: Tumor resistance to radiotherapy has been hypothesized to be mediated by a tumor subpopulation, called cancer stem cells (CSCs). Based on the proposed function of CSCs in radioresistance, we explored the cancer stem cell properties of cells selected for radioresistance phenotype. Materials and methods: A549 and SK-BR-3 cells were radioselected with four single doses of 4 or 3 Gy in intervals of 10-12 days and used for colony formation assay and γ-H2AX foci formation assay. Expression of putative stem cell markers, i.e. Sox2, Oct4, ALDH1, and CD133 were analyzed using Western blotting. A549 and SK-BR-3 cells sorted based on their ALDH1 activity were analyzed in clonogenic survival assays. Results: Radioselected A549 and SK-BR-3 cells (A549-R, SK-BR-3-R) showed increased radioresistance and A549-R cells presented enhanced repair of DNA-double strand breaks. PI3K inhibition significantly reduced radioresistance of A549-R cells. Cell line specific differences in the expression of the putative CSC markers Sox2 and Oct4 were observed when parental and radioselected cells were compared but could not be directly correlated to the radioresistant phenotype. However, enzyme activity of the putative stem cell marker ALDH1 showed a correlation to radioresistance. Conclusions: Subpopulations of pooled radioresistant colonies, selected by various radiation exposures were analyzed for the presence of putative stem cell markers. Although the pattern of Sox2, Oct4, and CD133 expression was not generally associated with radioresistance, presence of ALDH1 seems to be indicative for subpopulations with increased radioresistance.

  14. The characterisation of selective proton damage on GaAs solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Aliyu, Y.H. (School of Electrical, Electronic and Systems Engineering, Wales Univ., Cardiff (United Kingdom)); Morgan, D.V. (School of Electrical, Electronic and Systems Engineering, Wales Univ., Cardiff (United Kingdom)); Bunce, R.W. (School of Electrical, Electronic and Systems Engineering, Wales Univ., Cardiff (United Kingdom))

    1993-01-16

    Selective ion bombardment damage was induced on n/n[sup +] GaAs Schottky barrier solar cell structure using several proton energies and doses. The damage in the surface, interface, and the bulk regions were characterised by I-V, C-V, and thermally stimulated current technique (TSC). A correlation between the selective damages and the nature of the defects and their location was obtained. (orig.)

  15. Application of Thermoelectric Devices to Fuel Cell Power Generation: Demonstration and Evaluation

    Science.gov (United States)

    2004-09-01

    significant potential for improving the security of electrical power sup- plied by using on-site power generation. On-site, distributed power generation can...of temperatures where TE devices op- erate optimally. Besides the central and distributed power generation capability of solar power stations, TE

  16. Kaempferol nanoparticles achieve strong and selective inhibition of ovarian cancer cell viability

    Science.gov (United States)

    Luo, Haitao; Jiang, Bingbing; Li, Bingyun; Li, Zhaoliang; Jiang, Bing-Hua; Chen, Yi Charlie

    2012-01-01

    Ovarian cancer is one of the leading causes of cancer death for women throughout the Western world. Kaempferol, a natural flavonoid, has shown promise in the chemoprevention of ovarian cancer. A common concern about using dietary supplements for chemoprevention is their bioavailability. Nanoparticles have shown promise in increasing the bioavailability of some chemicals. Here we developed five different types of nanoparticles incorporating kaempferol and tested their efficacy in the inhibition of viability of cancerous and normal ovarian cells. We found that positively charged nanoparticle formulations did not lead to a significant reduction in cancer cell viability, whereas nonionic polymeric nanoparticles resulted in enhanced reduction of cancer cell viability. Among the nonionic polymeric nanoparticles, poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) nanoparticles incorporating kaempferol led to significant reduction in cell viability of both cancerous and normal cells. Poly(DL-lactic acid-co-glycolic acid) (PLGA) nanoparticles incorporating kaempferol resulted in enhanced reduction of cancer cell viability together with no significant reduction in cell viability of normal cells compared with kaempferol alone. Therefore, both PEO-PPO-PEO and PLGA nanoparticle formulations were effective in reducing cancer cell viability, while PLGA nanoparticles incorporating kaempferol had selective toxicity against cancer cells and normal cells. A PLGA nanoparticle formulation could be advantageous in the prevention and treatment of ovarian cancers. On the other hand, PEO-PPO-PEO nanoparticles incorporating kaempferol were more effective inhibitors of cancer cells, but they also significantly reduced the viability of normal cells. PEO-PPO-PEO nanoparticles incorporating kaempferol may be suitable as a cancer-targeting strategy, which could limit the effects of the nanoparticles on normal cells while retaining their potency against cancer cells. We

  17. Tipping the balance: robustness of tip cell selection, migration and fusion in angiogenesis.

    Directory of Open Access Journals (Sweden)

    Katie Bentley

    2009-10-01

    Full Text Available Vascular abnormalities contribute to many diseases such as cancer and diabetic retinopathy. In angiogenesis new blood vessels, headed by a migrating tip cell, sprout from pre-existing vessels in response to signals, e.g., vascular endothelial growth factor (VEGF. Tip cells meet and fuse (anastomosis to form blood-flow supporting loops. Tip cell selection is achieved by Dll4-Notch mediated lateral inhibition resulting, under normal conditions, in an interleaved arrangement of tip and non-migrating stalk cells. Previously, we showed that the increased VEGF levels found in many diseases can cause the delayed negative feedback of lateral inhibition to produce abnormal oscillations of tip/stalk cell fates. Here we describe the development and implementation of a novel physics-based hierarchical agent model, tightly coupled to in vivo data, to explore the system dynamics as perpetual lateral inhibition combines with tip cell migration and fusion. We explore the tipping point between normal and abnormal sprouting as VEGF increases. A novel filopodia-adhesion driven migration mechanism is presented and validated against in vivo data. Due to the unique feature of ongoing lateral inhibition, 'stabilised' tip/stalk cell patterns show sensitivity to the formation of new cell-cell junctions during fusion: we predict cell fates can reverse. The fusing tip cells become inhibited and neighbouring stalk cells flip fate, recursively providing new tip cells. Junction size emerges as a key factor in establishing a stable tip/stalk pattern. Cell-cell junctions elongate as tip cells migrate, which is shown to provide positive feedback to lateral inhibition, causing it to be more susceptible to pathological oscillations. Importantly, down-regulation of the migratory pathway alone is shown to be sufficient to rescue the sprouting system from oscillation and restore stability. Thus we suggest the use of migration inhibitors as therapeutic agents for vascular

  18. A preliminary study for constructing a bioartificial liver device with induced pluripotent stem cell-derived hepatocytes

    Directory of Open Access Journals (Sweden)

    Iwamuro Masaya

    2012-12-01

    Full Text Available Abstract Background Bioartificial liver systems, designed to support patients with liver failure, are composed of bioreactors and functional hepatocytes. Immunological rejection of the embedded hepatocytes by the host immune system is a serious concern that crucially degrades the performance of the device. Induced pluripotent stem (iPS cells are considered a desirable source for bioartificial liver systems, because patient-derived iPS cells are free from immunological rejection. The purpose of this paper was to test the feasibility of a bioartificial liver system with iPS cell-derived hepatocyte-like cells. Methods Mouse iPS cells were differentiated into hepatocyte-like cells by a multi-step differentiation protocol via embryoid bodies and definitive endoderm. Differentiation of iPS cells was evaluated by morphology, PCR assay, and functional assays. iPS cell-derived hepatocyte-like cells were cultured in a bioreactor module with a pore size of 0.2 μm for 7 days. The amount of albumin secreted into the circulating medium was analyzed by ELISA. Additionally, after a 7-day culture in a bioreactor module, cells were observed by a scanning electron microscope. Results At the final stage of the differentiation program, iPS cells changed their morphology to a polygonal shape with two nucleoli and enriched cytoplasmic granules. Transmission electron microscope analysis revealed their polygonal shape, glycogen deposition in the cytoplasm, microvilli on their surfaces, and a duct-like arrangement. PCR analysis showed increased expression of albumin mRNA over the course of the differentiation program. Albumin and urea production was also observed. iPS-Heps culture in bioreactor modules showed the accumulation of albumin in the medium for up to 7 days. Scanning electron microscopy revealed the attachment of cell clusters to the hollow fibers of the module. These results indicated that iPS cells were differentiated into hepatocyte-like cells after culture

  19. Cell-Specific Cre Recombinase Expression Allows Selective Ablation of Glutamate Receptors from Mouse Horizontal Cells

    Science.gov (United States)

    Janssen-Bienhold, Ulrike; Schultz, Konrad; Cimiotti, Kerstin; Weiler, Reto; Willecke, Klaus; Dedek, Karin

    2013-01-01

    In the mouse retina, horizontal cells form an electrically coupled network and provide feedback signals to photoreceptors and feedforward signals to bipolar cells. Thereby, horizontal cells contribute to gain control at the first visual synapse and to the antagonistic organization of bipolar and ganglion cell receptive fields. However, the nature of horizontal cell output remains a matter of debate, just as the exact contribution of horizontal cells to center-surround antagonism. To facilitate studying horizontal cell function, we developed a knockin mouse line which allows ablating genes exclusively in horizontal cells. This knockin line expresses a Cre recombinase under the promoter of connexin57 (Cx57), a gap junction protein only expressed in horizontal cells. Consistently, in Cx57+/Cre mice, Cre recombinase is expressed in almost all horizontal cells (>99%) and no other retinal neurons. To test Cre activity, we crossbred Cx57+/Cre mice with a mouse line in which exon 11 of the coding sequence for the ionotropic glutamate receptor subunit GluA4 was flanked by two loxP sites (GluA4fl/fl). In GluA4fl/fl:Cx57+/Cre mice, GluA4 immunoreactivity was significantly reduced (∼50%) in the outer retina where horizontal cells receive photoreceptor inputs, confirming the functionality of the Cre/loxP system. Whole-cell patch-clamp recordings from isolated horizontal cell somata showed a reduction of glutamate-induced inward currents by ∼75%, suggesting that the GluA4 subunit plays a major role in mediating photoreceptor inputs. The persistent current in GluA4-deficient cells is mostly driven by AMPA and to a very small extent by kainate receptors as revealed by application of the AMPA receptor antagonist GYKI52466 and concanavalin A, a potentiator of kainate receptor-mediated currents. In summary, the Cx57+/Cre mouse line provides a versatile tool for studying horizontal cell function. GluA4fl/fl:Cx57+/Cre mice, in which horizontal cells receive less excitatory input

  20. Selection and syntheses of tentacle type peptides as 'artificial' lectins against various cell-surface carbohydrates.

    Science.gov (United States)

    Hyun, Soonsil; Kim, Jiyoung; Kwon, Miyun; Yu, Jaehoon

    2007-01-01

    Sialyl Lewis X and its derivatives are cell-surface carbohydrates that are involved in cell-cell recognition by carbohydrate-mediated interactions. Unfortunately, owing to the similarities between carbohydrates only a limited number of tools are available for their differentiation. In this study, we prepared a selected phage-displayed peptide library against LeX (2), SLN (3), or LN (4), which compared to sLeX (1) lack sialic acid, fucose, and both sialic acid and fucose from constituents, respectively. Sequences of the selected peptides, prepared as tentacle type dimeric peptides, were prepared and shown to have micromolar affinities for the cognate carbohydrates. The specificities displayed by these 'artificial' lectins overwhelm those of natural lectins. These results suggest that they can serve as useful tools to detect changes in the terminal monosaccharide of cell-surface carbohydrates.

  1. A simple optical fiber device for quantitative fluorescence microscopy of single living cells

    NARCIS (Netherlands)

    van Graft, M.; van Graft, Marja; Oosterhuis, B.; Oosterhuis, Bernard; van der Werf, Kees; de Grooth, B.G.; Greve, Jan

    1993-01-01

    simple and relatively inexpensive system is described for obtaining quantitative fluorescence measurements on single living cells loaded with a fluorescent probe to study cell physiological processes. The light emitted from the fluorescent cells is captured by and transported through an optical

  2. Size effect on organic optoelectronics devices: Example of photovoltaic cell efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, A.K. [PPF Cellules solaires photovoltaiques plastiques, Laboratoire POMA, UMR-CNRS 6136, Universite d' Angers, 2 Bd Lavoisier, 49045 Angers (France); Nunzi, J.M. [PPF Cellules solaires photovoltaiques plastiques, Laboratoire POMA, UMR-CNRS 6136, Universite d' Angers, 2 Bd Lavoisier, 49045 Angers (France); Departments of Chemistry and Physics at Queen' s University, Kingston K7L 3N6, Ontario (Canada)], E-mail: nunjijm@queensu.ca; Ratier, B. [XLim Institute of research, UMR-CNRS 6172, Faculte des Sciences de l' Universite de Limoges, 123 Avenue Albert Thomas, 87060 Limoges (France); Moliton, A. [XLim Institute of research, UMR-CNRS 6172, Faculte des Sciences de l' Universite de Limoges, 123 Avenue Albert Thomas, 87060 Limoges (France)], E-mail: andre.moliton@unilim.fr

    2008-02-18

    Electromagnetic study of organic photovoltaic cells design shows that electrical parameters depend drastically on the active area geometry: we theoretically show that electrical parameters are altered when the cell length becomes greater than one centimeter. Experimental verification is provided with simple molecular heterojunction cells with areas from 0.03 to 0.78 cm{sup 2}.

  3. AN EFFICIENT CELL SELECTION IN CELLULAR NETWORK WITH BETTER SCALABILITY AND RE-ROUTING

    Directory of Open Access Journals (Sweden)

    KARTHIKEYAN A.

    2014-11-01

    Full Text Available This paper mainly concentrate about Cell selection strategy and Re-Routing process in the Cellular Network. Cell selection is the process of deciding the cell to provide services to every mobile station. After the mobile user or mobile station make a call, then nearby base station will allocate space for that particular call through base station controller. The ultimate aim is to find a maximum-profit subset of clients that can be fully satisfied by All-or-Nothing Demand Maximization algorithm (AoNDM .Efficiency can be improved by Global Cell Selection mechanism. One of the important aspects of mobility management is mobility – ability to access service at anywhere, anyhow and anytime. The Edmonds–Karp algorithm is utilized to provide maximum flow from source to destination and deals the capacity of base station. For Re-Routing a predictive approach is used, where a Mcall is pre-established to potential new base stations by setting up a multicast tree with neighbouring base stations as leaf nodes. This Predictive approach reduces the latency caused by re-routing is in considerable level with strict time constraints. An extensive simulation study demonstrating the benefits of using our algorithms in high-loaded capacityconstrained of future 4G networks .Specifically, our algorithms obtain better usage of the network’s capacity, in comparison with the current cell selection algorithms and provide better results.

  4. Custom-made titanium devices as membranes for bone augmentation in implant treatment: Modeling accuracy of titanium products constructed with selective laser melting.

    Science.gov (United States)

    Otawa, Naruto; Sumida, Tomoki; Kitagaki, Hisashi; Sasaki, Kiyoyuki; Fujibayashi, Shunsuke; Takemoto, Mitsuru; Nakamura, Takashi; Yamada, Tomohiro; Mori, Yoshihide; Matsushita, Tomiharu

    2015-09-01

    The purpose of this study was to verify the modeling accuracy of various products, and to produce custom-made devices for bone augmentation in individual patients requiring implantation. Two-(2D) and three-dimensional (3D) specimens and custom-made devices that were designed as membranes for guided bone regeneration (GBR) were produced using a computer-aided design (CAD) and rapid prototyping (RP) method. The CAD design was produced using a 3D printing machine and selective laser melting (SLM) with pure titanium (Ti) powder. The modeling accuracy was evaluated with regard to: the dimensional accuracy of the 2D and 3D specimens; the accuracy of pore structure of the 2D specimens; the accuracy of porosity of the 3D specimens; and the error between CAD design and the scanned real product by overlapped images. The accuracy of the 2D and 3D specimens indicated precise results in various parameters, which were tolerant in ISO 2768-1. The error of overlapped images between the CAD and scanned data indicated that accuracy was sufficient for GBR. In integrating area of all devices, the maximum and average error were 292 and 139 μm, respectively. High modeling accuracy can be achieved in various products using the CAD/RP-SLM method. These results suggest the possibility of clinical applications. Copyright © 2015 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

  5. Multiple Myeloma Tumor Cells are Selectively Killed by Pharmacologically-dosed Ascorbic Acid.

    Science.gov (United States)

    Xia, Jiliang; Xu, Hongwei; Zhang, Xiaoyan; Allamargot, Chantal; Coleman, Kristen L; Nessler, Randy; Frech, Ivana; Tricot, Guido; Zhan, Fenghuang

    2017-04-01

    High-dose chemotherapies to treat multiple myeloma (MM) can be life-threatening due to toxicities to normal cells and there is a need to target only tumor cells and/or lower standard drug dosage without losing efficacy. We show that pharmacologically-dosed ascorbic acid (PAA), in the presence of iron, leads to the formation of highly reactive oxygen species (ROS) resulting in cell death. PAA selectively kills CD138 + MM tumor cells derived from MM and smoldering MM (SMM) but not from monoclonal gammopathy undetermined significance (MGUS) patients. PAA alone or in combination with melphalan inhibits tumor formation in MM xenograft mice. This study shows PAA efficacy on primary cancer cells and cell lines in vitro and in vivo. Copyright © 2017 The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc. Published by Elsevier B.V. All rights reserved.

  6. Multiple Myeloma Tumor Cells are Selectively Killed by Pharmacologically-dosed Ascorbic Acid

    Directory of Open Access Journals (Sweden)

    Jiliang Xia

    2017-04-01

    Full Text Available High-dose chemotherapies to treat multiple myeloma (MM can be life-threatening due to toxicities to normal cells and there is a need to target only tumor cells and/or lower standard drug dosage without losing efficacy. We show that pharmacologically-dosed ascorbic acid (PAA, in the presence of iron, leads to the formation of highly reactive oxygen species (ROS resulting in cell death. PAA selectively kills CD138+ MM tumor cells derived from MM and smoldering MM (SMM but not from monoclonal gammopathy undetermined significance (MGUS patients. PAA alone or in combination with melphalan inhibits tumor formation in MM xenograft mice. This study shows PAA efficacy on primary cancer cells and cell lines in vitro and in vivo.

  7. Spectroelectrochemical Sensing Based on Multimode Selectivity simultaneously Achievable in a Single Device. 11. Design and Evaluation of a Small Portable Sensor for the Determination of Ferrocyanide in Hanford Waste Samples

    International Nuclear Information System (INIS)

    Stegemiller, Michael L.; Heineman, William R.; Seliskar, Carl J.; Ridgway, Thomas H.; Bryan, Samuel A.; Hubler, Timothy L.; Sell, Richard L.

    2003-01-01

    Spectroelectrochemical sensing based on multimode selectivity simultaneously achievable in a single device. 11. Design and evaluation of a small portable sensor for the determination of ferrocyanide in Hanford waste samples

  8. Rapid selection and proliferation of CD133+ cells from cancer cell lines: chemotherapeutic implications.

    Directory of Open Access Journals (Sweden)

    Sarah E Kelly

    2010-04-01

    Full Text Available Cancer stem cells (CSCs are considered a subset of the bulk tumor responsible for initiating and maintaining the disease. Several surface cellular markers have been recently used to identify CSCs. Among those is CD133, which is expressed by hematopoietic progenitor cells as well as embryonic stem cells and various cancers. We have recently isolated and cultured CD133 positive [CD133+] cells from various cancer cell lines using a NASA developed Hydrodynamic Focusing Biore