bluuebunny/crossref_metadata_2025_split huggingface dataset:
CuInS2/PEDOT Photovoltaic Structure
Authors: Bereznev Sergei , Konovalov Igor , Kois Julia , Mellikov Enn , Öpik Andres 
Published: June 2019

AbstractStructures based on combination of electrically conductive polymers with inorganic semiconductors are currently intensively investigated with the aim to prepare low-cost, largearea and flexible photovoltaic devices. In this study, multilayer structures consisting of CuInS2 (CIS) and poly(3,4-ethylenedioxythiophene) (PEDOT) doped with polystyrenesulfonate (PSS) thin films were prepared and investigated for photovoltaic applications. Polycrystalline CIS absorber layers were synthesized on top of a layered structure on Cu tape substrate using socalled non-vacuum CISCuT technique. Thin PEDOT buffer layers doped with PSS were deposited onto KCN etched and vacuum annealed CIS films. The deposition was performed using the spin-casting technique from an aqueous dispersion of PEDOT/PSS mixed with Nmethylpyrrolidone, isopropanol, glycerin and epoxysilane additives. Optimal deposition parameters for stable PEDOT films with a good adherence to the surface of CIS were selected experimentally. The morphology and thickness of prepared films and structures was determined using SEM technique. Average film thickness was about of 1.5 μm for CIS and 50 nm for PEDOT films. Current-voltage and impedance characteristics were measured. Significant photovoltage and photocurrent of the photovoltaic structures were observed under standard illumination intensity. The best structure showed an open-circuit voltage of 510 mV and a shortcircuit current density of 20.2 mA/cm2.
Structural and Spectroscopic Study of Langmuir-Schäfer Films of Bis Zn-Ethane-Bridged Porphyrins Dimer
Authors: Panzera G. , Conoci S. , Coffa S. , Pignataro B. , Sortino S. , Valli L. , Borovkov V.V. , Inoue Y. 
Published: June 2019

AbstractThin films (1-24 layers) of bis-zinc ethane-bridged porphyrin dimer (1) have been transferred on solid surfaces, by the Langmuir- Schäfer (LS) horizontal method. The related surface pressurearea isotherm curve shows that in dependence of the film pressure different condensed phases may occur in the monolayer. The inspection of the monolayer by Brewster Angle Microscopy (BAM) reveals the presence of peculiar networks whose structural features seemingly change upon film compression. On the other hand, the Scanning Force Microscopy (SFM) analysis performed on LS films shows fractal networks constituted by nanoscopic supramolecular aggregates, whose shape and size depend again on the LS deposition surface pressure. Finally, also UV-vis spectroscopy measurements indicates that the absorption is almost linearly related to the film thickness that is directly connected to the surface pressure.
Synthesis of a Zero-Birefringence Optical Polymer by the Birefringent Crystal DopantMethod
Authors: Ohkita Hisanori , Mukoh Masaki , Tagaya Akihiro , Koike Yasuhiro 
Published: June 2019

AbstractBirefringence induced by the orientation of polymer main chains during an injectionmolding or extrusion processing restricts the application of optical polymers to optical devices that require maintaining the polarization state of incident light. We propose the “birefringent crystal dopant method” to compensate the birefringence of polymers by homogeneous doping with an opposite birefringent needle-like crystal. Strontium carbonate (SrCO3) was selected for this method and synthesized, with particle lengths of 50-200nm and aspect ratios of 2-5. SrCO3 was doped into poly(MMA/BzMA= 78/22(wt./wt.)) film. The film was uniaxially drawn at 130°C and 4mm/min. For the first time, the positive birefringence of the drawn copolymer film at a wavelength of 633nm was compensated by doping with 0.3wt.% of SrCO3 without losing transparency and thermostability.
Spontaneous Orientation of Alq3 Molecule in Evaporated Film and Its Vanishment by Light Irradiation
Authors: Sugi Keiji , Ishii Hisao , Kimura Yasuo , Niwano Michio , Hayashi Naoki , Ouchi Yukio , Ito Eisuke , Seki Kazuhiko 
Published: June 2019

AbstractRecently we found high and persistent spontaneous buildup of the surface potential upon vacuum vapor deposition of tris(8-hydroxyquinolinato) aluminum(III)(Alq3) on Au substrate under dark conditions (28 V for 560 nm thick Alq3 film). Such giant potential is removed by visible-light irradiation. These natures of the film suggest the possible applications to various organic devices such as memory devices. In this study, we investigated the retention time of the giant potential and the mechanism of the light-induced depolarization in order to discuss the feasibility of the device applications. The observed decay rate of the surface potential in vacuum condition was roughly 10 % loss in 10 years, which is enough for memory devices. As to the decay rate by light-irradiation, the observed rate was successfully reproduced by a theoretical simulation based on the photo-induced randomization of oriented Alq3 molecules.
New Liquid Crystalline Semiconductors And Their Fabrication in Organic Field Effect Transistor Devices
Authors: Heeney Martin , Graham David , Shkunov Maxim , Sparrowe David , Giles Mark , Bailey Clare 
Published: June 2019

AbstractThe performance of the semiconducting component in organic field effect transistors (OFET's), is a key parameter in the advancement of organic electronic devices. This work describes the development of solution processible liquid crystalline semiconductors, both main chain rigid rod polymers and small molecule polymerisable liquid crystals, referred to as reactive mesogens. New conjugated main chain polymeric semiconductors have been designed, synthesised, and their performance in transistor devices is reported. Small molecule liquid crystalline semiconductors, which contain reactive end groups, were also prepared, and their design, characterisation, and performance in transistor devices is discussed.
Semiconductor Quantum Dots for Multicolor Fluorescence Imaging and Spectroscopy of Single Cancer Cells
Authors: Gao Xiaohu , Nie Shuming , Coulter Wallace H. 
Published: June 2019

AbstractLuminescent quantum dots (QDs) are emerging as a new class of biological labels with unique properties and applications that are not available from traditional organic dyes and fluorescent proteins. Here we report new developments in using semiconductor quantum dots for quantitative imaging and spectroscopy of single cancer cells. We show that both live and fixed cells can be labeled with multicolor QDs, and that single cells can be analyzed by fluorescence imaging and wavelength-resolved spectroscopy. These results raise new possibilities in cancer imaging, molecular profiling, and disease staging.
Large Area, High Aspect Ratio Microelectrode Arrays
Authors: Merritt Charles D. , Falkenstein Paul L. , Justus Brian L. 
Published: June 2019

AbstractA method is described for the fabrication of arrays of conducting, high aspect-ratio microwires for use as electrodes. The electrode arrays are fabricated by electrochemical deposition of metals, including Ni, Pt, Ag, Au and Rh, in channel glass templates having parallel, uniform, hollow channels with diameters that range from sub-micrometer to over 100 micrometers. The metals completely fill the hollow channels, yielding highly uniform electrodes with aspect ratios on the order of 1000 or more. The glass template electrically insulates the electrodes from one another. The electrode array wafers are cut and polished to a thickness ranging from about 100 to 2000 micrometers. The overall surface area is as large as 1 square centimeter. Alternatively, the wafers can be partially etched with acid to remove some of the glass matrix surrounding the electrodes, exposing an array of bare, solid wire stubs. The high aspect ratio microelectrode arrays were initially fabricated in order to provide the electrical interface for an intraocular retinal prosthesis, but have additional applications including biological and chemical sensing. Arrays with different channel sizes, different electrode spacing (with pitch from approximately 3R to 20R, where R is the electrode radius), and different geometrical arrangement are presented.
Ultrananocrystalline Diamond-Biomolecular Composites: Towards BioMEMS
Authors: Grynaviski N. M. Haralampus , Auciello O. , Carlisle J. A. , Gerbi J. E. , Gruen D. M. , Moore J. F. , Zinovev A. , Firestone M. A. 
Published: June 2019

AbstractThe surface functionalization of ultrananocrystalline (UNCD) thin films has been investigated to develop biocomposite materials for use as BioMicroElectroMechanical Systems (BioMEMS). Specifically, hydrophobic, hydrogen-terminated UNCD films have been synthesized using a microwave plasma chemical vapor deposition technique then surface functionalized using a two-step modification procedure. This procedure produces a mixed submonolayer comprised of chloro- and hydroxyl- terminated alkyl chains chemisorbed to the UNCD surface. This surface modification procedure serves to provide functional groups that will allow for the subsequent attachment of a wide variety of biological macromolecules (e.g., proteins, biomembranes) and the ability to tune the hydrophilic nature of the diamond. The resultant materials have been characterized using surface-sensitive spectroscopies (NEXAFS and XPS).
Effects of Single-Walled Carbon Nanotube on Polymerase Chain Reaction
Authors: Cui Daxiang , Tian Furong , Kong Yong , Ozkan Cengiz S. , Titushikin Igor , Gao Huajian 
Published: June 2019

AbstractPolymerase Chain Reaction (PCR) is a complicated gene amplification process using Mg2+ as an assistant factor of Taq enzyme. Influence of single-walled carbon nanotube on that reaction was investigated with scanning electron microscope (SEM), transmission electron microscope TEM) and quantitative PCR product analysis. Results showed that adding single-walled carbon nanotubes in the reaction liquid with a concentration of less than 3 νg/νl increase the amounts of PCR products. But more carbon nanotubes cause a great reduction of the PCR products. Similar effects were observed in the reaction without Mg2+. Possible reason could be the aggregation of reaction components caused by small amount of additive carbon nanotubes, which increases reaction probability. Our observations suggest that small amount of carbon nanotube could be used as an assistant factor to improve the PCR reaction.
Electric Field-Assisted Positioning of Neurons on Pt Microelectrode Arrays
Authors: Prasad Shalini , Yang Mo , Zhang Xuan , Ni Yingchun , Parpura Vladimir , Ozkan Cengiz. S. , Ozkan Mihrimah 
Published: June 2019

AbstractCharacterization of electrical activity of individual neurons is the fundamental step in understanding the functioning of the nervous system. Single cell electrical activity at various stages of cell development is essential to accurately determine in in-vivo conditions the position of a cell based on the procured electrical activity. Understanding memory formation and development translates to changes in the electrical activity of individual neurons. Hence, there is an enormous need to develop novel ways for isolating and positioning individual neurons over single recording sites. To this end, we used a 3x3 multiple microelectrode array system to spatially arrange neurons by applying a gradient AC field. We characterized the electric field distribution inside our test platform by using two dimensiona l finite element modeling (FEM) and determined the location of neurons over the electrode array. Dielectrophoretic AC fields were utilized to separate the neurons from the glial cells and to position the neurons over the electrodes. The neurons were obtained from 0-2-day-old rat (Sprague-Dawley) pups. The technique of using electric fields to achieve single neuron patterning has implications in neural engineering, elucidating a new and simpler method to develop and study neuronal activity as compared to conventional microelectrode array techniques.
Use of Flexible Materials with a Novel Pressure Driven Equibiaxial Cell Stretching Device for Mechanical Stimulation of Single Mammalian Cells
Authors: Kubicek James D. , Brelsford Stephanie , LeDuc Philip R. 
Published: June 2019

AbstractMechanical stimulation of single cells has been shown to affect cellular behavior from the molecular scale to ultimate cell fate including apoptosis and proliferation. In this, the ability to control the spatiotemporal application of force on cells through their extracellular matrix connections is critical to understand the cellular response of mechanotransduction. Here, we develop and utilize a novel pressure-driven equibiaxial cell stretching device (PECS) combined with an elastomeric material to control specifically the mechanical stimulation on single cells. Cells were cultured on silicone membranes coated with molecular matrices and then a uniform pressure was introduced to the opposite surface of the membrane to stretch single cells equibiaxially. This allowed us to apply mechanical deformation to investigate the complex nature of cell shape and structure. These results will enhance our knowledge of cellular and molecular function as well as provide insights into fields including biomechanics, tissue engineering, and drug discovery.
Optimization of Biosensing Microcantilever Devices
Authors: Zhang Xuan , Yang Mo , Ozkan Cengiz S. 
Published: June 2019

AbstractOptimization of piezoresistive microcantilevers for biosensing applications has been studied using finite element analysis. Models have been described for predicting the static behavior of cantilevers with elastic and piezoresistive layers for analyte-receptor binding. The high-sensitivity cantilevers can be used to detect changes in surface stress due to the binding and hybridization of biomolecules. Chemo-mechanical binding forces have been analyzed to understand the issues of saturation over the cantilever surface. The introduction of stress concentration regions during cantilever fabrication has also been discussed which enhances the detection sensitivity through increased surface stress.
Micromachined magnetic ultrasound transducer in post-processed CMOS
Authors: Viswanathan Rohit , Jankowski Nicholas , Lye Whye-Kei , Dufrenoy Gregory Petit , Harrison Michael J. , Hossack John A. , Blalock Travis N. , Reed Michael L. 
Published: June 2019

AbstractThis paper presents a novel MEMS Ultrasound Electro-Magnetic transducer. With advances in CMOS MEMS fabrication processes [2] we can explore and build miniature devices which could only be designed till a few years back. As our understanding in MEMS evolved, we explored the use of Electro-Magnetism as an effective way to produce ultrasound waves. Thus we can use a highly efficient and inexpensive fabrication technique to fabricate transducers with a fairly good capability to produce and detect ultrasound waves.The transducer consists of 2 concentric spiral coils, one carrying an AC current (which is tethered to the substrate at one end and free to vibrate at the other, also called the “Flapper”) and other coil carrying DC current (enveloping the inner coil, fixed and called “Stator”). The force arising from the interaction of the coupled magnetic fields induces a mechanical vibration of the flapper structure. The transducer serves as an actuator or a sensor (where we simply apply a pressure force on the flapper and note the frequency response of the flapper).The current mode helps to associate the transducer with front-end electronics, which is one of the most critical components of ultrasound imaging systemsAdvantages of this approach as compared to traditional PZT ceramics and capacitative micromachined devices are explored.Different dimensions of the transducer to accommodate the limitations in the processes are explored and a comparison of the parameters is presented.Potential uses and future challenges are discussed.
Combinatorial Peptide Libraries for Selecting Inorganic-Binding Proteins: A Step in Molecular Biomimetics
Authors: Tamerler C. , Dinçer S. , Heidel D. , Karagûler N. , Sarikaya M. 
Published: June 2019

AbstractProteins, one of the building blocks in organisms, not only control the assembly in biological systems but also provide most of their complex functions. It may be possible to assemble materials for practical technological applications utilizing the unique advantages provided by proteins. Here we discuss molecular biomimetic pathways in the quest for imitating biology at the molecular scale via protein engineering. We use combinatorial biology protocols to select short polypeptides that have affinity to inorganic materials and use them in assembling novel hybrid materials. We give an overview of some of the recent developments of molecular engineering towards this goal. Inorganic surface specific proteins were identified by using cell surface and phage display technologies. Examples of metal and metal oxide specific polypeptides were represented with an emphasis on certain level of specificities. The recognition and self assembling characteristics of these inorganic-binding proteins would be employed in develeopment of hybrid multifunctional materials for novel bio- and nano-technological applications.
Modelling Carbon Nanotube Based Bio-Nano Systems: A Molecular Dynamics Study
Authors: Kong Yong , Cui Daxiang , Ozkan Cengiz S. , Gao Huajian 
Published: June 2019

AbstractMolecular dynamics simulations were performed to study dynamics of carbon nanotube (CNT) interacting with biological molecules (DNA oligonucleotide and protein polypeptide) in an aqueous environment. Our results showed that an oligonucleotide or a polypeptide could be spontaneously inserted into a CNT, provided that the tube size is large enough and the oligonucleotide/polypeptide is appropriately aligned with CNT. The van der Waals and hydrophobic forces were found to be important for the insertion process, with the former playing a more dominant role in the CNT-oligonucleotide and CNT-polypeptide interaction. We discussed temperature effect on the filling process and found that higher temperature can accelerate encapsulation of biological molecules. Our study has general implications on filling nanoporous materials with water solutes of molecular cluster or nanoparticles. The encapsulated CNT-oligonucleotide/polypeptide or other CNT based bio-nano-complex can be further exploited for applications such as molecular electronics, sensors, electronic DNA sequencing, and nanotechnology of gene/drug delivery systems.
Bio-Inspired Morphogens and Biomimetic Biomaterials for Regenerative Medicine
Authors: Reddi A. Hari 
Published: June 2019

AbstractRegenerative medicine is the science of design and manufacture of parts for functional restoration of damaged tissues due to cancer, disease and trauma. Morphogenesis is the developmental cascade of pattern formation, body plan establishment and differentiation of tissues culminating in adult form. Regeneration in general, recapitulates in parts, embryonic morphogenesis. Thus, the principles of morphogenesis can be applied to tissue engineering for regenerative medicine and surgery. The threekey ingredients for tissue engineering and regenerative medicine are inductive morphogens, responding stem cells, and extracellular matrix materials. Therefore bioactive morphogens can be integrated into materials for functional restoration by tissue engineering. A morphogen is a morphogenetic protein signal that acts on responding stem cells. Bone morphogenesis is induced by bone morphogenetic proteins (BMPs). BMPs play a role in pattern formation, cell differentiation, maintenance and regeneration of tissues. BMPs are pleiotropic and act on chemotaxis, mitosis and differentiation of progenitor stem cells. There are nearly twenty BMPs in the human genome. BMPs have actions beyond bone in development of teeth, heart, kidney, eye, skin, and brain. Thus, BMPs may be called body morphogenetic proteins. Stem cells are primordial cells with unlimited replicative potential and can be programmed by morphogens such as BMPs. Extracellular matrix is the native scaffolding material that can be used to deliver morphogens such as BMPs for tissue engineering of bone. Biomimetic materials are typically synthetic, polymeric structures that mimic extracellular matrix scaffolding by presenting the cellular binding sites found within collagens, fibronectin, proteoglycans and glycoproteins. Materials that mimic extracellular matrix scaffolding such as BMPs bind to collagens I&IV, heparan sulfate and heparin. BMPs bound to collagen acts as a composite biomaterial to initiate bone formation and the shape can be molded by an appropriate template. In addition to including BMPs in a carrier matrix, the geometry of the carrier matrix is critical for optimal tissue engineering. For example: collagen particles smaller than 44μm are feeble in bone induction compared to the coarse (420μm) particles. Gene therapy approaches using genes for morphogenesis such as BMPs allows a sustained, prolonged secretion of gene products. Thus, morphogens integrated into biomaterials may be useful in regenerative medicine.
Carbon Nanofiber Surface Roughness Increases Osteoblast Adhesion
Authors: Ellison Karen S. , Price Rachel L. , Haberstroh Karen M. , Webster Thomas J. 
Published: June 2019

AbstractThe present study demonstrated for the first time desirable cytocompatibility properties of carbon nanofibers pertinent for bone prosthetic applications. Specifically, osteoblast (boneforming cells), fibroblast (cells contributing to callus formation and fibrous encapsulation events that result in implant loosening), chondrocyte (cartilage-forming cells), and smooth muscle cell (for comparison purposes) adhesion were determined on carbon nanofibers in the present in vitro study. Results provided evidence that nanometer dimension carbon fibers promoted select osteoblast adhesion, in contrast to the performance of conventional carbon fibers. Moreover, adhesion of other cells was not influenced by carbon fiber dimensions. To determine properties that selectively enhanced osteoblast adhesion, similar cell adhesion assays were performed on poly-lactic-co-glycolic (PLGA) casts of carbon fiber compacts previously tested. Compared to PLGA casts of conventional carbon fibers, results provided the first evidence of enhanced select osteoblast adhesion on PLGA casts of nanophase carbon fibers. The summation of these results demonstrate that due to a high degree of nanometer surface roughness, carbon fibers and PLGA with nanometer surface dimensions may be optimal materials to selectively increase osteoblast adhesion necessary for successful orthopedic implant applications.
Development of Elastic Protein-based Polymers as Materials for Acoustic Absorption
Authors: Urry Dan W. , Xu J. , Wang Weijun , Hayes Larry , Prochazka Frederic , Parker Timothy M. 
Published: June 2019

AbstractElastic protein-based polymers comprised of repeating pentapeptide sequences, (GXGXP)n, exhibit mechanical resonances that have been observed to date with frequency maxima near 5 MHz and 3 kHz. Because the 3 kHz resonance is in the middle of the acoustic frequency range, the purpose here is to substantiate the relevance of the 3 kHz resonance to acoustic absorption and to demonstrate means of improving mechanical properties for the sound absorption application. Previously reported loss factor data in the 100 Hz to 10 kHz range is substantiated by relevant but distinctly different measurements of loss shear modulus and loss permittivity. Furthermore cross-linking approaches are reported that result in increased elastic moduli by an order of magnitude to 4 × 106 Pa at 20% strain and increased break stress by two orders of magnitude to 1.3 × 107 Pa while exhibiting break stain values of several hundred per cent.