bluuebunny/crossref_metadata_2025_split huggingface dataset:
The value of hyperbilirubinaemia in the diagnosis of acute appendicitis
Authors: Emmanuel Andrew , Murchan Peter , Wilson Ian , Balfe Paul 
Published: April 2011

INTRODUCTION No reliably specific marker for acute appendicitis has been identified. Although recent studies have shown hyperbilirubinaemia to be a useful predictor of appendiceal perforation, they did not focus on the value of bilirubin as a marker for acute appendicitis. The aim of this study was to determine the value of hyperbilirubinaemia as a marker for acute appendicitis. MATERIALS AND METHODS A retrospective analysis of appendicectomies performed in two hospitals (n=472). Data collected included laboratory and histological results. Patients were grouped according to histology findings and comparisons were made between the groups. RESULTS The mean bilirubin levels were higher for patients with simple appendicitis compared to those with a non-inflamed appendix (p<0.001). More patients with simple appendicitis had hyperbilirubinaemia on admission (30% vs 12%) and the odds of these patients having appendicitis were over three times higher (odds ratio: 3.25, p<0.001). Hyperbilirubinaemia had a specificity of 88% and a positive predictive value of 91% for acute appendicitis. Patients with appendicitis who had a perforated or gangrenous appendix had higher mean bilirubin levels (p=0.01) and were more likely to have hyperbilirubinaemia (p<0.001). The specificity of hyperbilirubinaemia for perforation or gangrene was 70%. The specificities of white cell count and C-reactive protein were less than hyperbilirubinaemia for simple appendicitis (60% and 72%) and perforated or gangrenous appendicitis (19% and 36%). CONCLUSIONS Hyperbilirubinaemia is a valuable marker for acute appendicitis. Patients with hyperbilirubinaemia are also more likely to have appendiceal perforation or gangrene. Bilirubin should be included in the assessment of patients with suspected appendicitis.
Displacement Current Measurement of MIS Devices with Ionic
Liquids to Explore Carrier Behaviors in Model Interfaces of Organic
Devices
Authors: Yamada Taiki , Noguchi Yutaka , Ouchi Yukio , Ishii Hisao 
Published: April 2011

ABSTRACTCharge injection property of organic thin film devices is a key issue to
understand the device operation. Displacement current measurement (DCM) is a
powerful technique to probe the charge injection behaviors in terms of a
change in the apparent capacitance of test devices. However, it requires to
suppress actual current flowing through the device for investigating the
details of interface phenomena. We propose here the use of ionic liquids
(ILs) as a top contact insulator in organic metal-insulator-semiconductor
(MIS) structures. Because of the high stability and dielectric constant of
the ILs, the external applied voltage was applied mainly to the organic
layer with suppressing the actual current. The DCM curves of Pt
wire/IL/α-NPD/ITO structure were measured, and they actually show the
signals due to the hole injection from theITO to α-NPD layer and
accumulation at the IL/α-NPD.
Electrical Conductance of Single Oligothiophene Molecular Wires:
Temperature Effect
Authors: Lee See Kei , Yamada Ryo , Tanaka Shoji , Tada Hirokazu 
Published: April 2011

ABSTRACTWe investigated temperature dependence of the electrical conductance of
single oligothiophene molecular wires with the length of 2.2 nm (5-mer), 5.6
nm (14-mer) and 6.7 nm (17-mer) by using the scanning tunneling microscopy
break junction method. Results show that the dominant charge carrier
transport for 5-mer molecule is tunneling while for 17-mer molecule is
hopping. The carrier transport mechanism of 14-mer are tunneling transport
(T ≤ 350 K) and hopping transport (T > 350 K) indicating that hopping and
tunnelling transport are competitive process in the molecular junction.
The direct measurement of energy barrier height at metal/
polyfluorene derivatives interface by internal photoemission
spectroscopy
Authors: Itoh Eiji , Takaishi Shinya 
Published: April 2011

ABSTRACTWe have investigated the barrier height for electron injection at the
cathode / polyflu-orene derivatives interface by the internal photoemission
(IPE) spectroscopy techniques using the “electron only device” structure
consisting of TiO2, electron transporting polyimide inter-layer
(IL), and polyfluorene derivatives. We also estimated the barrier height by
the current analysis based on the Schottky thermal emission current model,
and it coincides well to the threshold energy of IPE result only when the
energy is lower than 1.1eV. The measured barrier height obtained by IPE
linearly increases with both the work-function of cathode materials.
However, the slope parameter becomes less than 1 (~0.6) for poly
(9,9-dioctylfluorene) (F8) probably due to the interfacial gap states. On
the other hand, the slope parameter becomes very small (~0.18) for the poly
(9,9-dioctylfluorene)-co- benzo- thiadiazole) (F8BT) probably due to the
electron pinning at the cathode/ acceptor interface.
Twin-domain Epitaxial Growth and Metal-insulator Transition of VO2 Thin Film on C-Plane Sapphire
Authors: Chen Changhong , Zhao Yong , Pan Xuan , Holtz Mark , Fan Zhaoyang 
Published: April 2011

ABSTRACTWe report heteroepitaxial growth of VO2 thin film on c-plane sapphire by pulsed DC magnetron sputtering. X-ray diffraction experiment indicates that the 150 nm thick film is in triple-domain (020)-epitaxial structure with six-fold rotational symmetry in the basal plane; in particular, off-axis Φ scans from (011) and (220) show twin and triple peaks in each group of the diffraction profiles due to angle β mismatch and V4+-V4+ dimerization, respectively. The epitaxial relationship between VO2 and c-plane sapphire can be concluded as be ${\rm{VO}}_{\rm{2}} \left[ {{\rm{010}}} \right]{\rm{ }}\left\&#x007C; {{\rm{Al}}_{\rm{2}} {\rm{O}}_{\rm{3}} \left[ {{\rm{0001}}} \right]\,{\rm{and}}\,{\rm{VO}}_{\rm{2}} {\rm{ }}\left({{\rm{\bar 202}}} \right){\rm{ }}} \right\&#x007C;{\rm{Al}}_{\rm{2}} {\rm{O}}_{\rm{3}} \left\{ {11\bar 20} \right\}$, with the in-plane lattice mismatch of 2.66% (tensile) along $\left[ {\bar 202} \right]$ and the out-of-plane lattice mismatch of -2.19% (compressive). Temperature dependence of resistivity in van der Pauw method shows that the resistivity changes by ~5 orders of magnitude through the metal-insulator transition, and a narrow hysteresis window of ~3 K is obtained between cooling and heating cycles with respect to phase-transition temperatures at 347.1 and 350.1 K.
Structural and Ferroelectric Properties of Large c/a Phase Bismuth Ferrite Thin Films Prepared by Ion Beam Sputtering
Authors: Nakashima Seiji , Tsujita Yosuke , Fujisawa Hironori , Park Jung Min , Kanashima Takeshi , Okuyama Masanori , Shimizu Masaru 
Published: April 2011

ABSTRACTBiFeO3 (BFO) thin films have been deposited on SrRuO3/SrTiO3 (001) substrate by using ion beam sputtering process. At low oxygen partial pressure of 11 m Pa, rhombohedral and large c/a mixed phase thin film have been obtained in spite of rhombohedral BFO single phase formation at high oxygen partial pressure of 73 mPa. From wide area 2θ-Ψ mappings, diffraction peaks from large c/a phase BFO thin film were obtained with the same extinction rule as those of rhombohedral BFO. Reciprocal space mappings around BFO (003) and BFO (103) spots indicate that lattice parameters of large c/a phase BFO were a = 0.381 nm and c = 0.461 nm (c/a =1.22), respectively. Moreover ferroelectric domain switching could be observed in both of rhombohedral BFO and mixed phase BFO thin films.
Oxidative Jet Deposition of Polythiophenes
Authors: Gilpin A. Davison , Boerio F. James 
Published: April 2011

ABSTRACTAn oxidative jet deposition process was used to deposit films of polythiophenes. The oxidative jet is created using two different methods, an ozone jet or a plasma jet. An ozone jet is created by forcing a gas mixture containing oxygen through a corona-discharge apparatus. A plasma jet is created by forcing an ionization gas through a radio-frequency plasma chamber. Polymerization and film deposition was achieved by rastering the jet over a substrate while a monomer was injected into the oxidative jet. The injected monomers include thiophene, 2-methylthiophene, 3-methylthiophene, and 3,4-ethylenedioxythiophene (EDOT). The resulting films were studied with Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and time-of-flight secondary ion mass spectrometry (TOF-SIMS). FTIR spectra of the jet deposited films were characteristic of undoped poly(3,4-ethylenedioxythiophene) PEDOT. FTIR spectra showed that parameter optimized plasma jet deposited films contained less overoxidation in the form of hydroxyl and carbonyl groups than films deposited through the ozone jet process. The fabrication of organic electronics could be improved by this technology because a jet process allows for inline processing. Inline processing offers practical industrial advantages over the batch process methods currently used for depositing films of polythiophenes.
Quasi-pyramidal texturing using phase-segregated masks
Authors: Saenger Katherine L. , Carruthers Roy , Fogel Keith E. , Inns Daniel 
Published: April 2011

ABSTRACTSurface texturing processes for thin silicon solar cells ideally remove as little Si as possible relative to amount of topography generated. Here we describe how a micron-scale quasi-pyramidal texture may be achieved in Si layers with arbitrary crystallinity using a phase-segregated mask in combination with reactive ion etching (RIE). The Si to be textured is coated with a thin barrier layer followed by a layer of Al-Si alloy which phase-segregates into micron-sized regions of Al and Si after low temperature (<450 °C) annealing. One omponent of the mask is selectively etched away and the Si under the exposed barrier regions is etched by a process that gives the desired depth and lateral undercut. In this paper we show the dependence of the segregated Al-Si morphology on Al-Si alloy composition, thickness, and annealing conditions, and then present examples of texturing produced in single crystal Si by these masks in combination with CF4/O2 reactive ion etching.
High-rate Etching of Organic Materials using Gas Cluster Beam
Authors: Suda Takanori , Toyoda Noriaki , Yamada Isao 
Published: April 2011

ABSTRACTOrganic materials or polymers, which are widely used in electronic devices, are easily damaged by energetic ion or electron bombardment. Therefore, it is difficult to use conventional ion or electron beam processes for etching organic materials. In this study, a gas cluster beam possessing kinetic energy of the order of several hundred eV was used as a novel means to realize high-rate, low-damage etching. Polyethylene (PE) and polyvinyl chloride (PVC) were used as the target organic materials. Using a SF6 cluster beam, the etching depth suddenly increased when the nozzle gas pressure exceeded 0.6 MPa, as in the case of cluster beam formation. When the SF6 gas pressure in the nozzle was 1.2 MPa, the etching rates of PVC and PE were 2.88 μm/s and 1.62 μm/s, respectively. The dependence of the etching effect on cluster size was studied by varying the gas temperature. The etching depth of PVC increased with increasing average cluster size and intensity of the beam. The flow rate of the gas was constant; hence, etching of the organic materials did not occur because of the individual impact of the molecular beam. In fact, it occurred because of the neutral cluster, which had a large total kinetic energy. The energy per molecule of the gas cluster beam is of the order of several tens of meV; hence, high-rate, low-damage etching of organic materials can be potentially achieved.
Formation of Silicon and Silicon-Based Semiconductor Materials via Photoinduced Reaction Using Femtosecond Laser
Authors: Nishimura Masakazu , Kanehira Shingo , Sakakura Masaaki , Shimotsuma Yasuhiko , Miura Kiyotaka , Hirao Kazuyuki 
Published: April 2011

ABSTRACTWe have succeeded in silicon (Si) precipitation inside a glass/aluminum (Al) sandwich structure via photoinduced reaction using femtosecond (fs) laser irradiation. The sandwich structure was fabricated by direct bonding below 573 K. Raman spectra at the photomodified area indicated that Si crystals formed at the interface between the glass and metallic Al after the laser irradiation. In addition, the particle size of the precipitated Si could be changed by changing the pulse energy of the laser. Furthermore, we have also focused the laser pulses on Fe-Si film to trigger crystallization and phase transformation of FexSiy at the interface between Fe/Si multilayer and glass.
Coupling of Defect Fields to Domains and Phase Transition Characteristics of Ferroelectric Thin Films with Charged Defects
Authors: Misirlioglu Ibrahim B. , Cologlu Hale N. , Yildiz Mehmet 
Published: April 2011

ABSTRACTWe analyze the effect of charged defects on the electrical domains, phase transition characteristics and electrical properties of ferroelectric thin films with thin dead layers using a non-linear thermodynamic model. Depending on their density and field strength, defects can pin and couple to electrical domains in the film. For ultrathin films, depolarizing effects dominate and the transition from the paraelectric state is into the multidomain ferroelectric state during cooling and is strongly smeared. The competition between defect induced extrinsic effects and the dead layer related limit is demonstrated.
TEM studies of the ternary Ti36 Al62 Nb2 alloy
Authors: Chakravadhanula V.S.K. , Kelm K. , Kienle L. , Duppel V. , Lotnyk A. , Sturm D. , Heilmaier M. , Schmitz G. J. , Drevermann A. , Stein F. , Palm M. 
Published: April 2011

ABSTRACTAl-rich Ti-Al alloys attracted some attention during the past years due to the possibility of their application as light-weight, high-performance materials at elevated temperatures. The effect of the addition of Nb to Al-rich Ti-Al alloys has been studied for Ti36 Al62 Nb2 by a combined approach of transmission electron microscopy (TEM) techniques for unraveling the structure and composition at the nanoscale. Structural analyses on as-cast ternary alloys revealed the presence of h-TiAl2-, Ti3Al5- and γ-TiAl-type phases. After heat treatment, phase transformations like the replacement of the metastable h-TiAl2-type by the stable r-TiAl2-type were identified. Additionally, changes of the microstructural features like the formation of interfaces with different orientation relationships are apparent. The orientation and interfacial relationships involved are compared to those of binary Ti-Al alloys rich in Al.
Robustness versus Performance Assessment for Different Gamma-TiAl Processing Routes
Authors: Thomas Marc 
Published: April 2011

ABSTRACTOne of the main driving force for the development of advanced structural materials is weight saving especially in the transportation industry in order to reduce CO2 emission. The utilization of gamma aluminides, as good candidates for aerospace applications, is strongly related to the development of a cost-effective and robust processing route, as far as possible. It is well established that the processing route, i.e. cast, wrought or PM, has a dramatic effect on the microstructure and texture of gamma-TiAl alloys. Therefore, significant microstructural variations through post-heat treatments coupled with compositional modifications can only guarantee a proper balance of desired properties. However, a number of metallurgical factors during the processing steps can contribute to some scattering in properties. This review will highlight several critical process variables in terms of the resulting g-TiAl microstructures. Of primary importance is the as-cast texture which is difficult to control and may contribute to prefer some alternative processing routes to ensure a better repeatability in mechanical results. Some innovative processing techniques for controlling the structure will then be presented. The main point which will be discussed in this paper is whether an approach leading to a robust process would not be at the expense of the high performance of the structural material.
Effects of Geometric Constraint on Phase Selection and Segregation in Cast TiAl
Authors: Zhang Sailei , Johnson David R. , Krane Matthew J.M. 
Published: April 2011

ABSTRACTSimulations of directional solidification of binary peritectic TiAl alloys through ceramic preforms consisting of narrow straight channels with spacings on the order of the dendritic tip radius were performed with a modified cellular automaton coupled to a finite volume calculation of solute diffusion. Depending upon the channel spacing, the microstructure may be refined after dendritic growth through the preform. As the channel width decreases, the lateral solute diffusion in the liquid is more constrained, changing the morphology of the primary phase from dendritic to cellular. In narrow channels, the liquid concentration gradient ahead of the solid/liquid interface decreases resulted in lower growth velocities and higher undercoolings. For hypo-peritectic TiAl alloys, growth conditions that lead to growth of β dendrites can result in α nucleation and growth in narrow channels due to the geometric constraint on solute diffusion.
Mechanical Properties of Cr5Si3 with the D8m Structure
Authors: Ochiai Yuji , Kishida Kyosuke , Tanaka Katsushi , Inui Haruyuki 
Published: April 2011

ABSTRACTElastic properties, thermal expansion and deformation behavior of Cr5Si3 with the D8m structure were investigated using single crystals. From the values of Cauchy pressures as well as the ratio of the polycrystalline bulk modulus (B) to shear moduls (G) estimated from single-crystal elastic constants (cij), deformation behavior of Cr5Si3 is expected to be relatively brittle compared to Mo5Si3 with the same crystal structure. However, plastic deformation of Cr5Si3 is confirmed above 900 ~ 1100 °C depending on the loading axis orientations.
Synthesis and Microstructure of Porous Aluminum and Intermetallic Nanomaterials
Authors: Purdy Andrew P. , Miller Joel B. 
Published: April 2011

ABSTRACTA series of porous aluminum-based materials are prepared by the reduction of solutions of metal chlorides with lithium powder in diethyl ether under dry argon. The reactants must be combined slowly, but either order of addition is used. The reduction of AlCl3 produces hollow Al balls composed of ~100 nm aluminum particles in nearly quantitative yield after the LiCl byproduct is washed away with dry tetrahydrofuran. Similar structures are formed when mixtures of AlCl3 and SiCl4, are reduced, except that the second component has the effect of reducing the Al nanoparticle size. Mixtures of AlCl3 with FeCl3 reduce to similar ball-like porous structures that are composed of Al, Fe, and Fe-Al intermetallic nanoparticles. When AlCl3 and ZnCl2 are co-reduced, flake-like nanoporous structures are obtained, and solutions of AlCl3 + VCl3 produce more compact nanoporous structures. Some side reactions involving ether cleavage that produces aluminum alkoxides and alkyls do occur, and the amount of side reaction is dependent on the identity of the second metal. The reduction of AlCl3 with excess (4 eq) Li powder produces LiAl nanomaterials. NMR shows the intermetallic compound LiAl to be the only Li-Al intermetallic present.
Microstructural and mechanical properties of ternary Mo-Si-B alloys resulting from different processing routes
Authors: Krüger Manja , Heilmaier Martin , Shyrska Veronika , Loboda Petr I. 
Published: April 2011

ABSTRACTMo-base silicide alloys take advantage of their outstanding intrinsic properties, notably the high melting point and, thus, their excellent mechanical and creep strength. We demonstrate how the processing route influences the microstructure and consequently the mechanical and oxidation behaviour. Therefore two fabrication routes, a powder metallurgical (PM) and a zone melting (ZM) process, both starting from elemental powders, were used to prepare several Mo-Si-B alloys with varying chemical compositions. While PM processing leads to an ultrafine microstructure with a continuous Mo solid solution (“α-Mo”) matrix and embedded particles of the two intermetallic compounds Mo3Si and Mo5SiB2, the directionally solidified (ZM) materials possess a coarse grained structure composed of an intermetallic matrix with dendritic islands of α-Mo. A comparative assessment of the mechanical behaviour of the alloys utilizing both the Vickers indentation fracture (VIF) technique and three-point bending tests emphasizes the beneficial effect of a continuous Mo matrix resulting in increased room temperature fracture toughness and a reduction of the brittle-to-ductile-transition-temperature (BDTT). Likewise, the positive effect of the fine grained and homogeneous microstructure on oxidation performance is shown by the evaluation of mass change during heat treatment at 1100°C.
Study of the effect of Al, Cr and Sn additions on the microstructure and properties of Nb silicide based alloys
Authors: Tsakiropoulos P , Zelenitsas K , Vellios N 
Published: April 2011

ABSTRACTThe effects of Al, Cr and Sn on segregation, microstructure, phase stability and hardness of Nb-24Ti-18Si-5X (X = Al, Cr, Sn, at%) alloys were studied. The microstructure of the as cast alloys with Cr, Al and Sn respectively contained (Nb,Ti)ss, Nb3Si, αNb5Si3 and C14-NbCr2 Laves, (Nb,Ti)ss and βNb5Si3 and (Nb,Ti)ss, Nb3Sn and Nb5Si3. The microstructures of the heat treated alloys with Al and Cr (1500 oC/100 h) contained (Nb,Ti)ss and αNb5Si3 and the alloy with Sn (1200 oC/100 h) contained (Nb,Ti)ss, Nb3Sn and αNb5Si3. Compared with Al and Cr, alloying with Sn enhanced the stability of the as cast microstructure, caused strong macrosegregation of Si and Ti, suppressed the segregation of Ti in the (Nb,Ti)ss that was promoted by Al and Cr, had the strongest effect on the macrohardness of the cast and heat treated alloys and on the vol% of the Nbss. All three alloying additions promoted the transformation of βNb5Si3 to αNb5Si3 during heat treatment and decreased the hardness of Nb5Si3 in the as cast alloys with Sn having the strongest effect and Al the weakest. After the heat treatment the hardness of Nb5Si3 increased in the alloys containing Cr and Sn and decreased in the Al containing alloy with Cr having the strongest effect.
Morphology change of γ′ precipitates in γ/γ′ two-phase microstructure in Co-based superalloys by higher-order alloying
Authors: Tanaka Katsushi , Ooshima Masahiro , Okamoto Norihiko L. , Kishida Kyosuke , Inui Haruyuki 
Published: April 2011

ABSTRACTChanges in the morphology of γ′ precipitates in a γ/γ′ two-phase microstructure in Co-based superalloys, which occur through higher-order alloying, have been investigated. The shape of γ′ precipitates changes from a cuboid to an irregularly rounded shape when the Ta content increases to 4 at.%. The irregular shape of the γ′ precipitates changes to cuboid again upon further alloying with 2 at.% Mo. Changes in the morphology of γ′ precipitates are closely related to variations in the lattice misfit between γ and γ′ phases upon alloying. A lattice misfit increases with an increase in Ta content, which makes γ/γ′ interfaces incoherent when the lattice misfit exceeds a critical value. On the contrary, the lattice misfit decreases upon alloying with Mo. Changes in the lattice misfit upon alloying are well explained through the partition behavior of alloying elements and their atomic volume.