bluuebunny/crossref_metadata_2025 huggingface dataset:
Identification of protein expression signatures in gastric carcinomas using clustering analysis
Authors: Begnami Maria D , Fregnani José Humberto T G , Brentani Helena , Torres Cesar , Costa Jr Wilson Luiz , Montagnini Andre , Nonogaki Suely , Soares Fernando A
Published: July 2011

Background and Aim:  The identification of gastric carcinomas (GC) has traditionally been based on histomorphology. Recently, DNA microarrays have successfully been used to identify tumors through clustering of the expression profiles. Random forest clustering is widely used for tissue microarrays and other immunohistochemical data, because it handles highly‐skewed tumor marker expressions well, and weighs the contribution of each marker according to its relatedness with other tumor markers. In the present study, we e identified biologically‐ and clinically‐meaningful groups of GC by hierarchical clustering analysis of immunohistochemical protein expression.

Methods:  We selected 28 proteins (p16, p27, p21, cyclin D1, cyclin A, cyclin B1, pRb, p53, c‐met, c‐erbB‐2, vascular endothelial growth factor, transforming growth factor [TGF]‐βI, TGF‐βII, MutS homolog‐2, bcl‐2, bax, bak, bcl‐x, adenomatous polyposis coli, clathrin, E‐cadherin, β‐catenin, mucin (MUC)1, MUC2, MUC5AC, MUC6, matrix metalloproteinase [MMP]‐2, and MMP‐9) to be investigated by immunohistochemistry in 482 GC. The analyses of the data were done using a random forest‐clustering method.

Results:  Proteins related to cell cycle, growth factor, cell motility, cell adhesion, apoptosis, and matrix remodeling were highly expressed in GC. We identified protein expressions associated with poor survival in diffuse‐type GC.

Conclusions:  Based on the expression analysis of 28 proteins, we identified two groups of GC that could not be explained by any clinicopathological variables, and a subgroup of long‐surviving diffuse‐type GC patients with a distinct molecular profile. These results provide not only a new molecular basis for understanding the biological properties of GC, but also better prediction of survival than the classic pathological grouping.
Time saving with narrow‐band imaging for distinguishing between neoplastic and non‐neoplastic small colorectal lesions
Authors: Sakamoto Taku , Matsuda Takahisa , Aoki Takaya , Nakajima Takeshi , Saito Yutaka
Published: July 2011

Background and Aims:  For colonoscopic examinations, the narrow‐band imaging (NBI) system is more convenient and timesaving than magnifying chromoendoscopy (MCE). However, the time‐saving aspects of NBI techniques have not been assessed. The present study compared interpretation times between NBI and MCE techniques in distinguishing between neoplastic and non‐neoplastic small colorectal lesions.

Methods:  Between January and March 2010, 693 consecutive patients who underwent colonoscopy at the National Cancer Center Hospital, Tokyo, Japan, were enrolled. When the first lesion was detected by conventional white‐light observation, the patient was randomly assigned to undergo a sequence of NBI and MCE observations (group A: NBI–MCE, group B: MCE–NBI). The time to diagnosis with each modality (NBI, from changing to NBI until diagnosis; MCE, from the start of indigo carmine solution spraying until diagnosis) was recorded by an independent observer. The sensitivity, specificity, and diagnostic accuracy of the first modality used in each group (NBI or MCE) were assessed by referring to the histopathological data.

Results:  Seventy‐one patients with 137 lesions were randomized to group A, and 80 patients with 163 lesions to group B. The median interpretation times were 12 s (interquartile range [IQR]: 7–19 s) in group A, and 17 s (IQR: 12–24 s) in group B, the difference being significant (P < 0.001). No significant differences were observed between NBI and MCE in terms of sensitivity, specificity, and diagnostic accuracy.

Conclusions:  NBI reduces the interpretation times for distinguishing between neoplastic and non‐neoplastic small lesions during colonoscopies, without loss of diagnostic accuracy.
Immunohistochemical biomarkers for bladder cancer prognosis
Authors: Matsushita Kazuhito , Cha Eugene K , Matsumoto Kazumasa , Baba Shiro , Chromecki Thomas F , Fajkovic Harun , Sun Maxine , Karakiewicz Pierre I , Scherr Douglas S , Shariat Shahrokh F
Published: July 2011

Urothelial carcinoma of the bladder (UCB) is an especially complex and heterogeneous disease with a broad spectrum of histologic findings and potentially lethal behavior. Despite advances in surgical techniques, as well as intravesical and systemic therapies, up to 30% of patients with non‐muscle‐invasive UCB and 50% of patients with muscle‐invasive UCB experience disease progression, recurrence, and eventual death. Standard prognostic features, such as pathologic stage and grade, have limited ability to predict the outcomes of this heterogeneous population. Current risk‐stratification algorithms using clinical and pathologic parameters are limited in their prognostic ability. Molecular medicine holds the promise that clinical outcomes will be improved by more accurate prognostication and directing therapy towards the mechanisms and targets associated with the growth of an individual patient's tumor. Immunohistochemical analysis of biomarker expression has provided insight into the molecular pathogenesis of UCB and offers the potential for improving clinical decision making. Numerous candidate immunohistochemical biomarkers for patients with UCB have been identified, with those relating to the cell cycle and apoptosis/cell proliferation being the most extensively studied. The present review discusses the most promising immunohistochemical biomarkers. Special attention is paid to recent data from a multi‐institutional collaboration that has implemented a regulated, phased biomarker discovery and validation pathway. Because UCB tumorigenesis and progression is a process involving multiple genetic and epigenetic alterations, multiple biomarkers need to be integrated into a prognostic signature to accurately predict outcomes. There is no doubt that biomarkers will eventually guide our clinical decision making regarding follow‐up scheduling and treatment choice.
Health‐related quality of life after salvage high‐intensity focused ultrasound (HIFU) treatment for locally radiorecurrent prostate cancer
Authors: Berge Viktor , Baco Eduard , Dahl Alv A , Karlsen Steinar Johan
Published: July 2011

Objective:  To evaluate health‐related quality of life (HRQOL) after salvage high‐intensity focused ultrasound (HIFU) for locally radiorecurrent prostate cancer (PCa).

Methods:  Since June 2006 we have treated 61 patients consecutively by salvage HIFU. All patients were offered the University of California, Los Angeles Prostate Cancer Index (UCLA‐PCI) questionnaire at baseline and at follow‐up. Scores ranged from 0 (worst) to 100 (best). Clinically significant changes were defined as a minimum difference of 10 points between the baseline score and the score at follow‐up.

Results:  Fifty‐seven patients (93%) had evaluable data at baseline, compared with 46 (75%) after treatment. The mean time lapse between HIFU treatment and questionnaire response was 17.5 months (range 6–29 months). The mean score for urinary function decreased from 79.7 ± 12.1 prior to HIFU to 67.4 ± 17.8 after HIFU (P < 0.001). The mean score for sexual function decreased from 32.1 ± 24.1 prior to HIFU to 17.2 ± 17.0 after HIFU (P < 0.001). There were no significant effects on bowel function. There was a significant reduction in the mean score for Physical HRQOL, but the mean score for Mental HRQOL was did not change significantly.

Conclusion:  Treatment of localized radiorecurrent PCa by salvage HIFU is associated with clinically significant reductions in urinary and sexual function domains after a mean follow‐up of 17.5 months.
HOW TRADITIONAL ARE THE AMERICAN, FRENCH AND GERMAN TRADITIONS OF PUBLIC ADMINISTRATION? A RESEARCH AGENDA
Authors: SAGER FRITZ , ROSSER CHRISTIAN , HURNI PASCAL Y. , MAVROT CÉLINE
Published: July 2011

Consistent with the notion of tradition, public administration scholars usually interpret and compare administrative developments in the US, France, and Germany as inheritance, assuming continuity. However, administrative traditions have thus far not been an object of systematic research. The present research agenda aims to address this research gap by introducing the transfer‐of‐ideas approach as a means to examine the empirical substance of national traditions. We claim that for current research, the benefits of this approach are twofold. First, the transfer‐of‐ideas approach contributes to comparative public administration since it reveals in how far intellectual traditions are hybrid instead of distinctively American, French or German developments. Second, the approach may help to address the polysemous meanings of and terminological difficulties within administrative concepts that prevail in Public Administration on both sides of the Atlantic.
Strategic Privatization in Developing Countries
Authors: Bjorvatn Kjetil , Eckel Carsten
Published: July 2011

Privatization of state‐owned enterprises may have important welfare implications, in particular in less developed economies where markets are small and domestic firms are typically relatively weak, both technologically and financially. In these environments, a high‐tech foreign investor acquiring the state‐owned assets may end up dominating the local market, thereby harming local consumer and producer interests. A foreign investor, however, is likely to be both willing and able to offer a higher bid for the assets than local investors. This paper addresses the trade‐off for local governments between privatization revenues and foreign market power. The authors find that there may be an incentive to privatize “strategically” by selling the state‐owned firm to a local (less advanced) investor at a lower price in order to achieve a more competitive post‐privatization market structure.
Effects of the Analgesic Acetaminophen (Paracetamol) and its para‐Aminophenol Metabolite on Viability of Mouse‐Cultured Cortical Neurons
Authors: Schultz Stephen , DeSilva Mauris , Gu Ting Ting , Qiang Mei , Whang Kyumin
Published: July 2011

Abstract: Acetaminophen has been used as an analgesic for more than a hundred years, but its mechanism of action has remained elusive. Recently, it has been shown that acetaminophen produces analgesia by the activation of the brain endocannabinoid receptor CB1 through its para‐aminophenol (p‐aminophenol) metabolite. The objective of this study was to determine whether p‐aminophenol could be toxic forin vitrodeveloping mouse cortical neurons as a first step in establishing a link between acetaminophen use and neuronal apoptosis. We exposed developing mouse cortical neurons to various concentrations of drugs for 24 hrin vitro. Acetaminophen itself was not toxic to developing mouse cortical neurons at therapeutic concentrations of 10–250 μg/ml. However, concentrations of p‐aminophenol from 1 to 100 μg/ml produced significant (p < 0.05) loss of mouse cortical neuron viability at 24 hr compared to the controls. The naturally occurring endocannabinoid anandamide also caused similar 24‐hr loss of cell viability in developing mouse cortical neurons at concentrations from 1 to 100 μg/ml, which indicates the mechanism of cell death could be through the cannabinoid receptors. The results of our experiments have shown a detrimental effect of the acetaminophen metabolite p‐aminophenol onin vitrodeveloping cortical neuron viability which could act through CB1 receptors of the endocannabinoid system. These results could be especially important in recommending an analgesic for children or individuals with traumatic brain injury who have developing cortical neurons.
A Generalized Velocity Field for Plane Strain Extrusion Through Arbitrarily Curved Dies
Authors: Haghighat H. , Amjadian P.
Published: July 2011

In this paper, plane strain extrusion through arbitrarily curved dies is investigated analytically, numerically, and experimentally. Two kinematically admissible velocity fields based on assuming proportional angles, angular velocity field, and proportional distances from the midline in the deformation zone, sine velocity field, are developed for use in upper bound models. The relative average extrusion pressures for the two velocity fields are compared to each other and also with the velocity field of a reference for extrusion through a curved die. The results demonstrate that the angular velocity field is the best. Then, by using the developed analytical model, optimum die lengths which minimize the extrusion loads are determined for a streamlined die and also for a wedge shaped die. The corresponding results for those two die shapes are also determined by using the finite element code and by doing some experiments and are compared with upper bound results. These comparisons show a good agreement.
Failure of the Ingard–Myers boundary condition for a lined duct: An experimental investigation
Authors: Renou Ygaäl , Aurégan Yves
Published: July 2011

This paper deals with experimental investigation of the lined wall boundary condition in flow duct applications such as aircraft engine systems or automobile mufflers. A first experiment, based on a microphone array located in the liner test section, is carried out in order to extract the axial wavenumbers with the help of an “high-accurate” singular value decomposition Prony-like algorithm. The experimental axial wavenumbers are then used to provide the lined wall impedance for both downstream and upstream acoustic propagation by means of a straightforward impedance education method involving the classical Ingard–Myers boundary condition. The results show that the Ingard–Myers boundary condition fails to predict with accuracy the acoustic behavior in a lined duct with flow. An effective lined wall impedance, valid whatever the direction of acoustic propagation, can be suitably found from experimental axial wavenumbers and a modified version of the Ingard–Myers condition with the form inspired from a previous theoretical study [Aurégan et al., J. Acoust. Soc. Am. 109, 59–64 (2001)]. In a second experiment, the scattering matrix of the liner test section is measured and is then compared to the predicted scattering matrix using the multimodal approach and the lined wall impedances previously deduced. A large discrepancy is observed between the measured and the predicted scattering coefficients that confirms the poor accuracy provided from the Ingard–Myers boundary condition widely used in lined duct applications.
Classification of behavior using vocalizations of Pacific white-sided dolphins (Lagenorhynchus obliquidens)
Authors: Henderson E. Elizabeth , Hildebrand John A. , Smith Michael H.
Published: July 2011

Surface behavior and concurrent underwater vocalizations were recorded for Pacific white-sided dolphins in the Southern California Bight (SCB) over multiple field seasons spanning 3 years. Clicks, click trains, and pulsed calls were counted and classified based on acoustic measurements, leading to the identification of 19 key call features used for analysis. Kruskal-Wallis tests indicated that call features differ significantly across behavioral categories. Previous work had discovered two distinctive click Types (A and B), which may correspond to known subpopulations of Pacific white-side dolphins in the Southern California Bight; this study revealed that animals producing these different click types also differ in both their behavior and vocalization patterns. Click Type A groups were predominantly observed slow traveling and milling, with little daytime foraging, while click Type B groups were observed traveling and foraging. These behavioral differences may be characteristic of niche partitioning by overlapping populations; coupled with differences in vocalization patterns, they may signify that these subpopulations are cryptic species. Finally, random forest decision trees were used to classify behavior based on vocalization data, with rates of correct classification up to 86%, demonstrating the potential for the use of vocalization patterns to predict behavior.
Context-specific acoustic differences between Peruvian and Iberian Spanish vowels
Authors: Chládková Kateřina , Escudero Paola , Boersma Paul
Published: July 2011

This paper examines four acoustic properties (duration F0, F1, and F2) of the monophthongal vowels of Iberian Spanish (IS) from Madrid and Peruvian Spanish (PS) from Lima in various consonantal contexts (/s/, /f/, /t/, /p/, and /k/) and in various phrasal contexts (in isolated words and sentence-internally). Acoustic measurements on 39 speakers, balanced by dialect and gender, can be generalized to the following differences between the two dialects. The vowel /a/ has a lower first formant in PS than in IS by 6.3%. The vowels /e/ and /o/ have more peripheral second-formant (F2) values in PS than in IS by about 4%. The consonant /s/ causes more centralization of the F2 of neighboring vowels in IS than in PS. No dialectal differences are found for the effect of phrasal context. Next to the between-dialect differences in the vowels, the present study finds that /s/ has a higher spectral center of gravity in PS than in IS by about 10%, that PS speakers speak slower than IS speakers by about 9%, and that Spanish-speaking women speak slower than Spanish-speaking men by about 5% (irrespective of dialect).
Acoustic temporal modulation detection and speech perception in cochlear implant listeners
Authors: Won Jong Ho , Drennan Ward R. , Nie Kaibao , Jameyson Elyse M. , Rubinstein Jay T.
Published: July 2011

The goals of the present study were to measure acoustic temporal modulation transfer functions (TMTFs) in cochlear implant listeners and examine the relationship between modulation detection and speech recognition abilities. The effects of automatic gain control, presentation level and number of channels on modulation detection thresholds (MDTs) were examined using the listeners’ clinical sound processor. The general form of the TMTF was low-pass, consistent with previous studies. The operation of automatic gain control had no effect on MDTs when the stimuli were presented at 65 dBA. MDTs were not dependent on the presentation levels (ranging from 50 to 75 dBA) nor on the number of channels. Significant correlations were found between MDTs and speech recognition scores. The rates of decay of the TMTFs were predictive of speech recognition abilities. Spectral-ripple discrimination was evaluated to examine the relationship between temporal and spectral envelope sensitivities. No correlations were found between the two measures, and 56% of the variance in speech recognition was predicted jointly by the two tasks. The present study suggests that temporal modulation detection measured with the sound processor can serve as a useful measure of the ability of clinical sound processing strategies to deliver clinically pertinent temporal information.
The mutual roles of temporal glimpsing and vocal characteristics in cocktail-party listening
Authors: Vestergaard Martin D. , Fyson Nicholas R. C. , Patterson Roy D.
Published: July 2011

At a cocktail party, listeners must attend selectively to a target speaker and segregate their speech from distracting speech sounds uttered by other speakers. To solve this task, listeners can draw on a variety of vocal, spatial, and temporal cues. Recently, Vestergaard et al. [J. Acoust. Soc. Am. 125, 1114−1124 (2009)] developed a concurrent-syllable task to control temporal glimpsing within segments of concurrent speech, and this allowed them to measure the interaction of glottal pulse rate and vocal tract length and reveal how the auditory system integrates information from independent acoustic modalities to enhance recognition. The current paper shows how the interaction of these acoustic cues evolves as the temporal overlap of syllables is varied. Temporal glimpses as short as 25 ms are observed to improve syllable recognition substantially when the target and distracter have similar vocal characteristics, but not when they are dissimilar. The effect of temporal glimpsing on recognition performance is strongly affected by the form of the syllable (consonant-vowel versus vowel-consonant), but it is independent of other phonetic features such as place and manner of articulation.
Effect of source spectrum on sound localization in an everyday reverberant room
Authors: Ihlefeld Antje , Shinn-Cunningham Barbara G.
Published: July 2011

Two experiments explored how frequency content impacts sound localization for sounds containing reverberant energy. Virtual sound sources from thirteen lateral angles and four distances were simulated in the frontal horizontal plane using binaural room impulse responses measured in an everyday office. Experiment 1 compared localization judgments for one-octave-wide noise centered at either 750 Hz (low) or 6000 Hz (high). For both band-limited noises, perceived lateral angle varied monotonically with source angle. For frontal sources, perceived locations were similar for low- and high-frequency noise; however, for lateral sources, localization was less accurate for low-frequency noise than for high-frequency noise. With increasing source distance, judgments of both noises became more biased toward the median plane, an effect that was greater for low-frequency noise than for high-frequency noise. In Experiment 2, simultaneous presentation of low- and high-frequency noises yielded performance that was less accurate than that for high-frequency noise, but equal to or better than for low-frequency noise. Results suggest that listeners perceptually weight low-frequency information heavily, even in reverberant conditions where high-frequency stimuli are localized more accurately. These findings show that listeners do not always optimally adjust how localization cues are integrated over frequency in reverberant settings.
Total annoyance from an industrial noise source with a main spectral component combined with a background noise
Authors: Alayrac M. , Marquis-Favre C. , Viollon S.
Published: July 2011

When living close to an industrial plant, people are exposed to a combination of industrial noise sources and a background noise composed of all the other noise sources in the environment. As a first step, noise annoyance indicators in laboratory conditions are proposed for a single exposure to an industrial noise source. The second step detailed in this paper involves determining total annoyance indicators in laboratory conditions for ambient noises composed of an industrial noise source and a background noise. Two types of steady and permanent industrial noise sources are studied: low frequency noises with a main spectral component at 100 Hz, and noises with a main spectral component in middle frequencies. Five background noises are assessed so as to take into account different sound environments which can usually be heard by people living around an industrial plant. One main conclusion of this study is that two different analyses are necessary to determine total annoyance indicators for this type of ambient noise, depending on the industrial noise source composing it. Therefore, two total annoyance indicators adapted to the ambient noises studied are proposed.
Evaluation of speech transmission in open public spaces affected by combined noises
Authors: Lee Pyoung Jik , Jeon Jin Yong
Published: July 2011

In the present study, the effects of interference from combined noises on speech transmission were investigated in a simulated open public space. Sound fields for dominant noises were predicted using a typical urban square model surrounded by buildings. Then road traffic noise and two types of construction noises, corresponding to stationary and impulsive noises, were selected as background noises. Listening tests were performed on a group of adults, and the quality of speech transmission was evaluated using listening difficulty as well as intelligibility scores. During the listening tests, two factors that affect speech transmission performance were considered: (1) temporal characteristics of construction noise (stationary or impulsive) and (2) the levels of the construction and road traffic noises. The results indicated that word intelligibility scores and listening difficulty ratings were affected by the temporal characteristics of construction noise due to fluctuations in the background noise level. It was also observed that listening difficulty is unable to describe the speech transmission in noisy open public spaces showing larger variation than did word intelligibility scores.
Acoustic emission localization in complex dissipative anisotropic structures using a one-channel reciprocal time reversal method
Authors: Ciampa Francesco , Meo Michele
Published: July 2011

This paper presents an imaging method for the localization of the impact point in complex anisotropic structures with diffuse field conditions, using only one passive transducer. The proposed technique is based on the reciprocal time reversal approach (inverse filtering) applied to a number of waveforms stored into a database containing the experimental Green’s function of the structure. Unlike most acoustic emission monitoring systems, the present method exploits the benefits of multiple scattering, mode conversion, and boundaries reflections to achieve the focusing of the source with high resolution. Compared to a standard time reversal approach, the optimal refocusing of the back propagated wave field at the impact point is accomplished through a “virtual” imaging process. The robustness of the inverse filtering technique is experimentally demonstrated on a dissipative stiffened composite panel and the source position can be retrieved with a high level of accuracy in any position of the structure. Its very simple configuration and minimal processing requirements make this method a valid alternative to the conventional imaging Structural Health Monitoring systems for the acoustic emission source localization.
Molecular dynamics in weakly polar nematic liquid crystal doped with dye
Authors: Yadav Satya Prakash , Pandey Kamal Kumar , Misra Abhishek Kumar , Dixit Sudhaker , Manohar Rajiv
Published: July 2011

Our intention in the present work is to find out the role of dye in the molecular orientation of the weakly polar nematic liquid crystal D6AOB. The doping of a dye introduces a disturbance in the molecular arrangement of the nematic liquid crystal molecules. However, this disturbance is found to be sensitive to the concentration of the dye dispersed in the nematic liquid crystal. It is found that orientation in the dyed nematic liquid crystal is less ordered than the orientation in the pure nematic liquid crystals. This behavior has been explained on the basis of intermolecular interaction, i.e., dipole–dipole interaction.
Factorial correlators and oscillatory multiplicity moments of ring-like and jet-like events in 16O–Ag/Br interactions at 60 A GeV1Supported by Department of Science and Technology, Government of India through SERC Fast Track Scheme for Young Scientists Project.
Authors: Haldar Prabir Kumar , Manna Sanjib Kumar
Published: July 2011

The analysis of ring-like and jet-like events in 16O–Ag/Br interactions at 60 A GeV is performed using the methods of factorial correlators and oscillatory multiplicity moments. The investigation reveals that the correlators increase with a decrease of the size of bin separation interval, following the power law, and suggest the presence of the intermittent nature of the dynamical fluctuations measured. The analysis shows the signal of the intermittency to be stronger in the ring-like events. However, both the ring-like and jet-like events are found to be consistent with the α-model predictions. The oscillatory moments are found to follow a different behavior in ring-like events and jet-like events. In most cases, the simulation fails to reproduce the measurements.
Cross sections for electron-impact ionization of water molecules
Authors: Sahlaoui Mohammed , Bouamoud Mammar
Published: July 2011

Theoretical triple differential cross sections for the electron-impact ionization of water molecules at high incident energy are presented. The results are derived using an analytical expression for the transition amplitude in the framework of the one Coulomb wave model. For accurate comparison with experiments, an average of the cross sections on the random orientations of the target has been used. The comparison of our results with the available experimental measurements shows that our formalism is able to describe the water molecule ionization process with good precision. The present approach can be used to describe the ionization of other molecular targets with chemical form XHn by other charged particles.
Temperature-Programmed Desorption Observation of Graphene-on-Silicon Process
Authors: Abe Shunsuke , Handa Hiroyuki , Takahashi Ryota , Imaizumi Kei , Fukidome Hirokazu , Suemitsu Maki
Published: July 2011

With its industrial adaptability, graphene-on-silicon (GOS), formed by ultrahigh-vacuum annealing of a SiC thin film on a silicon substrate, is attracting recent attention. Little is known, however, about the growth mechanism of GOS. We demonstrate in this paper that temperature-programmed-desorption spectroscopy of deuterium (D2-TPD) can be a powerful in-situ probe to investigate the surface chemistry during formation of epitaxial graphene (EG) on SiC crystals. Using the D2-TPD, the surface stoichiometry and the back-bonds of the surface atoms, including their dependence on the crystallographic orientations [Si(111), Si(100), and Si(110)] can be obtained. Difference in the growth mechanism of GOS among the orientations is discussed based on the results.
Polymer Material as a Gate Dielectric for Graphene Field-Effect-Transistor Applications
Authors: Jung Myung-Ho , Handa Hiroyuki , Takahashi Ryota , Fukidome Hirokazu , Suemitsu Tetsuya , Otsuji Taiichi , Suemitsu Maki
Published: July 2011

Epitaxial-graphene field-effect transistor (EG-FET) with a polymer gate dielectric was fabricated and their electrical characteristics were investigated. The epitaxial graphene layer was formed on a semi-insulating 6H-SiC substrate by a high-temperature annealing in ultrahigh vacuum. The formation of graphene was confirmed by low-energy electron diffraction (LEED), Raman-scattering spectroscopy and X-ray photoelectron spectroscopy (XPS). The polymer gate dielectric (ZEP520a) layer was formed by spin coating, which exhibits good dielectric properties without noticeable structural degradation of the graphene layer. The EG-FETs with this polymer gate dielectric shows an n-type characteristic, with the field-effect mobility of 580 cm2 V-1 s-1.
Investigation of Graphene Field Effect Transistors with Al2O3 Gate Dielectrics Formed by Metal Oxidation
Authors: Jung Myung-Ho , Handa Hiroyuki , Takahashi Ryota , Fukidome Hirokazu , Suemitsu Tetsuya , Otsuji Taiichi , Suemitsu Maki
Published: July 2011

We propose the epitaxial graphene field-effect transistors (EG-FETs) with Al2O3 gate dielectric formed by metal oxidation on semi-insulating 6H-SiC substrate. The Al2O3 gate dielectric layer was formed by thermally oxidizing a thin Al film at 500 °C in an O2 ambient. The electrical characteristics of EG-FETs with Al2O3 gate dielectric have been investigated, which exhibits p-type behavior with the field effect mobility of 120 cm2 V-1 s-1. After the Al2O3 formation, the FWHM of G' and D peaks in the Raman-scattering spectra increased, indicating degradation of graphene and thereby accounting for the low field effect mobility of the EG-FETs. This finding suggests that the optimization of post growth heat treatments, such as oxidation and metallization, should play a decisive role in tuning the quality of graphene and the performance of the device made thereof.
Label-Free Aptamer-Based Immunoglobulin Sensors Using Graphene Field-Effect Transistors
Authors: Ohno Yasuhide , Maehashi Kenzo , Inoue Koichi , Matsumoto Kazuhiko
Published: July 2011

Electrical detection of specific proteins was demonstrated using aptamer-modified graphene field-effect transistors (G-FETs). Immunoglobulin E (IgE) aptamers were immobilized onto the graphene surface with 1-pyrenebutanoic acid succinimidyl ester as a linker. From an atomic-force microscopy image, the height of the graphene channel was determined to be approximately 3 nm, indicating the successful functionalization of aptamers. The slope of the transport characteristics before and after aptamer functionalization did not change, indicating that the functionalization process was carried out without introducing defects. The aptamer-modified G-FET successfully detected only the target protein while the drain current of the bare G-FETs changed by various proteins. These results suggest that the binding of the non-target protein to the graphene channel surface was sufficiently suppressed.
Dielectric Properties and Oxide-Ion Conduction for Y2O3 Stabilized ZrO2 and Bi2O3
Authors: Yagi Yuhji , Saito Miwa , Yamamura Hiroshi
Published: July 2011

The oxide-ion conduction and dielectric properties of 8 mol % Y2O3 stabilized ZrO2 (8YSZ) and 25 mol % Y2O3 stabilized Bi2O3 (25YSB) which are oxide ion conductors having a fluorite type structure were investigated. The numerical analyses for the frequency dependences of dielectric constants (εr') and dielectric loss factors (εr'') revealed that the dielectric properties were explained by Debye-type polarization due to dopant–vacancy associates and/or polarization due to charging or loss current. No Debye-type polarization was observed in 25YSB because of no effective charge at the Y3+-doped Bi3+ site. On the other hand, three Debye-type dipoles observed in 8YSZ were assigned to the polarization of oxide-ion conduction, and two kinds of associates, [YZr'–Vo
••]• and [YZr'–Vo
••–YZr']×, due to the interaction between doped cation (YZr') and oxygen vacancy (Vo
••). The frequency dependence of dielectric loss tangent (tan
δ) in 25YSB was ascribed to the interface loss due to the charged current, while that of tan
δ in 8YSZ was ascribed to the Debye-type dipoles in addition to the interface loss.
Ambient Dependence of Photoluminescence for ZnO Nanocrystalline Films Synthesized in a Sonochemical Method
Authors: Lee Dong Jae , Park Jong Hyurk , Yee Kee Joo , Lee Yun Sang
Published: July 2011

We investigated the photoluminescence (PL) spectra of solution-based synthesized ZnO nanocrystalline (NC) films under various ambient conditions. While the PL spectra typically showed a sharp peak near 375 nm (near-band-edge, NBE) and a broad structure near 550 nm (deep level, DL), the NBE peak was enhanced and the DL emission was significantly suppressed in an O2-free atmosphere at room temperature. Interestingly, the PL spectra changed in an opposite manner in an O2-rich atmosphere. These findings indicate that the light emission from ZnO NC films is easily controlled by the O2 concentration in the atmosphere at room temperature, which is clearly distinguished from the post-annealing effect.
Optical Parametric Amplifier Pumped at 266 nm toward Ultrashort Near-Ultraviolet Gigawatt Pulses
Authors: Tanigawa Takashi , Yamane Keisaku , Karasawa Naoki , Yamashita Mikio
Published: July 2011

Near-ultraviolet (UV) broadband (370–470 nm) amplification up to 2.4 µJ energy from a single-pass β-barium borate (BBO) crystal is demonstrated by noncollinear optical parametric amplification (NOPA) pumped by the third harmonic (TH, 40 µJ pump energy) of Ti:sapphire laser pulses at 1 kHz repetition rate. The result of simulation with the pump depletion effect due to two-photon absorption (TPA) shows an excellent agreement with the experimental demonstration. Further simulation suggests that the intense pump (energy of 1 mJ) is useful, in spite of the increase in TPA, for obtaining high-energy amplification of 47 µJ for several femtosecond near-UV pulses with 4.7% efficiency using a commercially available high-power femtosecond laser system.
Analytical Model for Subthreshold Swing and Threshold Voltage of Surrounding Gate Metal–Oxide–Semiconductor Field-Effect Transistors
Authors: Mei Guanghui , Hu Guangxi , Hu Shuyan , Gu Jinglun , Liu Ran , Tang Tingao
Published: July 2011

We investigate analytically the metal–oxide–semiconductor field-effect transistor (MOSFET) with a surrounding gate (SG). We develop and present an analytical model for subthreshold swing and threshold voltage. Poisson's equation is solved analytically. The analytical expressions for electrical potential, drain current in the subthreshold region, subthreshold swing, and threshold voltage are obtained. The analytical results are compared with simulated results, and the two agree very well. The subthreshold swing of an SG MOSFET can be improved either by reducing the silicon body radius or by reducing the oxide thickness. The threshold voltage decreases with reductions in the channel length, the silicon body radius, or the oxide thickness. Based on the threshold voltage model, drain induced barrier lowering (DIBL) effect is explored, and we find that DIBL effect is more severe for a device with a larger silicon body radius, and/or with a shorter channel length.
Study on the Electrical and Thermal Conductivity of Ordered Mesoporous TiO2 Thin Film Incorporated with Pt Nanoparticles
Authors: Ha Tae-Jung , Choi Yong-June , Jung Sin-Young , Seo Won-Seon , Lim Young Soo , Shin Sangwoo , Cho Hyung Hee , Park Hyung-Ho
Published: July 2011

Ordered mesoporous TiO2 films with incorporated Pt nanoparticles were prepared using titanium tetraisopropoxide, hexachloroplatinic acid hexahydrate, and Pluronic P-123 as a titania precursor, a Pt precursor, and a structure-directing agent, respectively. Pt nanoparticles were introduced to enhance the electrical properties of the mesoporous films, which have excellent thermal insulation properties. We confirmed that the synthesized composite films with Pt nanoparticles had an ordered pore structure with anatase phase TiO2 by both small-angle and wide-angle X-ray diffraction analyses. Although the porosity of the composite film decreased from 37.6 to 29.3% when Pt nanoparticles were included, the conductivity ratio (σ/κ) of the film increased greatly, up to approximately 1370 K V-2, due to the greater increase in electrical conductivity than thermal conductivity. Based on our results, we conclude that by incorporating Pt nanoparticles into ordered mesoporous TiO2 film, the thermoelectric properties of the mesoporous films can be improved.
Stress Wave Propagation in Ni–Mn–Ga Ferromagnetic Shape Memory Alloys
Authors: Pandi Rajasabai Senthur , Chokkalingam Ramalingam , Mahendran Manickam
Published: July 2011

Ni–Mn–Ga ferromagnetic shape memory alloys (FSMAs) are a prominent candidate for actuation application due to their large magnetic field induced strain (MFIS). MFIS in these alloys are mainly due to the twin variant reorientation. This can be achieved only above the magnetic threshold, which requires a large electromagnet. The higher threshold magnetic field for magnetic actuation can be reduced by the assistance of stress waves. The present work is focused on the stress wave propagation in Ni–Mn–Ga alloys. It has been observed that the stress amplitude is high in the frequency range 2 to 5 kHz and is found to be dependent on the input voltage supplied to the actuator which gives out stress wave. The advantage is that, in this frequency range, the threshold field for magnetic actuation can be reduced. It is noted that the stress amplitude is higher in the Ni–Mn–Ga polycrystal (456 mV) than the Ni–Mn–Ga single crystal (385 mV) for the 30 V input peak to peak voltage (Vpp). The finding of this work supports the Ni–Mn–Ga alloy polycrystals for actuation applications with the assistance of stress waves.
Thermal-Annealing Effects on Dopant Redistribution in Nanoscale Si Fin
Authors: Izumida Takashi , Okano Kimitoshi , Kanemura Takahisa , Kondo Masaki , Inaba Satoshi , Itoh Sanae , Aoki Nobutoshi , Toyoshima Yoshiaki
Published: July 2011

We investigated the diffusion of implanted boron and phosphorous in a narrow Si fin during rapid thermal annealing (RTA) at 1000 °C for 10 s. We found that the boron diffusion is described by the conventional diffusion model. We also found that the point defects (interstitial Si and vacancy) play an important role in determining the detailed distribution of boron in a narrow Si fin. On the other hand, the phosphorous diffusion shows anomalous behavior in the peak region of the Si fin, namely large dose loss from the Si region. We found experimentally that about 50% of implanted phosphorous atoms in the Si fin diffused out from the Si region by the annealing (1000 °C, 10 s). The simulation result shows that the experimental result of phosphorous diffusion is reproduced by taking into account the dose loss model through introduction of the interfacial trap layer. Because the phosphorous distribution is largely modified by the dose loss effect, it is considered that the large dose loss of phosphorous gives rise to large impacts on the device characteristics of fin field effect transistors (FinFETs).
Fabrication of Two-Depth Apodized Grating by Selective Etching of InP in CH4/H2 Reactive Ion Etching
Authors: Yamamoto Norio , Nunoya Nobuhiro
Published: July 2011

We fabricated the basic structure of an apodized grating with two depths of 120 and 200 nm for InP in one etching process during reactive ion etching (RIE) with methane and hydrogen. In the process, we first performed selective RIE, in which InP windows of the grating were etched in a region with a thick layer but not etched with polymer deposition in a region without the thick layer. Next, we performed oxygen plasma exposure to remove the polymer and a second RIE for the windows of the gratings both with and without the thick layers.
Numerical Analysis for Acoustic Resonance of One-Dimensional Nonlinear Elastic Bar
Authors: Tarumi Ryuichi , Matsuhisa Tomohiro , Shibutani Yoji
Published: July 2011

The free vibration acoustic resonance of a one-dimensional nonlinear elastic bar has been studied within a framework of the calculus of variation. The one-dimensional deformation function is expanded by a complex Fourier series, and the coefficients as well as the resonance frequency are determined from a direct analysis based on the Ritz method. This numerical analysis revealed that the elastic bar shows prominent nonlinear features such as the amplitude dependence of resonance frequency and the small oscillation of pseudo-nodal points. From a spectral analysis for the first resonant vibration mode, we confirmed nonlinear excitations of high-frequency and/or high-wave-number vibration modes. The mechanism of the mode selection is discussed.
Application of Complex Series Dynamics to Electromechanical Coupling System
Authors: Ohki Michio
Published: July 2011

The characteristics of an electromechanical transducer are expressed in a distributed-parameter basis without using any lumped-parameter components. Two energy modes, elastic mode and dielectric mode, are considered, which interact with each other in some mathematical regularities. Physical processes on the two modes are represented with some matrix operation, and the infinite geometric series of the matrices, reflecting the boundary conditions of transducer, provides frequency characteristics from the viewpoint of locally stored energy in the transducer. The sum of the local characteristics provides the global characteristics of the transducer. The energy transfer and the shift of resonance frequency owing to the electromechanical coupling can be calculated by this method.
Development of Reflection Objective-Employed Collinear Mode-mismatched Thermal Lens Microscope
Authors: Fujii Noriyuki , Harata Akira
Published: July 2011

A reflection objective-employed collinear thermal lens microscope (roco-TLM) is developed in which a reflection objective lens is used for collinearly focusing, in a mode-mismatched configuration, both an excitation laser beam at 260 nm and a probe laser beam at 632 nm. With the microscope, unsymmetrical distortions of a thermal lens image obtained with a reflection objective were reduced. The cause of the diffraction pattern in a thermal lens image observed with the roco-TLM is discussed as well.
Harmonic Imaging of Plastic Deformation in Thin Metal Plates Using Nonlinear Ultrasonic Method
Authors: Kawashima Koichiro
Published: July 2011

Plastic deformation in perforated SUS 304 steel strips is imaged by an immersion resonant higher harmonic technique. The higher harmonic components are extracted from resonant waveforms received through a high-pass filter. Plastic zones are imaged by higher harmonic amplitude and delay time from the start of resonance to the peak amplitude. The higher harmonic amplitude corresponds well to the extent of plastic deformation; namely, it is highest in highly deformed regions and lowest in un-deformed regions. This technique could be applied to evaluate material degradation before crack initiation.
Buried Object Detection Method Using Optimum Frequency Range in Extremely Shallow Underground
Authors: Sugimoto Tsuneyoshi , Abe Touma
Published: July 2011

We propose a new detection method for buried objects using the optimum frequency response range of the corresponding vibration velocity. Flat speakers and a scanning laser Doppler vibrometer (SLDV) are used for noncontact acoustic imaging in the extremely shallow underground. The exploration depth depends on the sound pressure, but it is usually less than 10 cm. Styrofoam, wood (silver fir), and acrylic boards of the same size, different size styrofoam boards, a hollow toy duck, a hollow plastic container, a plastic container filled with sand, a hollow steel can and an unglazed pot are used as buried objects which are buried in sand to about 2 cm depth. The imaging procedure of buried objects using the optimum frequency range is given below. First, the standardized difference from the average vibration velocity is calculated for all scan points. Next, using this result, underground images are made using a constant frequency width to search for the frequency response range of the buried object. After choosing an approximate frequency response range, the difference between the average vibration velocity for all points and that for several points that showed a clear response is calculated for the final confirmation of the optimum frequency range. Using this optimum frequency range, we can obtain the clearest image of the buried object. From the experimental results, we confirmed the effectiveness of our proposed method. In particular, a clear image of the buried object was obtained when the SLDV image was unclear.
Magnetic Sensor Based on Surface Acoustic Wave Resonators
Authors: Kadota Michio , Ito Shigeo , Ito Yoshihiro , Hada Takuo , Okaguchi Kenjiro
Published: July 2011

In this paper, we describe a new type of magnetic surface acoustic wave (SAW) sensor that consists of interdigital transducers made of a magnetostrictive material, Ni, on a quartz substrate. This sensor can be used as an element of a resonator-type wireless SAW sensor system because it has a high Q. Moreover, it has the merits of being fabricated easily using the existing process for SAW devices because its structure is the same as that of general SAW resonators. When an external magnetic field of about 100 mT was applied perpendicularly to the direction of SAW propagation, the frequency change obtained was 200 ppm. In addition, the developed sensor was applied in a passive and wireless open/close sensing system and the reading distance obtained was 3 m.