bluuebunny/crossref_metadata_2025_split huggingface dataset:
Growth of Erbium Doped PbF2 - SrF2 Epitaxial Layers on GaAs(111)B for Upconversion Waveguide Laser Applications
Authors: Lui M. , McFarlane R. A. , Yap D. 
Published: May 2017

AbstractWaveguide structures offer the possibility of making an upconversion laser operating at room temperature. By reducing the optical mode cross section can lead to a very high pump power density which allows modest pumping powers to overcome non-radiative decay processes. We have reported earlier on the observation of upconversion luminescence from both planar and channel waveguides of Erbium doped ZnF2 on MgF2(001) and Erbium doped PbF2 on GaAs(100). The epitaxial fluoride layers were all grown by Molecular Beam Epitaxy. Fluoride films preferentially grow on the (111) GaAs surface. In order to exploit this fact, we have grown Erbium doped PbF2 on GaAs(111)B with an intervening SrF2 cladding layer. The SrF2 and PbF2 growth conditions have been optimized on GaAs(111)B using X-ray rocking curve analysis. The crystalline quality of the films grown on GaAs(111)B are far superior to those grown on GaAs(100). Upconversion luminescence has been observed in the PbF2: Er/SrF2/GaAs(111)B planar waveguide structures. The guide ends were formed by cleaving the semiconductor wafer and the 800nm and 980nm pump light was introduced from a Ti-Sapphire laser by end pumping using a microscope objective.
Material and Spectroscopic Properties of Cr in Different Oxidation States in Calcium Fluorapatite
Authors: Gruber J. B. , Hutchinson J. A. , Harris D. C. , Seltzer M. D. , Allik T. H. , Morrison C. A. , Scripsick M. P. 
Published: May 2017

AbstractThe material and spectroscopic properties of Cr-doped Ca5(PO4)3F (FAP) were investigated using several different chemical and physical means. From analytical titration measurements the chromium in Cr:FAP was found to be tetravalent. ESR measurements detected a trace (0.5 - 10 ppm) of Cr5+ (3d1) and no evidence for Cr3+ (3d3). The absorption and emission spectra of Cr: FAP can be interpreted on the basis of Cr4+ (3d2) ions substituting for P within a distorted tetrahedron of oxygen ions. Calculated electronic (Stark) levels for Cr4+ based on an approximate site symmetry of C4 agree well with levels deduced from an analysis of the experimental optical data. The model Hamiltonian includes Coulombic parameters B and C, interconfiguration interaction terms and the spin-orbit coupling for the 3d2 atomic configuration of Cr4+ and crystal-field terms in C4 symmetry. The parametrized Hamiltonian was diagonalized within the complete d2 configuration. Both free ion and crystal field parameters are presented.
Structural/Property Relationships for Optical Materials
Authors: Vivien D.  
Published: May 2017

AbstractIn this paper the relationships between the crystal structure, chemical composition and electronic structure of laser materials, and their optical properties are discussed. A brief description is given of the different laser activators and of the influence of the matrix on laser characteristics in terms of crystal field strength, symmetry, covalency and phonon frequencies. The last part of the paper lays emphasis on the means to optimize the matrix-activator properties such as control of the oxidation state and site occupancy of the activator and influence of its concentration.
The Effect of Growth Atmosphere Contamination on the Optical Quality of Fluoride Laser Crystals
Authors: Cassanho A. , Jenssen H. P. 
Published: May 2017

AbstractOxygen and moisture present in the growth atmosphere, may react with fluoride melts, compromising the optical quality of the grown crystals. Low level oxygen contamination can appear as an oxyfluoride coating over YLF boules without affecting their quality or as haze or milkiness in BaY2F8 and in LISAF and its analogs. Vacuum furnaces used to lower the level of these contaminants introduce hydrocarbon residues that might reduce the valence state of dopant ions such as Cr and Yb in some fluoride systems. Cr-doped LICAF and LISAF have similar behavior in contaminated atmospheres, whereas Cr-doped LISGAF displays very different behavior.
Spectra and Energy Levels of the Trivalent Ytterbium Ion Doped into Lithium Niobate by Thermal Indiffusion
Authors: Jones J. K. , Sandro J. P. De , Hempstead M. , Shepherd D. P. , Tropper A. C. , Wilkinson J. S. 
Published: May 2017

AbstractAn X-cut LiNbO3 substrate has been doped with Yb3+ ions by thermal diffusion from an Yb metal film of thickness 7nm. Polarised absorption and fluorescence spectra of the dopant ion have been measured using Ti-diffused y-propagating channel waveguides prepared in the doped region. Yb is a diode pumpable laser ion with characteristics that can be compared favourably with those of Nd in some respects; for example the small energy difference between pump and laser photons reduces thermal load facilitating high power operation. A waveguide laser geometry is particularly advantageous for Yb due to the quasi-3-level nature of the laser transition. The simple fabrication technique described here has been used to produce a system which may have the potential to operate as an Yb waveguide laser in an electro-optic host crystal.
New Saturable Absorber Q-Switch Materials for Solid State Lasers
Authors: Stultz Robert D. , Camargo Marly B. , Montgomery Suzanne T. , Birnbaum Milton , Spariosu Kalin 
Published: May 2017

AbstractWe have investigated new solid-state passive Q-switch materials for the Er:glass laser at 1.53 μm. Saturable absorber Q-switching has been obtained using Er3+:Ca5(PO4)3F, Er3 +:CaF2, and U4+:SrF2.
Improved Sol-Gel Materials for Efficient Solid State Dye Lasers
Authors: Canva Michael , Georges Patrick , Perelgritz Jean-Fran^ois , Brun Alain , Chaput Fréddric , Boilot Jean-Pierre 
Published: May 2017

AbstractPhotoresistant laser dyes were trapped in silica based xerogel host matrices to obtain solid state tunable lasers. For this purpose very dense xerogel samples with improved chemical and physical properties were prepared at room temperature by the sol-gel technology. The as-prepared materials were polished to obtain optical quality surfaces and were used as new lasing media.Lasing action of such different dyes as rhodamine, perylene and pyrromethene doping dense sol-gel matrices was demonstrated. Efficiencies of 30 % or lifetimes of more than 100,000 shots were achieved with different new ≤dye dopant/host matrix≥ couples. Their different performances are reviewed and discussed.
Comparison of Neodymium Laser Hosts Based on Fluoro-Apatite Structure
Authors: Loutts G. B. , Hong P. , Chai B. H. T. 
Published: May 2017

AbstractA comparative study of the Czochralski crystal growth of Ca and Sr fluoro-phosphate, Ca and Sr fluoro- and chloro-vanadate is reported. Sr fluoro-phosphate and fluoro-vanadate demonstrate the best overall properties and crystal quality. Codoping of the fluoro-apatite crystals with Si4+ or Ge4+ ions increases the neodymium distribution coefficient but somewhat deteriorate the Nd3+ emission.
Pressure Studies of Energy Transfer in Cr3+:Tm3+:YAG
Authors: Wamsley Paula R. , Bray Kevin L. 
Published: May 2017

AbstractThe effect of pressure on the spectrum and energy transfer properties of Cr3+:Tm3+:YAG has been considered. The results of cw and pulsed luminescence experiments are reported. The high pressure cw experiments demonstrate the existence of 1G4 → 3H5 emission from Tm3+. We believe this emission is also present in Tm3+:YAG at ambient pressure and has been previously misassigned. High pressure pulsed luminescence studies indicate a lengthening of the lifetime of Cr3+ in Cr3+:Tm3+.YAG and indicate that the rate of energy transfer from Cr3+ to Tm3+ decreases with increasing pressure. We interpret this result in terms of a destabilization of the 4T2 level of Cr3+ with increasing pressure.
Organic Single Crystals for Electronic and Optoelectronic Devices
Authors: Schön J. H. , Kloc Ch. , Dodabalapur A. , Batlogg B. 
Published: May 2017

ABSTRACTIn order to investigate the capabilities and limitations of organic semiconductor devices high-quality single crystals of these materials have been grown and their properties have been investigated. The observation of the Integer and Fractional Quantum Hall effect in organic semiconductors reveals the similarity to conventional inorganic semiconductor materials, such as Si or GaAs. In addition, electronic as well as optoelectronic devices based on such crystals have been prepared leading to the demonstration of ambipolar field-effect transistors and electrically- pumped solid state lasers.
Electric Field Induced Ionization of the Exciton in Poly(Phenylene Vinylene)
Authors: Wang Jian , Moses Daniel , Heeger Alan J. , Kirova N. , Brazovski S. 
Published: May 2017

ABSTRACTThe exciton binding energy (Eb) and the band gap energy (Eg) of poly(phenylene vinylene), PPV, have been determined by photoconductivity excitation profile spectroscopy as a function of light polarization, applied electric field, and temperature. The spectral signature of the exciton is a narrow peak (100 meV full width at half maximum) that emerges just below the band edge upon increasing the external field, the temperature or the defect density. The exciton peak is observed only for light polarized parallel to the chain axis. The exciton binding energy is obtained from the energy of the exciton peak with respect to the band edge and, independently from analysis of the field dependence of the exciton dissociation. It is Eb ≈ 60 meV.
Synthesis of New Building Blocks for Light Emitting Polymers
Authors: Fischmeister C. , Geneste F. , Holmes A. B. , Ma Y. , Martin R. E. , Sano T. , Tuan C.-S , Cacialli F. , Riehn R. H. , Friend R. H. 
Published: May 2017

ABSTRACTThe synthesis of poly(2,3-dibutoxy-1,4-phenylene vinylene) (DB-PPV) has allowed the study of this material as the active layer in a multiple layer device using a composite combination of polymer and Alq3 with an oxadiazole as electron injection/transport layers. The luminous efficiency of the resulting device was significantly improved as a result of this combination of transport layers. An entirely new approach to the synthesis of monomers for PPV precursors is described in which the 2- and 5- substituents are introduced by directed metallation groups (DMGs) which ultimately become the bis(halomethyl) groups.
Self-Assembly of Phenylene Ethynylene Diazonium Salts on Metal Surfaces as Potential Molecular Wires
Authors: Kosynkin Dmitry V. , Yang Jiping , Tour James M. 
Published: May 2017

ABSTRACTA series of substituted phenylene ethynylene diazonium salts were prepared from the corresponding anilines by the action of nitrosonium tetrafluoroborate in sulfolane-acetonitrile solvent. Formation of self-assembled layers of the diazonium salts in acetonitrile solution was demonstrated on Au, Cu and Pt surfaces. The self-assembly rate of the diazonium salts was found to be markedly dependent on the electron withdrawing character of the substituents attached to the aromatic rings.
Optical Modeling of Organic Light-Emitting Diode Multilayer Device Structures
Authors: Kahen K. B. 
Published: May 2017

ABSTRACTWe present an exact classical solution to the problem of dipole emission in a planar multilayer organic light-emitting diode (OLED) device. The inputs to the model are the photoluminescence and quantum yield of the emitter material, and the device layer thicknesses and indices of refraction. The results of the model are applied to predicting the radiant intensity of OLEDs as a function of varying device layer thickness. It is shown that the calculated radiances are in excellent agreement with the data; this suggests that at constant current the variation in electroluminescence caused by modifications of the layer thicknesses can be completely accounted for by optical effects. Finally, we present results (for positions both internal and external to the diodes) for the Poynting power distribution from a randomly aligned dipole in the emission layer.
Conjugated Polymer Thin Film Transistors Constructed Using Ohmic and Schottky Source/Drain Contacts
Authors: Lloyd Giles , Eccleston Bill 
Published: May 2017

ABSTRACTMeasurement and theory are presented for accumulation mode P3AT TFTs with Schottky and ohmic contacts. The polymer has been allowed to turn p type through exposure to air. Sample characteristics for gold contact TFTs are presented. Mobility values are 0.2 cm2/Vs and are comparable to the best reported.Using Schottky contacts as the source and drain electrodes can reduce off currents due to the existence of potential barriers at the contact. The presence, however, of the Schottky depletion region changes the mode of operation. A model is presented to describe the sub- threshold and gradual channel regions. Devices constructed using titanium show good agreement with the model. Transconductance for these devices is reduced when compared to ohmic contact devices with calculated mobilities of 0.01 cm2/Vs. Much smaller channel lengths are, however, possible in this technology. Off currents are found to be completely independent of gate voltage indicating good control of the off current by the Schottky junctions. Little or no gate modulation has been observed, to date, for aluminium and chromium contact devices.
Prediction of Charge Transport Properties of Molecular Materials by Ab Initio Molecular Orbital Calculations
Authors: Sotoyama Wataru , Hayano Tomoaki , Sato Hiroyuki , Matsuura Azuma , Narusawa Toshiaki 
Published: May 2017

ABSTRACTWe developed a method to predict the charge transport (CT) type (hole or electron) in molecular materials that uses molecular orbital calculations. The hole-and-electron-mobility ratios of molecular materials were calculated based on molecular structural reorganization energies in a charge hopping process. The CT types predicted from the calculated mobility ratios agreed with those experimentally obtained in seven of the eight model molecules.
Injecting Inter-Layers and the Built-in Potential of Blue Polymer Light-Emitting Diodes
Authors: Brown Thomas M. , Millard Ian S. , Lacey David J. , Burroughes Jeremy H. , Friend Richard H. , Cacialli Franco 
Published: May 2017

ABSTRACTThe semiconducting-polymer/injecting-electrode heterojunction plays a crucial part in the operation of organic solid state devices. In polymer light-emitting diodes (LEDs), a common fundamental structure employed is Indium-Tin-Oxide/Polymer/Al. However, in order to fabricate efficient devices, alterations to this basic structure have to be carried out. The insertion of thin layers, between the electrodes and the emitting polymer, has been shown to greatly enhance LED performance, although the physical mechanisms underlying this effect remain unclear. Here, we use electro-absorption measurements of the built-in potential to monitor shifts in the barrier height at the electrode/polymer interface. We demonstrate that the main advantage brought about by inter-layers, such as poly(ethylenedioxythiophene)/poly(styrene sulphonic acid) (PEDOT:PSS) at the anode and Ca, LiF and CsF at the cathode, is a marked reduction of the barrier to carrier injection. The electro- absorption results also correlate with the electroluminescent characteristics of the LEDs.
Large Area, Rubber Stamped Plastic Circuits for Electronic Paper
Authors: Rogers John A. , Baldwin Kirk , Bao Zhenan , Dodabalapur Ananth , Raju V.R. , Ewing Jay , Amundson Karl 
Published: May 2017

ABSTRACTThis paper illustrates the use of a high resolution form of rubber stamping, known as microcontact printing (μCP), for patterning plastic active matrix drive circuitry designed for electronic paper. The high resolution (∼1 [.mu]m) of the printed elements, the large area coverage (∼1 sq. ft.) and the good electrical performance of these systems suggest that the methods, materials and processing sequences may be attractive for realistic applications of plastic electronics.
Electrochromic Behavior of Ionically Self-Assembled Thin Films
Authors: Janik J.A. , Heflin J.R. , Marciu D. , Miller M.B. , Davis R.M. 
Published: May 2017

ABSTRACTIonically self-assembled monolayers (ISAMs), fabricated by alternate adsorption of cationic and anionic components, yield exceptionally homogeneous thin films with sub- nanometer control of the thickness and relative spatial location of the component materials. Using organic electrochromic materials such as polyaniline, we report studies of electrochromic responses in ISAM films. Reversible changes in the absorption spectrum are observed with the application of voltages on the order of 1.0 V. Measurements are made using both liquid electrolytes and in all-solid state devices incorporating solid polyelectrolytes such as poly(2- acylamido 2-methyl propane sulfonic acid) (PAMPS).
Theoretical and Experimental Studies of Third-Order Nonlinear Optical Susceptibilities of New p-N,N'-Diamethylaniline Tetrathiafulvalene Derivatives
Authors: Sahraoui B. , Pluciński K.J. , Makowaska-Janusik M. , Kityk I. V. , Salle M. , Gorgues A. 
Published: May 2017

ABSTRACTA study was made of third-order nonlinear optical susceptibilities of new tetrathiafulvalene (TTF) derivatives, using the degenerate four wave mixing (DFWM) method, as well as complex quantum chemical calculations. To understand the physical nature of the optical nonlinearities, we separated their electronic and nuclear contributions. We found that the electronic contribution to these nonlinearities predominated. Our investigations suggest that TTF may be a highly promising material for nonlinear optics (NLO).
Obrazy medialne – obrazy mentalne. Wybrane aspekty retoryki obrazu medialnego (na przykładzie wizerunku obcego/innego)
Authors: Cich Bernadeta , Drąg Katarzyna 
Published: May 2017

Artykuł dotyczy problemu dostosowania narzędzi do opisu retoryki obrazu medialnego i mentalnego. Wybrane aspekty zjawiska zostały pokazane na przykładach wizerunku obcego (Romowie, migranci) w mediach wizualnych. Retoryczny opis takiego komunikatu – tekstu medialnego – wymyka się narzędziom klasycznej retoryki, której przedmiotem opisu jest język. Powstaje potrzeba analizy tekstu obrazowego z uwzględnieniem warsztatu filmowego. Szkic dotyczy kultury wizualnej postrzeganej z perspektywy medioznawczej.
FDA Approval Summary: Pembrolizumab for the Treatment of Recurrent or Metastatic Head and Neck Squamous Cell Carcinoma with Disease Progression on or After Platinum-Containing Chemotherapy
Authors: Larkins Erin , Blumenthal Gideon M. , Yuan Weishi , He Kun , Sridhara Rajeshwari , Subramaniam Sriram , Zhao Hong , Liu Chao , Yu Jingyu , Goldberg Kirsten B. , McKee Amy E. , Keegan Patricia , Pazdur Richard 
Published: May 2017

Abstract
On August 5, 2016, the U.S. Food and Drug Administration granted accelerated approval to pembrolizumab (KEYTRUDA injection, Merck Sharp & Dohme Corp., Kenilworth, NJ) for treatment of patients with recurrent or metastatic head and neck squamous cell carcinoma (HNSCC) with disease progression on or after platinum-containing chemotherapy. Approval was based on the objective response rate (ORR) and duration of response (DoR) in a cohort of patients in a nonrandomized multi-cohort trial (KEYNOTE-012) that included 174 patients with recurrent or metastatic HNSCC who had disease progression on or after platinum-containing chemotherapy. Patients received either intravenous pembrolizumab 10 mg/kg every 2 weeks or 200 mg every 3 weeks. ORR was determined by independent review according to Response Evaluation Criteria in Solid Tumors 1.1. ORR was 16% (95% confidence interval 11, 22) with a complete response rate of 5%. DoR ranged from 2.4+ months to 27.7+ months. Twenty-three of 28 responding patients (82%) had response durations of ≥6 months. Safety was evaluated in 192 patients with HNSCC receiving at least one dose of pembrolizumab. Frequent (≥2%) serious adverse reactions were pneumonia, dyspnea, confusional state, vomiting, pleural effusion, and respiratory failure. Clinically significant immune-mediated adverse reactions included pneumonitis, colitis, hepatitis, adrenal insufficiency, diabetes mellitus, skin toxicity, myositis, and thyroid disorders. The benefit-risk profile of pembrolizumab was considered acceptable in this patient population. As a condition of accelerated approval, Merck is required to conduct a confirmatory trial; this trial, KEYNOTE-040, is ongoing.
Anticancer Activity from Active Fraction of Sea Cucumber
Authors: Putram Nurul Mutia , Setyaningsih Iriani , Tarman Kustiariyah 
Published: May 2017

Sea Cucumber Holothuria atra is one of marine organisms has been used as a new source of novel bioactive compounds. Many of them have been used as the lead compounds in discovery of new anticancer drugs. The objective of this study was to determine the active fractions of sea cucumber (H. atra) which have anticancer activity. H. atra was macerated using ethanol and the extract was freezedried using a freeze dryer. The crude extract was partitioned using n-hexane, ethyl acetate, and methanol-water (3:1:1:1). Cytotoxicity test was performed using HeLa (cervic cancer) cell line and MCF-7 (breast cancer) cell line based on the MTT assay. The crude extract of H. atra showed the best cytotoxic activity against HeLa cells (IC50 = 12.48 µg/mL) and MCF-7 cells (IC50 = 17.90 µg/mL). The toxicity tests showed the IC50 value of the n-hexane fraction, ethyl acetate fraction, and methanol-water fraction against HeLa cells HeLa (IC50 = 76.45 µg/mL; 77.95 µg/mL; 14.27 µg/mL) and MCF-7 cells (IC50 = 58.50 µg/mL; 59.59 µg/mL; 14.33 µg/mL).
Manual RBC exchange transfusion in a patient of sickle-beta thalassemia syndrome presenting in crisis: a case report
Authors: Kanungo Girija Nandini , Pati Bibudhendu , Das Hemlata , Routray Suman Sudha 
Published: May 2017

Sickle cell disease and beta thalassemia are caused by abnormal haemoglobin (Hb) derived from mutation of the HBB gene encoding beta-globin. Compound heterozygous status for both mutations results in HbS/beta thalassemia (Sickle- beta thalassemia). Vaso-occlusive phenomena and haemolysis are the clinical hallmarks and major causes of mortality. Here we report a case of successful reduction of HbS level by manual RBC exchange transfusion. Capillary zone electrophoresis showed the case to be Sickle-beta thalassemia. A total of 3 units of 450ml whole blood units were used for manual exchange transfusion done in 2 sittings on consecutive days. Preexchange HbS level was 80.9% of total Hb. HbS level after 24 hours of the second procedure was 44%. In the absence of facility to conduct automated RBC exchange by a cell separator, to reduce HbS in patients presenting with acute complications of SCD and in patients with Vaso-occlusive Crisis, previous stroke, manual RBC exchange can provide a better relief.