bluuebunny/crossref_metadata_2025 huggingface dataset:
Local Tunneling Barrier Height Studies of Thermally Treated CO- and O-covered Pt(100) Surfaces
Authors: Sinsarp Asawin , Miya Kenta , Yamada Yoichi , Sasaki Masahiro , Yamamoto Shigehiko
Published: February 2005

CO- and O-covered Pt(100) surfaces after thermal treatment have been studied by scanning tunneling microscopy (STM) and local tunneling barrier height (LBH) imaging. The coexistence of the reconstructed (hex) and reconstruction-deconstructed (1×1) domains with similar well-defined shapes is observed for both surfaces. However, the LBH images show that the local work function of the (1×1) domains is lower than that of the hex domains in the case of the CO-covered surface, but higher in the case of the O-covered surface. This feature is considered due to the electric dipole moment induced by O2adsorption being higher than that induced by CO adsorption.
Submolecular-Resolution Studies on Metal-Phthalocyanines by Noncontact Atomic Force Microscopy
Authors: Yoda Tadashi , Ichii Takashi , Fukuma Takeshi , Kobayashi Kei , Yamada Hirofumi , Matsushige Kazumi
Published: February 2005

Copper phthalocyanine (CuPc) thin films deposited on Au (111) surfaces were investigated by noncontact atomic force microscopy (NC-AFM). Structures with a periodic modulation of the spacing between the molecular rows of CuPc multilayer films were found. Submolecular features of each individual molecule on a film were successfully imaged. The obtained contrast was interpreted by the chemical interactions between a tip and the spatial electron density distribution of chemically active molecular orbitals such as highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO). In addition, the energy dissipation in the NC-AFM imaging of monolayer films was studied on a molecular scale. The obtained high-resolution contrast in the dissipation images was discussed in connection with the random fluctuation of molecules.
An Analysis of Size Effect on the Performances of Low-Leakage 0.10 µm Complementary Metal Oxide Semiconductor for 5-GHz Band Low-Power RF-ICs and Static Random Access Memory Applications
Authors: Lin Yo-Sheng
Published: February 2005

In this paper, we demonstrate the size effect on the DC and RF performances of 0.10 µm RF metal–oxide–semiconductor field effect transistors (MOSFETs) for 5-GHz band low-power radio-frequency integrated circuits (RF-ICs) and high-speed static random access memory (SRAM) applications. It was found that either one of the increase of device's width, the increase of gate-source voltage (when its corresponding transconductance (g
m) is smaller than the maximum g
m), and the decrease of measurement temperature can enhance the kink effect of both scattering parameters S
11 and S
22 because of the increase of g
m. A device with larger gate-width exhibits better RF noise and power performances because of higher gain and the lighter effect of parasitic extrinsic elements. In addition, the directly extracted equivalent Pucel's noise parameters P, R, and C of the MOSFETs can be used to calculate the noise figures of LNA's/mixers and the phase noise of oscillators, and thus is very helpful in the design of RF circuits.
A Study on Doping Density in InAs/GaAs Quantum Dot Infrared Photodetector
Authors: Lee Uk Hyun , Kang Yong Hoon , Oum Joon Ho , Lee Sang-Jun , Kim Moondok , Noh Sam Kyu , Jang Yu Dong , Lee Donghan , Kim Hyung Seok , Park Chan Hyung , Hong Songcheol
Published: February 2005

We study the influence of doping density and the resulting optimum operation voltage on the performance of quantum dot infrared photodetectors (QDIPs). The optimum operation voltage, where detectivity becomes maximum, becomes smaller as the doping density increases. This is because the optimum dark current levels are similar regardless of the doping density. We confirmed experimentally that the optimum dark current level is ∼5 mA (current density: ∼A/cm2) for our samples. It is found that the higher doping density improves the performance in the range used in this experiment (5×1016–5×1017/cm3). The response to a normal incident light is confirmed and the possibility of high-temperature operation of QDIP is shown.
Harmonic Injection-Locking Behavior of Frequency-Detuned Optical Pulse in Erbium-Doped Fiber Laser
Authors: Lin Gong-Ru , Liao Yu-Sheng , Wu Jung-Rung
Published: February 2005

The harmonic injection-locking dynamics of a gain-switched laser diode (GSLD) pulse-injection-locked Erbium-doped fiber amplifier-based laser (EDFL) are studied. Under GSLD injection with a pulsewidth and an average power of 17.6 ps and 0.2 mW, respectively, at a repetition frequency corresponding to the 223rd harmonic (996.8635971 MHz) of the EDFL, the pulsewidth, peak power, and phase noise of the injection-locked EDFL are broadening from 34.3 ps to 130 ps, decreasing from 1.8 W to 500 mW, and increasing from -101.5 dBc/Hz to -86 dBc/Hz, respectively, as the repetition frequency detunes toward the injection-locking margin. The injection-locking range is from -13 kHz to +27 kHz. The peak power of the broadened pulses is greatly reduced to one third of that at the zero-detuning condition even with a detuning frequency of ±5 kHz. The injection-locked EDFL pulse-train eventually disappears as the repetition frequency of the GSLD detuned beyond the injection-locking bandwidth. The timing jitter of the GSLD harmonic injection-locked EDFL remains unchanged (<0.5 ps) within a positive detuning frequency of <25 kHz, which is less stable at a negatively frequency-detuned regime.
Advances and Perspectives in Photonic Technology Research in the European Information Society Technologies Programme
Authors: Erasme Didier , Minot Christophe , Ohman Filip , Tromborg Bjarne , Ackaert Ann , Demeester Peter , Lagasse Paul , Politi Christina , O'Mahony Mike , Saniter Juergen , Patzak Erwin , Rao Sathya , Vogel Paul
Published: February 2005

The 5th framework programme, which the European Union launched in 1998, supported a wide range of industrial areas among which “Information Society Technologies (IST)” was one of the focus areas. The present paper presents a short overview of the research on photonic component technologies within the IST programme. It also presents the views on the future evolution of photonic component technologies for optical communications, which have emerged from a road map exercise within the thematic network OPTIMIST.
Measurement of Pump-Induced Absorption and Refractive Index Changes in GaInAsP/InP Waveguides Using an Optical Loop Mirror Interferometer
Authors: Seo J.-K. , Mizumoto T.
Published: February 2005

We investigated the direct measurement of intensity-dependent refractive index changes in GaInAsP/InP ridge waveguides with ps-order pump pulses below the band gap using an optical loop mirror interferometer. The temporal response of the probe in GaInAsP (λg=1410 nm) waveguides was shown to be instantaneous with respect to 4 ps pump pulses. The intensity-dependent refractive index coefficient was measured to be -2.0±0.6×10-12 cm2/W. In addition, pump-induced absorption changes were studied.
Analysis on the Compensating Thermal Lensing Effect Using a Convex Mirror in Vertical-Cavity Surface-Emitting Lasers
Authors: Uchida Takeshi , Miyamoto Tomoyuki , Koyama Fumio
Published: February 2005

We proposed the compensation of a thermal lensing effect and transverse-mode control by applying a curved mirror in vertical-cavity surface-emitting lasers. Results indicate that a convex mirror with a proper curvature compensates for a thermal lensing.
Magnetic Alignment at Reduced Field Intensity Due to Decrease of Temperature Observed for Nonferromagnetic Particles Possessing Paramagnetic and Diamagnetic Anisotropy
Authors: Uyeda Chiaki , Tanaka Kenta , Takashima Ryouichi , Sakakibara Makoto
Published: February 2005

The reduction of field intensity to achieve magnetic alignment of micron-sized nonferromagnetic particles caused by the variations of various parameters was studied systematically, based on the experimental data obtained for various non ferromagnetic materials. The field intensity where the order parameter reached =0.8, denoted by B
s, was proportional to the square root of temeprature for graphite crystals free of paramagnetic ions. The relationship was consistent with the Langevin theory on magnetic alignment. The majority of inorganic oxides is expected to possess diamagnetic anisotropy, since their origin can be explained quantitatively by assuming a constant anisotropy on the individual bonding orbital composing the material. B
s is expected to decrease with the temperature for these oxides, in the same manner observed for the graphite grains. Experiments on talc and kaolinite particles including paramagnetic ions revealed that B
s was proportional to temperature when the paramagnetic concentration was high, since the paramagnetic anisotropy followed the Curie law.
Multi-Curve Fitting Analysis of Temperature-Dependent I-V Curves of Poly-Hexathienylphenanthroline-Bridged Nanogap Electrodes
Authors: Araki Koiti , Endo Hiroaki , Tanaka Hirofumi , Ogawa Takuji
Published: February 2005

Stable junctions were obtained by preparing polymeric hexathienylphenanthroline wires coordinated to [RuII(bpy)2](PF6)2 groups directly in Au electrode nanogaps by electropolymerization. Reproducible nonlinear and strongly temperature-dependent curves, similar to those found for self-assembled π-conjugated dithiols and diisocyanides inside nanoholes, were obtained rather than a tunneling behavior commonly found in alkanethiol self-assembled monolayers. This is the first time that a consistent series of data are collected for a polymer and interpreted based on a multicurve fitting method, based on the linear combination of tunneling, Frankel-Pool and hopping mechanims, indicating that various independent conduction pathways are present in the junctions.
Epitaxial Growth of Rutile TiO2 Films on MgO Substrate in Inductively Coupled Plasma-Assisted Sputtering
Authors: Okimura Kunio , Furumi Takahiro
Published: February 2005

Rutile TiO2 films were epitaxially grown on MgO(100) substrates by inductively coupled plasma-assisted sputtering. At the substrate temperature of 300°C, the prepared films showed epitaxial growth with relation of rutile TiO2(110)[001] ∥ MgO(100)[011]. Post-annealing in atmospheric O2 at 600°C and 800°C improved the crystalline preference resulting in a full width at half maximum (FWHM) of rocking curve of 2.4° at 800°C. The films prepared by conventional sputtering also showed rutile TiO2 textured growth; however, annealing behavior revealed defective structures of deposited films.
Highly c-oriented LiNbO3Films on Polycrystalline Diamond Substrate for High Frequency Surface Acoustic Wave Devices
Authors: Lam Hi Ki , Dai Ji Yan , Chan Helen Lai-Wai
Published: February 2005

Highlyc-oriented LiNbO3films were deposited on aluminum oxide (Al2O3) buffered diamond substrates by a novel two-step pulsed laser deposition. The two-step growth method (growth at 500 mTorr oxygen partial pressure for 15 s followed by 12 min growth at 100 mTorr oxygen pressure) greatly enhanced thec-oriented LiNbO3film crystallinity and improved the film surface flatness. The Al2O3buffer layer was shown to be able to protect the diamond surface from oxidation during LiNbO3film growth under high oxygen pressure and also favorable forc-oriented LiNbO3film growth. By utilizing such a stacked structure of LiNbO3/Al2O3/diamond, surface acoustic wave devices were fabricated and characterized.
Temperature-Dependent Electron Transport Properties of AlGaN/GaN Heterostructures
Authors: Lee Chien-Chi , Shih Cheng-Feng , Lee Chien-Ping , Tu Ru-Chin , Chuo Chang-Cheng , Chi Jim
Published: February 2005

In this article, a comparison on the temperature dependence of the electron transport properties of the undoped and modulation-doped AlGaN/GaN heterostructures is presented. The results obtained indicate that the device structure plays an important role in the temperature-dependent transport behavior of the devices. The undoped structure has a nearly constant 2DEG concentration over a wide temperature range. The modulation-doped structure has a temperature-dependent electron concentration. The increase in electron concentration in the modulation-doped structure at high temperatures is due to the thermal activation of Si donors in the AlGaN layer. In addition, the modulation-doped structure shows comparable electron mobility with the undoped structure at high temperatures, indicating that the modulation-doped structure would exhibit a better device performance at high temperatures.
Stiffness of Step Bunches on Si(111)
Authors: Omi Hiroo , Homma Yoshikazu
Published: February 2005

Configurations of atomic steps on vicinal Si(111) miscut toward the [112] direction after homoepitaxial step-flow growth were studied as a function of growth thickness by ex situ atomic force microsocopy. We found that step bunches coarsen via the zipping-up of single, double, triple, and quadruple bilayer steps during the growth, and that the zipping steps contact neighboring step bunches at characteristic angles depending on their heights. The new finding of the step-height-dependence enabled us to evaluate step bunch stiffness. The step bunches are shown to be significantly stabilized compared with a simple summation of stiffness of individual single bilayer steps.
Molecular Beam Epitaxy of Highly [100]-Oriented β-FeSi2 Films on Lattice-Matched Strained-Si(001) Surface Using Si0.7Ge0.3 Layers
Authors: Saito Tatsuma , Suemasu Takashi , Yamaguchi Kenji , Mizushima Kazuki , Hasegawa Fumio
Published: February 2005

We have grown highly [100]-oriented β-FeSi2 continuous films on lattice-matched Si(001) surfaces using Si0.7Ge0.3 layers by molecular beam epitaxy (MBE). The β-FeSi2 films grown on the lattice-matched Si(001) did not aggregate even when it was grown at temperatures above 600°C. The omega-scan full width at half maximum of the β-FeSi2(800) peak was smaller than that of the film grown on Si(001) over the entire growth temperature ranging from 500 to 720°C. X-ray diffraction pole figure measurements revealed that a [100]-oriented β-FeSi2 template layer is necessary to obtain [100]-oriented β-FeSi2 films by MBE even on the lattice-matched Si(001).
Cl− secretory effects of EBIO in the rabbit conjunctival epithelium
Authors: Alvarez Lawrence J. , Zamudio Aldo C. , Candia Oscar A.
Published: February 2005

Experiments were conducted to determine whether the Cl− secretagogue, 1-ethyl-2-benzimidazolinone (EBIO), stimulates Cl− transport in the rabbit conjunctival epithelium. For this study, epithelia were isolated in an Ussing-type chamber under short-circuit conditions. The effects of EBIO on the short-circuit current ( Isc) and transepithelial resistance ( Rt) were measured under physiological conditions, as well as in experiments with altered electrolyte concentrations. Addition of 0.5 mM EBIO to the apical bath stimulated the control Isc by 64% and reduced Rt by 21% ( P < 0.05; paired data). Under Cl−-free conditions, Isc stimulation using EBIO was markedly attenuated. In the presence of an apical-to-basolateral K+ gradient and permeabilization of the apical membrane, the majority of the Isc reflected the transcellular movement of K+ via basolateral K+ channels. Under these conditions, EBIO in combination with A23187 elicited nearly instantaneous 60–90% increases in Isc that were sensitive to the calmodulin antagonist calmidazolium and the K+ channel blocker tetraethyl ammonium. In the presence of an apical-to-basolateral Cl− gradient and nystatin permeabilization of the basolateral aspect, EBIO increased the Cl−-dependent Isc, an effect prevented by the channel blocker glibenclamide (0.3 mM). The latter compound also was used to determine the proportion of EBIO-evoked unidirectional 36Cl− fluxes in the presence of the Cl− gradient that traversed the epithelium transcellularly. Overall, EBIO activated apical Cl− channels and basolateral K+ channels (presumably those that are Ca2+ dependent), thereby suggesting that this compound, or related derivatives, may be suitable as topical agents to stimulate fluid transport across the tissue in individuals with lacrimal gland deficiencies.
Color of Scents: Chromatic Stimuli Modulate Odor Responses in the Human Brain
Authors: Österbauer Robert A. , Matthews Paul M. , Jenkinson Mark , Beckmann Christian F. , Hansen Peter C. , Calvert Gemma A.
Published: February 2005

Color has a profound effect on the perception of odors. For example, strawberry-flavored drinks smell more pleasant when colored red than green and descriptions of the “nose” of a wine are dramatically influenced by its color. Using functional magnetic resonance imaging, we demonstrate a neurophysiological correlate of these cross-modal visual influences on olfactory perception. Subjects were scanned while exposed either to odors or colors in isolation or to color-odor combinations that were rated on the basis of how well they were perceived to match. Activity in caudal regions of the orbitofrontal cortex and in the insular cortex increased progressively with the perceived congruency of the odor-color pairs. These findings demonstrate the neuronal correlates of olfactory response modulation by color cues in brain areas previously identified as encoding the hedonic value of smells.
Crossmodal Integration in the Primate Superior Colliculus Underlying the Preparation and Initiation of Saccadic Eye Movements
Authors: Bell Andrew H. , Meredith M. Alex , Van Opstal A. John , Munoz Douglas P.
Published: February 2005

Saccades to combined audiovisual stimuli often have reduced saccadic reaction times (SRTs) compared with those to unimodal stimuli. Neurons in the intermediate/deep layers of the superior colliculus (dSC) are capable of integrating converging sensory inputs to influence the time to saccade initiation. To identify how neural processing in the dSC contributes to reducing SRTs to audiovisual stimuli, we recorded activity from dSC neurons while monkeys generated saccades to visual or audiovisual stimuli. To evoke crossmodal interactions of varying strength, we used auditory and visual stimuli of different intensities, presented either in spatial alignment or to opposite hemifields. Spatially aligned audiovisual stimuli evoked the shortest SRTs. In the case of low-intensity stimuli, the response to the auditory component of the aligned audiovisual target increased the activity preceding the response to the visual component, accelerating the onset of the visual response and facilitating the generation of shorter-latency saccades. In the case of high-intensity stimuli, the auditory and visual responses occurred much closer together in time and so there was little opportunity for the auditory stimulus to influence previsual activity. Instead, the reduction in SRT for high-intensity, aligned audiovisual stimuli was correlated with increased premotor activity (activity after visual burst but preceding saccade-aligned burst). These data provide a link between changes in neural activity related to stimulus modality with changes in behavior. They further demonstrate how crossmodal interactions are not limited to the initial sensory activity but can also influence premotor activity in the SC.
Adhesion molecules and cardiovascular risk in peripheral arterial disease
Authors: Schiano Vittorio , Scopacasa Francesco , Chiariello Massimo , Silvestro Antonio , Brevetti Gregorio
Published: February 2005

Although intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) play a relevant role in atherosclerosis, little is known about the prognostic impact of their soluble forms (s) in patients with peripheral arterial disease (PAD). The aim of this prospective study was to verify whether plasma levels of s ICAM-1 and s VCAM-1 predict cardiovascular risk in PAD, and improve the prognostic value of the ankle/brachial index (ABI) alone. Accordingly, plasma levels of sICAM-1 and sVCAM-1, and the ABI were measured in 75 PAD patients who were monitored for a mean of 24±13 months. Twenty-two (29.3%) patients had a cardiovascular event (15 coronary, 3 cerebrovascular and 4 peripheral events). Plasma levels of sVCAM-1 were 618±258 ng/mL in patients with and 496±164 ng/mL in those without an event (p= 0.016). The corresponding sICAM-1 values were 344±239 ng/mL and 275±99 ng/mL (p= 0.079). The cardiovascular event rate was higher in patients with sVCAM-1 levels above the median than in those with sVCAM-1 below the median (p=0.0027 by log rank test). Independent predictors of events were sVCAM-1 levels above the median (p=0.005) and an ABI below the median (p= 0.001). Amongst patients with ABI below the median, the occurrence of sVCAM-1 above the median was associated with a 3.4-fold increase in risk (95% CI 1.308 to 9.573, p= 0.013). In conclusion, increased plasma levels of sVCAM-1 have a negative prognostic impact in PAD and improve the predictive value of ABI, which is currently the most powerful risk indicator in these patients.
Nitroaspirin plus clopidogrel versus aspirin plus clopidogrel against platelet thromboembolism and intimal thickening in mice
Authors: Momi Stefania , Pitchford Simon , Alberti Paolo , Minuz Pietro , Del Soldato Piero , Gresele Paolo
Published: February 2005

Clopidogrel plus aspirin is the treatment of choice for patients undergoing percutaneous, coronary interventions with stenting, but it does not prevent restenosis. NCX-4016, a nitric oxide-releasing aspirin (nitroaspirin), exerts a wider range of antiplatelet actions compared to aspirin, superior antithrombotic activity and reduces restenosis after arterial injury in animals. The aim of the present study was to compare the combination of nitroaspirin plus clopidogrel with aspirin plus clopidogrel in a model of platelet pulmonary thromboembolism, bleeding and intimal thickening in mice. Drugs were administered orally for 5 days; the antithrombotic effects were evaluated against collagen plus epinephrine-induced pulmonary thromboembolism, the haemorrhagic effects by tail transection bleeding time and the effects on neointima proliferation by histomorphology of photochemically injured femoral arteries. Lung platelet emboli were reduced significantly and more effectively by nitroaspirin plus clopidogrel (-56%, p< 0.05 vs control) than by aspirin plus clopidogrel (-26%, p< 0.05 vs control). Ex vivo platelet aggregation was inhibited maximally by nitroaspirin plus clopidogrel. Aspirin plus clopidogrel strikingly prolonged the bleeding time while nitroaspirin plus clopidogrel induced a lesser prolongation. Nitroaspirin plus clopidogrel significantly reduced intimal thickening of the femoral artery while aspirin plus clopidogrel was ineffective. Nitroaspirin plus clopidogrel is more effective and less prohaemorrhagic than aspirin plus clopidogrel in mice; provided these data are confirmed in other animal models, nitroaspirin plus clopidogrel may represent a new regimen to be tested in patients undergoing coronary revascularization procedures.
Effects of aspirin, clopidogrel and dipyridamole administered singly and in combination on platelet and leucocyte function in normal volunteers and patients with prior ischaemic stroke
Authors: Zhao Lian , Fletcher Sally , Weaver Chris , Leonardi-Bee Jo , May Jane , Fox Sue , Willmot Mark , Heptinstall Stan , Bath Philip
Published: February 2005

The aim of this study was to assess whether triple antiplatelet therapy is superior to dual and mono therapy in attenuating platelet and leucocyte function. Aspirin (A), clopidogrel (C), and dipyridamole (D) were administered singly and in various combinations (A, C, D, AC, AD, CD, ACD), each for two weeks (without washout) to 11 healthy subjects and to 11 patients with previous ischaemic stroke in two randomised multiway crossover trials. At the end of each two-week period platelet aggregation, platelet-leucocyte conjugate formation and leucocyte activation were measured ex vivo blinded to treatment. Platelets were stimulated with collagen; additional measurements were made with adenosine diphosphate (ADP), platelet activating factor (PAF), adrenaline and the combination of, ADP, PAF and adrenaline. Results show that in the presence of collagen, ACD was superior to all antagonists or combinations, except AC, in reducing aggregation, platelet-leucocyte conjugate formation, and monocyte activation (all p< 0.05). ACD was also more potent than other treatments, except AC, in inhibiting the aggregation and platelet-monocyte conjugate formation induced by the combination of ADP, PAF and adrenaline. The effects were similar in both volunteers and stroke patients. No serious adverse events or major bleeding events occurred. Triple antiplatelet therapy did not appear to be more effective than combined aspirin and clopidogrel in moderating platelet and leucocyte function. Any additional clinical benefit provided by dipyridamole may be through other mechanisms of action.
Role of fibrinolytic and clotting parameters in the diagnosis of liver veno-occlusive disease after hematopoietic stem cell transplantation in a pediatric population
Authors: Spiezia Luca , Cesaro Simone , Messina Chiara , Paris Myriam , Pillon Marta , Saggiorato Graziella , Pagnan Antonio , Girolami Antonio , Zanesco Luigi , Cella Giuseppe , Teresa Sartori Maria
Published: February 2005

Hepatic veno-occlusive disease (VOD) is a severe complication after hematopoietic stem cell transplantation (HSCT). Recent studies, mainly in adults receiving HSCT, have identified an increase in the plasminogen activator inhibitor-1 (PAI-1) as a possible marker of VOD. To confirm this finding, the fibrinolytic, coagulation and liver function parameters were assayed before and weekly for 1 month after 61 HSCT performed in 53 consecutive children. Non-VOD patients had a slight increase in t-PA antigen, fibrinogen and P-selectin levels, as well as a mildly longer aPTT and a drop in antithrombin after HSCT. The 6 children with VOD (9.84%) had an early and significant increase in PAI-1 antigen and activity (p< 0.0001), t-PA antigen (p< 0.0001) and D-dimer (p< 0.01) levels, and a decrease in plasminogen, α2-antiplasmin and PT emerged 2(±1) days before the clinical diagnosis of VOD by comparison with mean post-HSCT values in the non-VOD patients. Significant differences were also detected for these parameters and antithrombin levels between non-VOD and VOD patients soon after the clinical onset of VOD, whereas the rise in bilirubin levels became significant only later on. In conclusion, variations in fibrinolytic test findings after HSCT, and PAI-1 in particular, may facilitate the early diagnosis of VOD in pediatric patients after HSCT.
Contribution of haplotypes across the fibrinogen gene cluster to variation in risk of myocardial infarction
Authors: Eriksson Per , Lundman Pia , Samnegård Ann , Boquist Susanna , Ericsson Carl-Göran , Tornvall Per , Hamsten Anders , Silveira Angela , Mannila Maria
Published: February 2005

Fibrinogen has consistently been recognized as an independent predictor of myocardial infarction (MI). Multiple mechanisms link fibrinogen to MI; therefore disentangling the factors underlying variation in plasma fibrinogen concentration is essential. Candidate regions in the fibrinogen gamma (FGG), alpha (FGA) and beta (FGB) genes were screened for single nucleotide polymorphisms (SNPs). Several novel SNPs were detected in the FGG and FGA genes in addition to the previously known SNPs in the fibrinogen genes. Tight linkage disequilibrium extending over various physical distances was observed between most SNPs. Consequently, eight SNPs were chosen and determined in 377 postinfarction patients and 387 healthy individuals. None of the SNPs were associated with plasma fibrinogen concentration or MI. Haplotype analyses revealed a consistent pattern of hap-lotypes associated with variation in risk of MI. Of the four haplo-types inferred using the FGA –58G> A and FGG 1299+79T> C SNPs, the most frequent haplotype, FGG-FGA*1 (prevalence 46.6%), was associated with increased risk of MI (OR 1.51; 95%CI 1.18, 1.93), whereas the least frequent haplotype, FGGFGA*4 (11.8%), was associated with lower risk of MI (OR 0.79 95%CI 0.64, 0.98). In conclusion, fibrinogen haplotypes, but not SNPs in isolation, are associated with variation in risk of MI.
Basal high-sensitivity-C-reactive protein levels in patients with spontaneous venous thromboembolism
Authors: Vormittag Rainer , Vukovich Thomas , Schönauer Verena , Lehr Stephan , Minar Erich , Bialonczyk Christine , Hirschl Mirko , Pabinger Ingrid
Published: February 2005

The role of C-reactive protein (CRP) in venous thromboembolism (VTE) is still under discussion because of controversial results in the literature. Conflicting data may have partly been due to bias by exogenous factors altering CRP levels. We investigated CRP concentrations in patients with spontaneous VTE applying a study design that allowed the measurement of basal high sensitivity (hs)-CRP levels. Patients with a history of deep vein thrombosis (DVT, n=117) and pulmonary embolism (PE, n=97) were compared to healthy individuals (n=104). Hs-CRP levels (mg/dl) were significantly higher in patients (n=214, median/interquartile range: 0.171/0.082–0.366) than in controls (0.099/0.053–0.245, p=0.001). The unadjusted odds ratio (OR) for VTE per 1 mg/dl increase of CRP was 2.8 [95% confidence interval (CI): 1.1–6.8, p=0.03]. This association remained significant after adjustment for factor V Leiden, prothrombin G20210A and factor VIII activity above 230% (OR = 2.9, 95% CI [1.1–7.5]), but became remarkably attenuated and lost its statistical significance after adjustment for BMI alone (OR = 1.7 [0.7–4.0]). CRP was also not independently associated with VTE in subgroups of patients (those with DVT without symptomatic PE, those with PE and patients without established risk factor) in multiple regression analysis. In summary, we observed significantly higher basal hs-CRP levels in patients with spontaneous VTE compared to healthy controls. This association was independent of hereditary and laboratory risk factors for VTE, but lost its significance after adjustment for BMI. Increased basal CRP levels do not appear to represent an independent risk factor for VTE.
Corporate Governance and Business Ethics in North America: The State of the Art
Authors: Ryan Lori Verstegen
Published: February 2005

All three corporate governance systems in North America are currently embroiled in fundamental transformations. Most of Mexico’s corporations are run by a small group of controlling shareholders and operate in an economic system rife with corruption. Recent political reforms and a desire to tap global equity markets have heightened their interest in improving corporate governance structures. United States corporations face a dispersed ownership base that has tended toward inattentiveness, allowing such infamous scandals as Enron to rock the global investing community. A backlash against the ensuing, restrictive Sarbanes-Oxley legislation is now underway. Like Mexico’s, Canada’s major corporations are led by a handful of controlling shareholders, but corruption is uncommon. New corporate governance guidelines are under debate, and the Ontario Securities Commission is wresting control from the Toronto Stock Exchange. Although these three corporate governance systems vary in terms of ownership dispersion, level of corruption, and legislative intervention, they currently share a common focus on fundamental reform.
Corporate Governance, Values Management, and Standards: A European Perspective
Authors: Wieland Josef
Published: February 2005

This article brings forward the argument that the practical implementation of a corporate governance code cannot be realized by a compliance program alone. Its relevance in everyday business is determined by the moral values of the company culture. In this context, governance is defined as a company’s resources and capabilities, including the moral resources, to take on responsibility for all its stakeholders. A critical discussion of the agency theory, transaction cost theory, and organization theory shows that such an approach is possible only when a company is not perceived as a maximizing machine for shareholders’ interests but as an economic form of cooperation of internal and external resources and stakeholders. An empiric study on 22 European corporate governance codes shows that the predominant majority of European codes orientate themselves to stakeholders and the company. The discussion of the empirical data reveals six basic principles that determine all European corporate governance codes: shareholder rights, transparency, voting rights, regulation of remuneration, design of organizational structures, and corporate social responsibility.
Faculty First
Authors: Costa Jennifer , McPhail Gary , Smith Janet , Brisk María Estela
Published: February 2005

The increasing number of English language learners (ELLs) in U.S. schools requires rethinking teacher education (TE). Most teachers have received little preparation in how to educate ELLs. Change in TE programs is needed to ensure that TE students are prepared to teach ELLs. Such change begins by educating TE faculty first. One catalyst for change, a faculty institute in which faculty, doctoral students, and public school personnel participated, is described here. Analysis of the process, the content, and course changes illustrated this TE program’s efforts to infuse the curriculum with ELL scholarship. Change occurred with respect to individual faculty knowledge and awareness and resulted in changes to course syllabi. Emerging issues during the process illustrate how context influenced this change effort. TE programs need to adopt changes in order to graduate teachers confident in their knowledge of and preparation for multilingual and multicultural populations in order to serve all pupils effectively.
Cytokine-mediated regulation of activating and inhibitory Fcγ receptors in human monocytes
Authors: Liu Yi , Masuda Emi , Blank Marissa C , Kirou Kyriakos A , Gao Xiaoni , Park Mee-Soon , Pricop Luminita
Published: February 2005

Fcγ receptors (FcγR) trigger inflammatory reactions in response to immunoglbulin-opsonized pathogens and antigen-antibody complexes. The coordinate expression of activating and inhibitory FcγR ensures the homeostasis of immune complex-driven inflammatory responses. In this study, we used antibodies with preferential binding for activating FcγRIIa and inhibitory FcγRIIb receptors to investigate the expression and regulation of FcγRII isoforms in human monocytes. Cross-linking of FcγRIIa triggered phagocytosis and cytokine production. Cross-linking of FcγRIIb was associated with phosphorylation of the immunoreceptor tyrosine-based inhibitory motif and with a marked reduction in monocyte effector functions. Our study revealed that tumor necrosis factor α (TNF-α), interleukin (IL)-10, and IL-13 altered the transcriptional activity of the FcγRIIB promoter in transfected cell lines and skewed the balance of activating versus inhibitory FcγR in human monocytes. TNF-α decreased the expression of inhibitory FcγRIIb. IL-10 up-regulated all classes of FcγR and induced alternative activation in monocytes, an effect that was synergistic with that of TNF-α. In contrast, IL-4 and IL-13, in combination with TNF-α, decreased the expression of activating FcγR and markedly down-regulated FcγR-mediated function. Our findings suggest that the cytokine milieu can induce changes in the relative expression of FcγR with opposing function and thus, may regulate the amplitude of FcγR-mediated uptake and inflammation.
The ectodysplasin pathway in feather tract development
Authors: Houghton Leslie , Lindon Catherine , Morgan Bruce A.
Published: February 2005

The ectodysplasin pathway, comprising the ligand ectodysplasin, its receptor Edar and a dedicated death domain adaptor protein Edaradd, plays an important role in epidermal organ formation in mammals. Mutations in the genes encoding these proteins cause dysplasia or absence of teeth, sweat glands and hair follicles. However, the relative position of this pathway in the regulatory hierarchy directing follicle formation remains unclear. In this work, the chicken orthologs of Eda, Edar and Edaradd were cloned to exploit the temporal precision of the feather tract system in order to study the role of the ectodysplasin pathway. We find that these genes are expressed in a similar pattern during feather and hair development, with the notable difference that the ligand Eda, which is expressed in the epidermis of the mouse, is expressed in the dermis of the feather tract. Contrary to conclusions reached from the analysis of mutant mice, we find that localization of Edar expression to the nascent placode is coincident or subsequent to the local expression of other markers of placodal differentiation, and not an upstream event in tract patterning. Furthermore, forced expression of BMP and activated β-catenin demonstrate that local expression of Edar is dictated by the interaction between these two pathways. These results suggest that activation of the ectodysplasin pathway may be permissive for activating signals to overcome signals that inhibit placode formation, but the function of this pathway in the specification of follicle initiation lies downstream of other patterning events.
TGFβ/activin/nodal signaling is necessary for the maintenance of pluripotency in human embryonic stem cells
Authors: James Daylon , Levine Ariel J. , Besser Daniel , Hemmati-Brivanlou Ali
Published: February 2005

Human embryonic stem cells (hESCs) self-renew indefinitely and give rise to derivatives of all three primary germ layers, yet little is known about the signaling cascades that govern their pluripotent character. Because it plays a prominent role in the early cell fate decisions of embryonic development, we have examined the role of TGFβ superfamily signaling in hESCs. We found that, in undifferentiated cells, the TGFβ/activin/nodal branch is activated (through the signal transducer SMAD2/3) while the BMP/GDF branch(SMAD1/5) is only active in isolated mitotic cells. Upon early differentiation, SMAD2/3 signaling is decreased while SMAD1/5 signaling is activated. We next tested the functional role of TGFβ/activin/nodal signaling in hESCs and found that it is required for the maintenance of markers of the undifferentiated state. We extend these findings to show that SMAD2/3 activation is required downstream of WNT signaling, which we have previously shown to be sufficient to maintain the undifferentiated state of hESCs. Strikingly, we show that in ex vivo mouse blastocyst cultures, SMAD2/3 signaling is also required to maintain the inner cell mass (from which stem cells are derived). These data reveal a crucial role for TGFβ signaling in the earliest stages of cell fate determination and demonstrate an interconnection between TGFβ and WNT signaling in these contexts.
Intergenerational Persistence of Earnings: The Role of Early and College Education
Authors: Restuccia Diego , Urrutia Carlos
Published: February 2005

Recent empirical evidence from the United States indicates a high degree of persistence in earnings across generations. Designing effective public policies to increase social mobility requires identifying and measuring the major sources of persistence and inequality in earnings. We provide a quantitative model of intergenerational human capital transmission that focuses on three sources: innate ability, early education, and college education. We find that approximately one-half of the intergenerational correlation in earnings is accounted for by parental investment in education, in particular early education. We show that these results have important implications for education policy.
Does Fund Size Erode Mutual Fund Performance? The Role of Liquidity and Organization
Authors: Chen Joseph , Hong Harrison , Huang Ming , Kubik Jeffrey D
Published: February 2005

We investigate the effect of scale on performance in the active money management industry. We first document that fund returns, both before and after fees and expenses, decline with lagged fund size, even after accounting for various performance benchmarks. We then explore a number of potential explanations for this relationship. This association is most pronounced among funds that have to invest in small and illiquid stocks, suggesting that these adverse scale effects are related to liquidity. Controlling for its size, a fund's return does not deteriorate with the size of the family that it belongs to, indicating that scale need not be bad for performance depending on how the fund is organized. Finally, using data on whether funds are solo-managed or team-managed and the composition of fund investments, we explore the idea that scale erodes fund performance because of the interaction of liquidity and organizational diseconomies.
An Efficient Ascending-Bid Auction for Multiple Objects
Authors: Ausubel Lawrence M
Published: February 2005

When bidders exhibit multi-unit demands, standard auction methods generally yield inefficient outcomes. This article proposes a new ascending-bid auction for homogeneous goods, such as Treasury bills or telecommunications spectrum. The auctioneer announces a price and bidders respond with quantities. Items are awarded at the current price whenever they are “clinched,” and the price is incremented until the market clears. With private values, this (dynamic) auction yields the same outcome as the (sealed-bid) Vickrey auction, but has advantages of simplicity and privacy preservation. With interdependent values, this auction may retain efficiency, whereas the Vickrey auction suffers from a generalized Winner's Curse.
Method to Rapidly Assess the Index Properties of Fine-Grained Dredged Materials
Authors: Lee LT
Published: February 2005

Rapid assessment and characterization of very soft fine-grained soils may be desired in a field or laboratory situation when an estimate of soil properties is needed in advance of time-consuming standard laboratory procedures. For example, the need for rapid assessment may include geotechnical parameter estimation for preliminary design or jobsite quality control monitoring for specification compliance. One such method enabling parameter estimation or prediction consists of an adaptive technique called the “slump test” developed from a nongeotechnical materials test method. It is shown to be a viable tool for estimating index properties and remolded soil behavior. Correlations explored in this paper include water content, void ratio, Atterberg limits, and engineering behavior properties.
Evaluation of Liquefaction Potential and Dynamic Properties of Silty Sand Using Cyclic Triaxial Testing
Authors: Sitharam TG , GovindaRaju L , Srinivasa Murthy BR
Published: February 2005

The recent earthquake that struck the Bhuj area of Gujarat State in India on 26 January 2001 has caused almost a total devastation of several hundred buildings in villages and cities. Liquefaction triggered by this earthquake caused major damage to structures resting on Loose to medium dense sands. This earthquake provides grave illustrations of the importance of understanding the seismic response of such deposits. Recent developments in numerical analyses for nonlinear dynamic responses of ground due to strong earthquake motions have increased the demand for dynamic soil properties corresponding not only at small strain level but also at large strain level. In this paper, the results of cyclic undrained tests are presented for liquefied soil close to the epicenter of the Bhuj earthquake. From these tests the dynamic properties were estimated at large strain levels of 0.5 % to 4 %. The modulus and damping estimated using cyclic triaxial testing at large strain levels might serve as a key factor for assessment of ground response due to earthquakes.
Measurement and Simulation of Damage to Long Light-Weight Packages in the FedEx 3-Day Saver Parcel Delivery Service
Authors: Singh SP , Burgess G , Mingerink C
Published: February 2005

Packaged goods are shipped daily using the single parcel distribution systems offered by carriers such as FedEx, UPS, and USPS. Through these shipments, packages are exposed to dynamic forces that result in punctures, creases, scuffs, tape failures, and corner and edge crushes. This study measured the frequency and severity of these and other types of damage that occur to long light-weight packages in the FedEx single parcel environment (3-Day Saver). The results of this study showed that the most frequent type of damage in one-way shipments were creases, which represented 61.5 % of the damage events observed. Corner crushes followed with 16.7 %, edge crushes with 6.8 %, punctures with 6.7 %, and tape failures with 1.7 % of the total damages observed. Based on 58 packages shipped, the average box experienced 8.4 creases, 2.3 corner crushes, 0.9 punctures, 0.9 edge crushes, 0.8 others, 0.2 tape failures, and 0.1 scuffs per shipment. Based on these results, a test protocol was developed to reproduce this damage. The test includes vibration testing, compression testing with an edge hazard, at drop onto a point hazard, tip-over test onto an edge hazard, and corner and edge drop tests. The proposed tests correlated well with actual damage.
The Use of an Alternative Method for Fracture Toughness Evaluation on Different Materials
Authors: Guardiola M , Bernal C , Martínez R , Cassanelli A
Published: February 2005

Through this paper an alternative procedure to obtain fracture toughness parameters on blunt-notched samples rather than on standard sharp-notched samples has been applied to several materials which display different fracture behavior. An aluminum alloy, an austempered ductile iron (ADI), and two different polymeric materials, polyamide 6 and poly(methyl methacrylate) (PMMA), were tested. The use of the alternative methodology allows simplification and cost reduction in fracture toughness evaluation. For the aluminum alloy, the fracture parameter obtained by this method was 16 % lower than that determined using ASTM standard methodology with data scatter similar to that reported in literature. For the ADI, fracture toughness values from blunt-notched samples were close to those obtained using standard test samples, showing low sensitivity to the changes in the crack tip diameter. For polyamide 6, the alternative methodology led to a toughness value within the same range of the values obtained from the traditional technique. In the case of the PMMA, the KIc values obtained from both methods showed good agreement.